Antibiotics

26 pages, 2475 KB

Open AccessEditor’s ChoiceReview

Current Advances in Developing New Antimicrobial Agents Against Non-Tuberculous Mycobacterium

by Jane Cross, Nupur Gargate and Khondaker Miraz Rahman

Antibiotics 2025, 14(12), 1189; https://doi.org/10.3390/antibiotics14121189 - 21 Nov 2025

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Non-tuberculous mycobacteria (NTM) comprise more than 190 species capable of causing severe pulmonary, lymphatic, cutaneous, and disseminated infections, particularly in immunocompromised populations. Over the past two decades, the global incidence of NTM infections has risen steadily, underscoring an urgent unmet medical need. Treatment [...] Read more.

Non-tuberculous mycobacteria (NTM) comprise more than 190 species capable of causing severe pulmonary, lymphatic, cutaneous, and disseminated infections, particularly in immunocompromised populations. Over the past two decades, the global incidence of NTM infections has risen steadily, underscoring an urgent unmet medical need. Treatment remains highly challenging due to intrinsic antimicrobial resistance and the requirement for prolonged multidrug regimens that are often poorly tolerated and associated with unsatisfactory outcomes. At the same time, the development of novel therapies has lagged behind other disease areas, hindered by the high costs of antimicrobial drug discovery and the relatively low commercial return compared with treatments for chronic conditions. Over the past decade, discovery and development have diversified across novel small molecules, next-generation analogues of existing classes, and adjunctive or host-directed strategies. While most candidates remain preclinical, several agents have advanced clinically in other infections, including gepotidacin (topoisomerase inhibitor; FDA-approved 2025 for urinary tract infection (UTI)), sulbactam–durlobactam (DBO β-lactamase inhibitor; FDA-approved 2023 for Acinetobacter baumannii complex), and contezolid, supporting repurposing opportunities for NTM. Conversely, SPR720 (gyrase B prodrug) was suspended after not meeting its Phase 2 endpoint in 2024, underscoring translational risk. Overall, the NTM pipeline is expanding, with near-term progress most likely from repurposed agents and optimised combinations, alongside earlier-stage candidates that target biofilms or resistance mechanisms. This review aims to provide a critical and up-to-date overview of emerging antimicrobial strategies against NTM, highlighting recent advances, translational challenges, and opportunities to accelerate the development of effective therapeutics. Full article

(This article belongs to the Special Issue Design, Synthesis and Biological Evaluation of Antibacterial Compounds)

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12 pages, 537 KB

Open AccessEditor’s ChoiceArticle

Clinical Characteristics and Treatment Strategies in a Cohort of Patients with Tularemia: A Retrospective Multicenter Analysis of 65 Cases in Germany

by Benjamin Arnold, Henning Trawinski, Nils Kellner, Hans-Martin Orth, Daniela Tominski, Agata Mikolajewska, Katja Rothfuss, Gesa Grupe, Dominik Ruf, Friedrich Reichert, Daniela Jacob, Klaus Heuner, Kathrin Marx and Christoph Lübbert

Antibiotics 2025, 14(11), 1169; https://doi.org/10.3390/antibiotics14111169 - 20 Nov 2025

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Abstract

Background: In recent years, there has been a significant increase in cases of tularemia, a rare zoonotic disease caused by Francisella tularensis, in Europe. Methods: To investigate the epidemiological, clinical, and therapeutic characteristics of tularemia patients in Germany, we performed a retrospective [...] Read more.

Background: In recent years, there has been a significant increase in cases of tularemia, a rare zoonotic disease caused by Francisella tularensis, in Europe. Methods: To investigate the epidemiological, clinical, and therapeutic characteristics of tularemia patients in Germany, we performed a retrospective evaluation of tularemia cases treated between 2010 and 2025 at selected treatment centers of the Permanent Working Group of Competence and Treatment Centers for High Consequence Infectious Diseases (STAKOB) at the Robert Koch Institute. Results: A total of 65 patients (median age: 48.5 years; 66.2% male) were identified. Most common manifestation was ulceroglandular (70.7%), followed by oropharyngeal (13.8%), pulmonary (10.8%), oculoglandular (7.7%), typhoidal (4.6%), and meningitic (4.6%). Serological confirmation of the diagnosis was achieved in all patients (90.8% ELISA, 46.2% Western blot). PCR-based direct pathogen detection was successful in 26.2%. Bloodstream infection was detected in 4.6%. Median incubation period was 7 days (IQR: 4–10), with fever being the most common symptom in 96.9% and lymphadenopathy in 46.2%. Median time to recovery was 56 days (IQR: 37–80) in patients diagnosed and treated early (≤3 weeks after symptom onset), compared to 84 days (IQR: 66–182) in patients with late diagnosis (>3 weeks after symptom onset; p = 0.015). Empirical therapy with beta-lactam antibiotics was initiated in 49.2% of cases. Following suspicion of tularemia, 96.9% received recommended treatment with fluoroquinolones, tetracyclines, or aminoglycosides. Conclusions: Delayed diagnosis and inappropriate initial therapy can significantly prolong disease courses and increase morbidity. Early treatment with effective antibiotics, considering the intrinsic beta-lactam resistance of Francisella tularensis, leads to faster recovery. Full article

(This article belongs to the Section Antibiotic Therapy in Infectious Diseases)

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17 pages, 3008 KB

Open AccessEditor’s ChoiceArticle

Synthesis and Structure–Activity Relationship Study of 2-(amino)quinazolin-4(3H)-one Derivatives as Potential Inhibitors of Methicillin-Resistant Staphylococcus aureus (MRSA)

by Jun Young Lee, Hyunjung Lee, Sungmin Kim, Jihwan Gim, Yunmi Lee, Chae Jo Lim, Hyun-Seob Song, Hyeung-geun Park, Soojin Jang and Chul Min Park

Antibiotics 2025, 14(10), 967; https://doi.org/10.3390/antibiotics14100967 - 25 Sep 2025

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Abstract

Background/Objectives: The rise in methicillin-resistant Staphylococcus aureus (MRSA) demands new therapeutic strategies. In this study, a series of 2-(amino)quinazolin-4(3H)-one derivatives were synthesized and evaluated for antistaphylococcal activity. Methods/Results: Through screening against S. aureus ATCC25923 and USA300 JE2, several submicromolar inhibitors were [...] Read more.

Background/Objectives: The rise in methicillin-resistant Staphylococcus aureus (MRSA) demands new therapeutic strategies. In this study, a series of 2-(amino)quinazolin-4(3H)-one derivatives were synthesized and evaluated for antistaphylococcal activity. Methods/Results: Through screening against S. aureus ATCC25923 and USA300 JE2, several submicromolar inhibitors were identified. Among them, compound 6l, which contains a 7-chloro substituent on the key parental scaffold, exhibited strong overall antibacterial activity (MIC₅₀: 1.0 µM, ATCC25923; 0.6 µM, JE2) and served as a lead for further structural optimization. Structure–activity relationship analysis showed that substitution at the 2-position was critical, with its optimized analog 6y (3,4-difluorobenzylamine) exhibiting the highest potency (MIC₅₀: 0.36 µM, ATCC25923; 0.02 µM, JE2). Cytotoxicity assays in HepG2 cells revealed six compounds with IC₅₀ values above 20 µM, yielding efficacy windows greater than 10. Compound 6y exhibited an exceptional index (~885). Consistently, in an H460 lung epithelial infection model mimicking MRSA pneumonia, 6y significantly reduced intracellular bacterial loads with minimal host cell damage, outperforming comparator compounds. Conclusions: These findings highlight 2-(amino)quinazolin-4(3H)-one derivatives, particularly 6y, as promising leads for the development of new antistaphylococcal agents. Full article

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20 pages, 4943 KB

Open AccessEditor’s ChoiceArticle

Phage Resistance Modulates Escherichia coli B Response to Metal-Based Antimicrobials

by Franklin C. Ezeanowai, Akamu J. Ewunkem, Ugonna C. Morikwe, Larisa C. Kiki, Lindsey W. McGee, Joseph L. Graves, Jr. and Liesl K. Jeffers-Francis

Antibiotics 2025, 14(9), 942; https://doi.org/10.3390/antibiotics14090942 - 18 Sep 2025

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Abstract

Background/Objective: The rise of multidrug-resistant bacteria underscores the urgent need for alternative antimicrobial strategies. Metal-based compounds and bacteriophage (phage) therapy have emerged as promising candidates, but the evolutionary trade-offs associated with these selective pressures and their combination remain poorly understood. This study [...] Read more.

Background/Objective: The rise of multidrug-resistant bacteria underscores the urgent need for alternative antimicrobial strategies. Metal-based compounds and bacteriophage (phage) therapy have emerged as promising candidates, but the evolutionary trade-offs associated with these selective pressures and their combination remain poorly understood. This study aimed to investigate how prior exposure to T4 phage influences Escherichia coli B’s subsequent adaptation to iron (III) stress and to assess the resulting phenotypic and genomic signatures of dual resistance. Method: In this study, we performed experimental evolution using Escherichia coli B to investigate adaptive responses under four conditions: control (LB broth), T4 phage-only, iron (III) sulfate-only, and sequential phage followed by iron (III) exposure. Each treatment consisted of ten independently evolved populations (biological replicates), all derived from a common ancestral strain and passaged daily for 35 days. Phage resistance evolved rapidly, with complete resistance observed within 24 h of exposure. Results: In contrast, iron-selected populations evolved tolerance to high iron concentrations (1000–1750 mg/L) over time at a cost to resistance in other metals (gallium and iron (II) and antibiotics (tetracycline). Notably, prior phage exposure altered these outcomes: phage/iron-selected populations retained phage resistance and iron tolerance but showed diminished resistance to iron (II) and distinct antibiotic sensitivity profiles. Whole-genome sequencing revealed stressor-specific adaptations: large deletions in phage receptor-related genes (waaA and waaG) under phage pressure, and selective sweeps in iron-adapted populations affecting regulatory and membrane-associated genes (qseB, basR, aroK, fieF, rseB, and cpxP). Conclusions: These results demonstrate that the sequence of environmental stressors significantly shapes phenotypic and genetic resistance outcomes. Our findings highlight the importance of fitness epistasis and historical contingency in microbial adaptation, with implications for the design of evolution-informed combination therapies. Full article

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11 pages, 863 KB

Open AccessEditor’s ChoiceArticle

Testing Analytical Methods for Antibiotic Detection in Tenebrio molitor Larvae: A Controlled Feeding Trial

by Tomke Asendorf, Christine Wind and Andreas Vilcinskas

Antibiotics 2025, 14(9), 909; https://doi.org/10.3390/antibiotics14090909 - 9 Sep 2025

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Abstract

Background: As edible insects gain importance as sustainable protein sources, their integration into the food system requires that they meet the same safety standards as conventional animal products. This includes systematic testing for residues of pharmacologically active substances, such as antibiotics. To enable [...] Read more.

Background: As edible insects gain importance as sustainable protein sources, their integration into the food system requires that they meet the same safety standards as conventional animal products. This includes systematic testing for residues of pharmacologically active substances, such as antibiotics. To enable such monitoring, validated analytical methods for insect matrices are essential—but currently lacking. This study evaluates whether LC-MS/MS methods already validated for conventional animal products are suitable for detecting antibiotics in edible insects. Methods:Tenebrio molitor larvae were fed wheat flour containing 10 mg of tiamulin or chloramphenicol and 31.3 mg erythromycin per 100 g flour. The antibiotics were mixed into the feed, and their homogeneity and stability were confirmed. After seven days of feeding and a 24-h fasting period, larval samples were analyzed by LC-MS/MS. Results: All three antibiotics were detected in the insects. After seven days, mealworms contained 6.8 ± 0.3 mg/kg tiamulin, 1.4 ± 0.2 mg/kg chloramphenicol, and 224.5 ± 111 mg/kg erythromycin. Following the 24-hour fasting period, concentrations declined markedly to 0.6 ± 0.03 mg/kg, 0.2 ± 0.002 mg/kg, and 130.5 ± 0.7 mg/kg, respectively. Conclusions: The detection of all three antibiotics demonstrates that existing LC-MS/MS methods can be applied to insect matrices. Owing to the small number of replicates and the exploratory nature of the trial, these residue levels should be interpreted qualitatively as a proof of concept. The study provides a reproducible model for further feeding trials and underscores the need for more comprehensive validation. Potential drivers of antibiotic misuse in insect farming are discussed as a basis for developing and expanding testing methods to ensure the food safety of edible insects. Full article

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20 pages, 2009 KB

Open AccessEditor’s ChoiceArticle

Optimizing the Routine Use of Clinical Guidelines by Addition of Supplements (Probiotics and/or Bismuth) to Helicobacter pylori Eradication Protocols in a Clarithromycin Resistant and Tetracycline/Bismuth Naive Area: A Real-World Data Retrospective Analysis of 402 Cases (2016–24) in a Single Gastroenterology Unit

by András Gelley, Noémi Kéri, Péter Birinyi, Kinga Komka, Vajk Hardy, László Döngölő, Dóra Szeli and Ibolya Czegle

Antibiotics 2025, 14(9), 870; https://doi.org/10.3390/antibiotics14090870 - 29 Aug 2025

Viewed by 1841

Abstract

Background: The official current guideline for Helicobacter pylori (H. pylori) eradication is to use tetracycline–bismuth-based protocols as first line treatment due to the increasing incidence of clarithromycin resistance in the last decade. The unavailability of tetracycline and bismuth-containing medicines, however, is [...] Read more.

Background: The official current guideline for Helicobacter pylori (H. pylori) eradication is to use tetracycline–bismuth-based protocols as first line treatment due to the increasing incidence of clarithromycin resistance in the last decade. The unavailability of tetracycline and bismuth-containing medicines, however, is an issue in many countries, limiting the routine use of these protocols. The value of using additional probiotics in eradication protocols is also unclear. Direct comparison data on the effect of available bismuth compounds and different probiotic strains on eradication outcome are limited. Goal: The aim of our investigation was to find optimal eradication protocols, supplementations and treatment duration for routine clinical use in our gastroenterology unit, located in a highly clarithromycin-resistant and tetracycline–bismuth-naïve area. Materials and Methods: We conducted a retrospective real-world data analysis of 402 H. pylori positive patients between 2016 and 2024. H. pylori infection was diagnosed using histological examination of gastroscopy samples obtained from the gastric antrum. For the evaluation of treatment success or failure, ¹⁴C breath tests and stool H. pylori antigen tests were performed. Data on patient characteristics and treatment protocols were collected from our electronic patient record system, and treatment success was compared between the different treatment regimes. Results: Despite the regional clarithromycin resistance, supplementing clarithromycin-based regimens with bismuth and probiotic during the 14-day treatment duration showed a high and comparable cure rate when compared to tetracycline-based regimens, which are the current first-line therapies. When tetracycline-based combination is available, it is recommended to use it with an additional probiotic to achieve the best possible outcome. Comparison of the effect of available bismuth preparations on treatment success showed no significant difference. Generally, probiotic-containing protocols are more successful, compared to those treatments without this supplement. There was no statistical difference in the cure rates amongst the four probiotic strains used, where sample size allowed statistical analysis. Furthermore, supplementation with probiotics Lactobacillus reuteri ATCC PTA 6475 or Lactobacillus reuteri Protectis^® DSM 17938 showed promising high treatment success rates (85.2% and 100.0%, respectively) in our study. Full article

(This article belongs to the Special Issue Clinical Guidelines and Real Practice of Antimicrobial Pharmacotherapy)

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25 pages, 473 KB

Open AccessEditor’s ChoiceReview

“Dusting Off the Cobwebs”: Rethinking How We Use New Antibiotics

by Jacob Myles Keck, Jacob Schultz and Alina Viteri

Antibiotics 2025, 14(9), 862; https://doi.org/10.3390/antibiotics14090862 - 27 Aug 2025

Cited by 1 | Viewed by 2084

Abstract

Antimicrobial resistance continues to escalate worldwide, threatening effective medical care, patient safety, and global health security. Traditional antibiotics are increasingly unreliable against multidrug-resistant pathogens, resulting in delayed appropriate therapy, prolonged illness, higher healthcare costs, and increased mortality. In this context, antimicrobial stewardship must [...] Read more.

Antimicrobial resistance continues to escalate worldwide, threatening effective medical care, patient safety, and global health security. Traditional antibiotics are increasingly unreliable against multidrug-resistant pathogens, resulting in delayed appropriate therapy, prolonged illness, higher healthcare costs, and increased mortality. In this context, antimicrobial stewardship must evolve beyond the preservation of older drugs to include the judicious, evidence-based use of newer antibiotics. When used empirically in high-risk scenarios, novel agents can improve clinical outcomes by ensuring timely, effective coverage against MDR organisms while reducing the need for broad-spectrum combinations that drive collateral resistance and adverse effects. A major challenge, however, is the underutilization of these agents, which not only limits patient benefit but also undermines incentives for continued pharmaceutical innovation. To address this gap, stewardship programs must incorporate strategies for appropriate empiric deployment of new antibiotics, guided by local epidemiology, risk stratification, rapid diagnostics, and multidisciplinary decision-making. A coordinated global effort, linking stewardship, innovation, and policy reform, will be critical to optimize the role of novel antimicrobials in clinical practice moving forward. Full article

(This article belongs to the Special Issue Revolutionizing Infection Treatment: Cutting-Edge Approaches in Antimicrobial Stewardship)

12 pages, 389 KB

Open AccessEditor’s ChoiceArticle

Evolution of Respiratory Pathogens and Antimicrobial Resistance over the COVID-19 Timeline: A Study of Hospitalized and Ambulatory Patient Populations

by Luigi Regenburgh De La Motte, Loredana Deflorio, Erika Stefano, Matteo Covi, Angela Uslenghi, Carmen Sommese and Lorenzo Drago

Antibiotics 2025, 14(8), 796; https://doi.org/10.3390/antibiotics14080796 - 5 Aug 2025

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Abstract

Background: The COVID-19 pandemic has profoundly altered the clinical and microbiological landscape of respiratory tract infections (RTIs), potentially reshaping pathogen distribution and antimicrobial resistance (AMR) profiles across care settings. Objectives: The objective of this study was to assess temporal trends in respiratory bacterial [...] Read more.

Background: The COVID-19 pandemic has profoundly altered the clinical and microbiological landscape of respiratory tract infections (RTIs), potentially reshaping pathogen distribution and antimicrobial resistance (AMR) profiles across care settings. Objectives: The objective of this study was to assess temporal trends in respiratory bacterial pathogens, antimicrobial resistance, and polymicrobial infections across three pandemic phases—pre-COVID (2018–2019), COVID (2020–2022), and post-COVID (2022–2024)—in hospitalized and ambulatory patients. Methods: We retrospectively analyzed 1827 respiratory bacterial isolates (hospitalized patients, n = 1032; ambulatory patients, n = 795) collected at a tertiary care center in Northern Italy. Data were stratified by care setting, anatomical site, and pandemic phase. Species identification and susceptibility testing followed EUCAST guidelines. Statistical analysis included chi-square and Fisher’s exact tests. Results: In hospitalized patients, a significant increase in Pseudomonas aeruginosa (from 45.5% pre-COVID to 58.6% post-COVID, p < 0.0001) and Acinetobacter baumannii (from 1.2% to 11.1% during COVID, p < 0.0001) was observed, with 100% extensively drug-resistant (XDR) rates for A. baumannii during the pandemic. Conversely, Staphylococcus aureus significantly declined from 23.6% pre-COVID to 13.7% post-COVID (p = 0.0012). In ambulatory patients, polymicrobial infections peaked at 41.2% during COVID, frequently involving co-isolation of Candida spp. Notably, resistance to benzylpenicillin in Streptococcus pneumoniae reached 80% (4/5 isolates) in hospitalized patients during COVID, and carbapenem-resistant P. aeruginosa (CRPA) significantly increased post-pandemic in ambulatory patients (0% pre-COVID vs. 23.5% post-COVID, p = 0.0014). Conclusions: The pandemic markedly shifted respiratory pathogen dynamics and resistance profiles, with distinct trends observed in hospital and community settings. Persistent resistance phenotypes and frequent polymicrobial infections, particularly involving Candida spp. in outpatients, underscore the need for targeted surveillance and antimicrobial stewardship strategies. Full article

(This article belongs to the Section Antibiotic Therapy in Infectious Diseases)

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23 pages, 1310 KB

Open AccessEditor’s ChoiceReview

Evaluating Antimicrobial Susceptibility Testing Methods for Cefiderocol: A Review and Expert Opinion on Current Practices and Future Directions

by Stefania Stefani, Fabio Arena, Luigi Principe, Stefano Stracquadanio, Chiara Vismara and Gian Maria Rossolini

Antibiotics 2025, 14(8), 760; https://doi.org/10.3390/antibiotics14080760 - 28 Jul 2025

Viewed by 3920

Abstract

Background: Cefiderocol (FDC) presents challenges in antimicrobial susceptibility testing (AST). The reference standard is the broth microdilution (BMD) method with iron-depleted cation-adjusted Mueller-Hinton broth (ID-CAMHB). Still, it is cumbersome for routine clinical laboratory use, while variable accuracy has been reported with available commercial [...] Read more.

Background: Cefiderocol (FDC) presents challenges in antimicrobial susceptibility testing (AST). The reference standard is the broth microdilution (BMD) method with iron-depleted cation-adjusted Mueller-Hinton broth (ID-CAMHB). Still, it is cumbersome for routine clinical laboratory use, while variable accuracy has been reported with available commercial systems. Variability in interpretive criteria and areas of technical uncertainty (ATUs) further complicate assessments. Methods: This review and expert opinion presents: (1) an overview of non-susceptibility to FDC and then delves into the performance of current FDC AST methods for Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii complex; (2) a practical decision framework to guide clinical microbiologists in making informed choices. Results and Conclusions: For Enterobacterales, including carbapenem-resistant Enterobacterales (CRE), and Pseudomonas aeruginosa, we propose disk diffusion (DD) as a preliminary screening tool to classify isolates as susceptible (S) or resistant (R). Confirmatory testing using the UMIC^® FDC system or the ID-CAMHB BMD method is recommended for R isolates. In cases of discrepancy, repeating the test with ID-CAMHB BMD is advised. Additionally, isolates falling within the ATU during DD testing should be retested using the UMIC^® system or ID-CAMHB BMD. For A. baumannii complex, since EUCAST breakpoints have not been defined yet, we propose a stepwise framework based on the first DD result: isolates with inhibition zones < 17 mm are considered non-susceptible and should be confirmed with standard BMD. Those between 17 and 22 mm require retesting with a commercial BMD method, with further confirmation recommended if S isolates with zones ≥ 23 mm may be considered S without additional testing. Full article

(This article belongs to the Special Issue Bacterial Detection, Identification, and Antimicrobial Susceptibility Testing)

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12 pages, 899 KB

Open AccessEditor’s ChoiceArticle

Antimicrobial Stewardship in Cardiac Device Surgery: Impact of Behavioural Change Interventions on Extended Prophylaxis Practices

by Li Wen Loo, Yvonne Peijun Zhou, Yi Bo Wang, Lai Wei Lee and Jasmine Shimin Chung

Antibiotics 2025, 14(8), 754; https://doi.org/10.3390/antibiotics14080754 - 25 Jul 2025

Viewed by 977

Abstract

Background/Objectives: Single-dose pre-operative antibiotic prophylaxis for cardiac-device implantation is recommended but extending antibiotic prophylaxis is common. Locally, 50–60% of patients had extended prophylaxis after pacemaker insertion or generator change. Our antimicrobial stewardship programme (ASP) incorporated behavioural change strategies in implementing a multi-pronged intervention [...] Read more.

Background/Objectives: Single-dose pre-operative antibiotic prophylaxis for cardiac-device implantation is recommended but extending antibiotic prophylaxis is common. Locally, 50–60% of patients had extended prophylaxis after pacemaker insertion or generator change. Our antimicrobial stewardship programme (ASP) incorporated behavioural change strategies in implementing a multi-pronged intervention bundle to address this and evaluated its effectiveness and safety. Methods: This single-centre, retrospective cohort study included patients aged 21 years old or older, undergoing uncomplicated pacemaker insertion or generator change at Singapore General Hospital (SGH) from October 2022 to March 2025. To improve antibiotic use, ASP interventions incorporating behaviour change strategies were implemented, namely (1) data-driven feedback, (2) targeted education, (3) identification and engagement of ASP champion, and (4) clinical pathway revision. Results: There were 779 patients evaluated; 380 (48.8%) received standard prophylaxis while 399 (51.2%) received extended prophylaxis with oral antibiotics (mean duration, 3.3 ± 0.8 days). Following ASP interventions, the practice of extended prophylaxis declined significantly from 43.8% to 24.0% (p < 0.01). The incidence of surgical site infections was low and similar in both groups (0.8%, p = 1.000); all infections were superficial. There was also significant reduction in the proportion of patients on all antibiotics from 20.7% to 16.3% (p < 0.01). Identification and engagement of ASP champion proved pivotal in changing prescribing behaviour through peer influence and credibility. Conclusions: The bundled ASP interventions, incorporating behavioural change strategies, have effectively and safely reduced the use of extended prophylaxis post-cardiac device implantation. Behavioural change interventions are essential to achieve sustained stewardship success. Full article

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21 pages, 594 KB

Open AccessEditor’s ChoiceArticle

Trends in Positive Urine Culture Rates and Antimicrobial Resistance in Non-Hospitalized Children from Western Romania: A Retrospective Observational Study

by Constantin Catalin Marc, Maria Daniela Mot, Monica Licker, Delia Muntean, Daniela Teodora Marti, Ana Alexandra Ardelean, Alina Ciceu, Sergiu Adrian Sprintar, Daniela Adriana Oatis, Alin Gabriel Mihu and Tudor Rares Olariu

Antibiotics 2025, 14(7), 723; https://doi.org/10.3390/antibiotics14070723 - 18 Jul 2025

Viewed by 2819

Abstract

Background: Urinary tract infections (UTIs) are among the most common types of infections during childhood. Limited data are available on the prevalence of UTI in children from Romania, with most being available for hospitalized children. For this reason, we conducted a retrospective observational [...] Read more.

Background: Urinary tract infections (UTIs) are among the most common types of infections during childhood. Limited data are available on the prevalence of UTI in children from Romania, with most being available for hospitalized children. For this reason, we conducted a retrospective observational study in consecutive non-hospitalized children to assess the number of positive UTI samples and the antibacterial resistance of causative pathogens. Methods: This study included 7222 consecutive urine cultures collected from children aged 1 to 18 years who are residents of Arad County, Western Romania. Urine samples were analyzed for leukocyturia and cultures for the presence of monomorphic bacteria. Results: The overall number of positive UTI samples was 10.44%. A higher number of positive UTI samples was observed in females when compared to males and in children aged 6–12 and 12 to 18 years when compared to those aged 1–5 years. The antibiotic susceptibility testing of E. coli isolates revealed high sensitivity to most tested antibacterials. Near-complete susceptibility was observed for fosfomycin (99.71%) and nitrofurantoin (96.01%), while high susceptibility rates were also observed for ciprofloxacin (85.43%) and amoxicillin–clavulanic acid (75.05%). In contrast, high resistance was found for ampicillin (62.28% resistant) and trimethoprim–sulfamethoxazole (36.53% resistant). Conclusions: Given the clinical risks associated with UTI in children, our findings underscore the urgent need for the continued monitoring of multidrug-resistant strains. Our study provides important epidemiological and resistance data to guide empirical treatment and strengthen pediatric antimicrobial resistance surveillance. Future studies should focus on different regions and regularly update resistance patterns to keep treatment and prevention strategies aligned with local conditions. Full article

(This article belongs to the Special Issue Prevalence, Treatment and Antibacterial Resistance of Urinary Tract Infections)

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33 pages, 1374 KB

Open AccessEditor’s ChoiceReview

Antimicrobials in Livestock Farming and Resistance: Public Health Implications

by Marilena Trinchera, Silvia De Gaetano, Elenoire Sole, Angelina Midiri, Serena Silvestro, Giuseppe Mancuso, Teresa Catalano and Carmelo Biondo

Antibiotics 2025, 14(6), 606; https://doi.org/10.3390/antibiotics14060606 - 14 Jun 2025

Cited by 4 | Viewed by 8706

Abstract

The accelerated spread of bacterial resistance has been demonstrated to reduce the effectiveness of antibiotic treatments for infections, resulting in higher morbidity and mortality rates, as well as increased costs for livestock producers. It is expected that the majority of future antimicrobial use [...] Read more.

The accelerated spread of bacterial resistance has been demonstrated to reduce the effectiveness of antibiotic treatments for infections, resulting in higher morbidity and mortality rates, as well as increased costs for livestock producers. It is expected that the majority of future antimicrobial use will be in animal production. The management of antimicrobial resistance (AMR) in the livestock sector poses significant challenges due to the multifaceted nature of the problem. In order to identify appropriate solutions to the rise of antimicrobial resistance, it is imperative that we have a comprehensive understanding of the disease dynamics underpinning the ways in which antimicrobial resistance is transmitted between humans and animals. Furthermore, in consideration of the anticipated requirement to satisfy the global demand for food, it is imperative that we guarantee that resistance is not transmitted or propagated during the treatment and disposal of animal waste, particularly from intensive farming. It is also crucial to formulate a research agenda to investigate how antibiotic resistance in animal faeces from livestock farming is affected by intensified farming activities. The review analyses the environment’s role in the transmission resistance chain and reviews methodologies for disrupting the link. A particular focus is placed on the limitations of the applied methodologies to reduce antimicrobial resistance in global animal production. Full article

(This article belongs to the Special Issue Livestock Antibiotic Use and Resistance)

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18 pages, 1231 KB

Open AccessEditor’s ChoiceArticle

The Genetic Background and Culture Medium Only Marginally Affect the In Vitro Evolution of Pseudomonas aeruginosa Toward Colistin Resistance

by Matteo Cervoni, Antonio Maria Ferriero, Alessandra Lo Sciuto, Francesca Guidi, Naida Babić Jordamović, Silvano Piazza, Olivier Jousson, Alfonso Esposito and Francesco Imperi

Antibiotics 2025, 14(6), 601; https://doi.org/10.3390/antibiotics14060601 - 13 Jun 2025

Viewed by 2116

Abstract

Background/Objectives: Colistin is a last-resort treatment for Pseudomonas aeruginosa multidrug-resistant infections, but resistance to it is emerging. While colistin resistance in P. aeruginosa is typically associated with chromosomal mutations inducing lipopolysaccharide (LPS) aminoarabinosylation, other mutations unrelated to LPS modifications have been proposed to [...] Read more.

Background/Objectives: Colistin is a last-resort treatment for Pseudomonas aeruginosa multidrug-resistant infections, but resistance to it is emerging. While colistin resistance in P. aeruginosa is typically associated with chromosomal mutations inducing lipopolysaccharide (LPS) aminoarabinosylation, other mutations unrelated to LPS modifications have been proposed to influence the extent of colistin resistance. Here, we examined whether the genetic background and culture conditions affect the evolution of high-level colistin resistance in this bacterium. Methods: We performed in vitro evolution experiments in the presence or absence of increasing colistin concentrations with two phylogenetically distant reference strains in a standard laboratory medium and in two media mimicking P. aeruginosa growth during lung or systemic infections. Resistance-associated mutations were identified by comparative genomics, and the role of selected mutated genes was validated by allele replacement, deletion, or conditional mutagenesis. Results: Most colistin-resistant mutants carried mutations in genes belonging to four functional groups: two-component systems controlling LPS aminoarabinosylation (PmrAB, PhoPQ), LPS biosynthesis, the production of the polyamine norspermidine, and fatty acid metabolism. No mutation was exclusively and invariably associated with a specific strain or medium. We demonstrated that norspermidine is detrimental to the acquisition of colistin resistance upon PmrAB activation and that impaired fatty acid biosynthesis can promote colistin resistance, even if it increases susceptibility to other antibiotics. Conclusions: The evolution of colistin resistance in P. aeruginosa appeared to be only marginally affected by the genetic background and culture conditions. Notably, mutations in fatty acid biosynthetic genes represent a newly identified genetic determinant of P. aeruginosa colistin resistance, warranting further investigation in clinical isolates. Full article

(This article belongs to the Special Issue Antibiotic Resistance and Virulence Mechanisms in Gram-Negative Bacteria: An Alliance for Success)

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14 pages, 1086 KB

Open AccessEditor’s ChoiceReview

Challenges of Carbapenem-Resistant Enterobacteriaceae in the Development of New β-Lactamase Inhibitors and Antibiotics

by Pierre Leroux, Charleric Bornet, Jean-Michel Bolla and Anita Cohen

Antibiotics 2025, 14(6), 587; https://doi.org/10.3390/antibiotics14060587 - 7 Jun 2025

Cited by 1 | Viewed by 2447

Abstract

Nowadays, antimicrobial resistance (AMR) is a growing global health threat, with carbapenem-resistant Enterobacteriaceae (CRE) posing particular concern due to limited treatment options. In fact, CRE have been classified as a critical priority by the World Health Organization (WHO). Carbapenem resistance results from complex [...] Read more.

Nowadays, antimicrobial resistance (AMR) is a growing global health threat, with carbapenem-resistant Enterobacteriaceae (CRE) posing particular concern due to limited treatment options. In fact, CRE have been classified as a critical priority by the World Health Organization (WHO). Carbapenem resistance results from complex mechanisms, often combining the production of hydrolytic enzymes such as β-lactamases with reduced membrane permeability and efflux system induction. The Ambler classification is an effective tool for differentiating the characteristics of serine-β-lactamases (SβLs) and metallo-β-lactamases (MβLs), including ESβLs (different from carbapenemases), KPC, NDM, VIM, IMP, AmpC (different from carbapenemases), and OXA-48. Recently approved inhibitor drugs, such as diazabicyclooctanones and boronic acid derivatives, only partially address this problem, not least because of their ineffectiveness against MβLs. However, compared with taniborbactam, xeruborbactam is the first bicyclic boronate in clinical development with a pan-β-lactamase inhibition spectrum, including the IMP subfamily. Recent studies explore strategies such as chemical optimization of β-lactamase inhibitor scaffolds, novel β-lactam/β-lactamase inhibitor combinations, and siderophore–antibiotic conjugates to enhance bacterial uptake. A deeper understanding of the mechanistic properties of the active sites enables rational drug design principles to be established for inhibitors targeting both SβLs and MβLs. This review aims to provide a comprehensive overview of current therapeutic strategies and future perspectives for the development of carbapenemase inhibitor drug candidates. Full article

(This article belongs to the Special Issue Discovery and Synthesis of Antimicrobial Compounds Against Multidrug Resistance)

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21 pages, 7339 KB

Open AccessEditor’s ChoiceArticle

In Vitro Analysis of Interactions Between Staphylococcus aureus and Pseudomonas aeruginosa During Biofilm Formation

by Julia Scaffo, Rayssa Durães Lima, Cameron Dobrotka, Tainara A. N. Ribeiro, Renata F. A. Pereira, Daniela Sachs, Rosana B. R. Ferreira and Fabio Aguiar-Alves

Antibiotics 2025, 14(5), 504; https://doi.org/10.3390/antibiotics14050504 - 14 May 2025

Cited by 3 | Viewed by 3615

Abstract

Staphylococcus aureus and Pseudomonas aeruginosa are classified as ESKAPE pathogens that present a significant challenge to treatment due to their increased resistance to a considerable number of antimicrobial agents. Background/Objective: Biofilms exacerbate treatment challenges by providing enhanced antimicrobial and environmental protection. Mixed-species [...] Read more.

Staphylococcus aureus and Pseudomonas aeruginosa are classified as ESKAPE pathogens that present a significant challenge to treatment due to their increased resistance to a considerable number of antimicrobial agents. Background/Objective: Biofilms exacerbate treatment challenges by providing enhanced antimicrobial and environmental protection. Mixed-species biofilms further complicate treatment options through numerous complex interspecies interactions, leading to potentially severe adverse clinical outcomes. Methods: This study assessed the interaction between clinical S. aureus and P. aeruginosa isolates during biofilm formation using microplate biofilm formation assays, scanning electron microscopy, and confocal microscopy. Results: We identified a competitive relationship between P. aeruginosa and S. aureus, where both pathogens exhibited a reduction in biofilm formation during mixed-species biofilms compared with monocultures, although P. aeruginosa outcompeted S. aureus. Furthermore, we found that the cell-free conditioned media (CFCM) of P. aeruginosa significantly reduced the S. aureus biofilms. Using fractioned CFCM, we identified that the anti-staphylococcal activity of the >10 kDa fraction was almost identical to the non-fractioned CFCM. Our confocal microscopy results suggest that P. aeruginosa CFCM depolarize S. aureus membranes and reduces the biofilm burden. Conclusions: These findings contribute to our understanding of the mechanisms underlying the interactions between these pathogens, suggesting that there is an antagonistic relationship between S. aureus and P. aeruginosa in a biofilm setting. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in Biofilm-Associated Infections)

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15 pages, 7498 KB

Open AccessEditor’s ChoiceArticle

Lack of Spontaneous and Adaptive Resistance Development in Staphylococcus aureus Against the Antimicrobial Peptide LTX-109

by Bhupender Singh, Mia Angelique Winkler, Wasifa Kabir, Johanna U Ericson and Arnfinn Sundsfjord

Antibiotics 2025, 14(5), 492; https://doi.org/10.3390/antibiotics14050492 - 11 May 2025

Viewed by 1439

Abstract

Nasal carriage of Staphylococcus aureus and its antibiotic-resistant derivative, methicillin-resistant S. aureus (MRSA), is a risk factor for nosocomial S. aureus infections. Mupirocin is a topical antibiotic and a key in the decolonization of both methicillin-susceptible S. aureus (MSSA) and MRSA carriage in [...] Read more.

Nasal carriage of Staphylococcus aureus and its antibiotic-resistant derivative, methicillin-resistant S. aureus (MRSA), is a risk factor for nosocomial S. aureus infections. Mupirocin is a topical antibiotic and a key in the decolonization of both methicillin-susceptible S. aureus (MSSA) and MRSA carriage in patients and health care personnel. Recent observations have shown a global increase in the prevalence of mupirocin-resistant MSSA and MRSA, reducing the efficacy of mupirocin in decolonization regimens. LTX-109 is a peptidomimetic synthetic compound that has shown broad-spectrum bactericidal antimicrobial activity in vitro and in animal experiments. However, the development of resistance against LTX-109 in clinical isolates of MRSA and MSSA has not been systematically examined. Background/Objectives: Here, we assess the development of spontaneous and adaptive resistance against LTX-109 in genomically diverse MRSA (n = 3) and MSSA (n = 4) strains. Methods: Adaptive and mutational resistance were examined by serial passaging strains over 60 cycles in a range of LTX-109 and mupirocin concentrations. Spontaneous resistance was examined in high-inoculum agar plates with 2–8 times the concentration above MIC. Results: Throughout serial passage, LTX-109 MICs varied less than 4-fold compared to the initial MIC of 4–8 mg/L, while mupirocin MICs increased in all susceptible strains (n = 5) from 0.25 mg/L to 16–512 mg/L. The spontaneous resistance assay demonstrated no resistance development at 4–8× MIC LTX-109 and an inoculum effect at 2× MIC. Conclusions: Our results demonstrate the novelty of LTX-109 as an antimicrobial agent with no detectable in vitro resistance development in selected clinical strains of MRSA and MSSA. Full article

(This article belongs to the Special Issue Strategies for Combatting Multidrug-Resistant and Extensively Drug-Resistant Bacteria, 2nd Edition)

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25 pages, 11534 KB

Open AccessEditor’s ChoiceArticle

Repurposing Mouthwashes: Antifungal and Antibiofilm Abilities of Commercially Available Mouthwashes Against Candida spp.

by Marie Maziere, Paulo Rompante, José Carlos Andrade, Beatriz S. F. De Oliveira, Mariana C. Alves and Celia Fortuna Rodrigues

Antibiotics 2025, 14(5), 483; https://doi.org/10.3390/antibiotics14050483 - 9 May 2025

Cited by 2 | Viewed by 2332

Abstract

Background/Objectives: The main objective was to evaluate and compare the antifungal efficacy against Candida spp. in commercially available mouthwashes distributed in the European market. Indeed, the solution to emerging infectious diseases may no longer lie in costly new drug development but rather [...] Read more.

Background/Objectives: The main objective was to evaluate and compare the antifungal efficacy against Candida spp. in commercially available mouthwashes distributed in the European market. Indeed, the solution to emerging infectious diseases may no longer lie in costly new drug development but rather in unlocking the untapped potential of existing substances. Materials and Methods: Eighteen mouthwashes, chosen based on their composition, were tested in vitro against ten Candida strains, including clinical isolates of oral origin and reference strains, in both planktonic and biofilm forms. The antifungal susceptibility testing was conducted using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disc diffusion method and the evaluation of the kinetic growth in planktonic Candida. Biofilm reduction was determined by the evaluation of the minimal biofilm eradication concentration (MBEC). Scanning electron microscopy (SEM) analysis was performed to evaluate potential morphological alterations of Candida biofilms. Results: Most mouthwashes effectively reduced biomass production and colony-forming unit (CFU) count. Parodontax Extra showed the highest efficacy. In the disc diffusion assay, Gum Paroex 0.12% exhibited the largest average inhibition zone diameter. Some unusual trends in the data may be explained by a higher reaction of fungal cells and the release of excess biomass during co-incubation in higher concentration of mouthwashes. SEM images revealed significant morphological alterations. Conclusion: Mouthwashes containing chlorhexidine digluconate, either alone or in combination with cetylpyridinium chloride and other active compounds, emerged as a common factor among the most efficacious formulations. In vivo studies will be essential to validate these findings, but mouthwashes may serve as a valuable adjuvant in the treatment of oral candidiasis. Full article

(This article belongs to the Special Issue Microbial Biofilms: Identification, Resistance and Novel Drugs)

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12 pages, 248 KB

Open AccessEditor’s ChoiceArticle

An Outbreak of Serratia marcescens in a Cardiothoracic Surgery Unit Associated with an Infected Solution of Pre-Prepared Syringes

by Maria Papagianni, Eleni Mylona, Sofia Kostourou, Chrysoula Kolokotroni, Dimitris Kounatidis, Natalia G. Vallianou and Vasileios Papastamopoulos

Antibiotics 2025, 14(3), 319; https://doi.org/10.3390/antibiotics14030319 - 18 Mar 2025

Viewed by 2551

Abstract

Background/Objectives: The aim of the present study is to report an outbreak of bloodstream infections caused by Serratia marcescens in patients undergoing postoperational procedures in the Cardiothoracic Department and to describe the epidemiological investigations and control measures undertaken. A cluster of bacteremia due [...] Read more.

Background/Objectives: The aim of the present study is to report an outbreak of bloodstream infections caused by Serratia marcescens in patients undergoing postoperational procedures in the Cardiothoracic Department and to describe the epidemiological investigations and control measures undertaken. A cluster of bacteremia due to Serratia marcescens was identified in blood cultures from postoperative patients in the Cardiothoracic Surgery Department in November 2023. Methods: Active surveillance by the hospital’s prevention and control team was initiated. Interviews with nurses and sanitary personnel and reviews of the most common procedures, such as hand washing, bladder catheterization, and intravenous catheter care, were performed. Culturing samples from hospital personnel, postoperative patients, and the environment, including pressure transducers, tap water, soap, therapeutic solutions, antiseptics, respirators, and various intravenous preparations, were drawn up. Overall, 225 samples were collected, including 149 blood cultures, and these were all sent to the Hospital’s Microbiology Laboratory. Results: Twenty-three out of forty-seven postoperative patients had positive blood cultures for Serratia marcescens. All the postoperative patients involved in the outbreak received cefepime according to antimicrobial susceptibility testing. Three pre-prepared flushing syringes were found to be positive for Serratia marcescens as well. The Cardiothoracic Department was kept under surveillance with hand hygiene measures, infusion preparation, medical device use, and cleaning procedures reviewed by the infection’s prevention and control team. Conclusions: Undoubtedly, nosocomial outbreaks represent an important health issue regarding morbidity, mortality, and costs. Timely interventions by the hospital’s infection prevention and control team may be life-saving under these circumstances. Full article

(This article belongs to the Special Issue Epidemiology, Diagnosis and Antimicrobial Treatment of Hospital-Acquired Infections)

24 pages, 7266 KB

Open AccessEditor’s ChoiceArticle

A Simple In Vitro Method to Determine Bactericidal Activity Against Mycobacterium abscessus Under Hypoxic Conditions

by Ruth Feilcke, Robert Eckenstaler, Markus Lang, Adrian Richter and Peter Imming

Antibiotics 2025, 14(3), 299; https://doi.org/10.3390/antibiotics14030299 - 13 Mar 2025

Cited by 1 | Viewed by 1814

Abstract

Background/Objectives: Non-replicating persisters (NRPs) of Mycobacterium abscessus are a bacterial subpopulation that can survive in the host under unfavorable conditions, such as hypoxia or nutrient starvation. The eradication of these bacteria is difficult, which is one reason for the long treatment duration [...] Read more.

Background/Objectives: Non-replicating persisters (NRPs) of Mycobacterium abscessus are a bacterial subpopulation that can survive in the host under unfavorable conditions, such as hypoxia or nutrient starvation. The eradication of these bacteria is difficult, which is one reason for the long treatment duration and treatment failure. The drug discovery process should therefore contain methods to screen activity against NRPs. Methods: A hypoxic environment is used to generate NRPs of M. abscessus that are termed low-oxygen persisters (LOPs). For this, an oxidation process is used to transition a replicating culture of M. abscessus distributed in microtiter plates within a sealable box into LOPs. Colony counting, automated object counting, bactericidal activity determination of known agents, and confocal laser scanning microscopy are used to study the obtained culture. Results: The obtained culture shows typical attributes of non-replicating cells, such as significantly reduced replication, the reversibility of the LOP state under aerobic conditions, delayed regrowth on solid medium, altered morphological patterns on a single-cell level, and phenotypical resistance against a variety of clinically relevant antimycobacterial compounds. The study reveals metronidazole and niclosamide as bactericidal against M. abscessus LOPs. These compounds can be used as LOP verification compounds within the described model. Conclusions: Our model is easily implemented and quickly identifies compounds that are inactive under hypoxic conditions. It can therefore accelerate the identification of clinically effective antimycobacterial drug substances, and can be a helpful tool during the drug development process. Full article

(This article belongs to the Section Antibiotic Therapy in Infectious Diseases)

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14 pages, 2459 KB

Open AccessEditor’s ChoiceArticle

Antibacterial and Antibiofilm Activities of Hydralazine, an Antihypertensive Drug: In Vitro and In Silico Approaches

by Antônio Mateus Gomes Pereira, Benise Ferreira da Silva, Ingrid Maria Frota Araujo, Francisco Kauê Carvalho Aguiar, Paulo Adenes Teixeira Coelho, Renata Albuquerque Costa, Marcia Machado Marinho, Emmanuel Silva Marinho, João Victor Serra Nunes, Victor Alves Carneiro and Hélcio Silva dos Santos

Antibiotics 2025, 14(3), 286; https://doi.org/10.3390/antibiotics14030286 - 10 Mar 2025

Cited by 1 | Viewed by 1809

Abstract

Background: The rise of multidrug-resistant (MDR) bacteria poses a significant challenge to global public health, contributing to increased morbidity and mortality rates. In this context, the repurposing of existing drugs has emerged as a promising strategy. In this study, hydralazine (HDZ), a vasodilator [...] Read more.

Background: The rise of multidrug-resistant (MDR) bacteria poses a significant challenge to global public health, contributing to increased morbidity and mortality rates. In this context, the repurposing of existing drugs has emerged as a promising strategy. In this study, hydralazine (HDZ), a vasodilator used as an antihypertensive since 1952, demonstrated antibacterial and antibiofilm activity against both Gram-positive and Gram-negative bacteria. Methods: In this study, the antibacterial activity of the antihypertensive hydralazine (HDZ) was evaluated against Gram-positive and Gram-negative strains through minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), growth curve with MIC and sub-MIC doses, combinatorial effect with gentamicin, scanning electron microscopy (SEM), molecular docking, and antibiofilm activity. Results: The MIC and MBC values ranged from 39.5 to 1.250 μg/mL, respectively. A change in the growth kinetics of the strains was observed when exposed to MIC and 1/2 MIC values, with a delay in the phases of up to 12 h. The combinatorial effect with gentamicin demonstrated an additive and indifferent potential when combined with HDZ. Conclusions: Furthermore, hydralazine showed antibiofilm activity against the tested strains, including MRSA. Electron microscopy analysis revealed significant changes in bacterial morphology when exposed to the MIC dose of HDZ for 4 h. The overall results of the study indicate hydralazine as a potential agent in the fight against bacterial infections. Full article

(This article belongs to the Special Issue Repositioning Drugs as a Strategy to Combat Infections)

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19 pages, 1580 KB

Open AccessEditor’s ChoiceArticle

Fitness Burden for the Stepwise Acquisition of First- and Second-Line Antimicrobial Reduced-Susceptibility in High-Risk ESKAPE MRSA Superbugs

by Eleonora Chines, Gaia Vertillo Aluisio, Maria Santagati, Maria Lina Mezzatesta and Viviana Cafiso

Antibiotics 2025, 14(3), 244; https://doi.org/10.3390/antibiotics14030244 - 28 Feb 2025

Cited by 1 | Viewed by 3124

Abstract

Background: The fitness costs (FCs) of antimicrobial resistance (AMR) are crucial issues in antimicrobial resistance (AMR) onset, spread, and, consequently, public health. In Staphylococcus aureus, AMR can induce significant FCs due to slow growth, low competitiveness, and virulence. Here, we investigated the [...] Read more.

Background: The fitness costs (FCs) of antimicrobial resistance (AMR) are crucial issues in antimicrobial resistance (AMR) onset, spread, and, consequently, public health. In Staphylococcus aureus, AMR can induce significant FCs due to slow growth, low competitiveness, and virulence. Here, we investigated the genomics and FCs emerging for progressively acquiring daptomycin (DAP) and glycopeptide (GLY) reduced susceptibility in MRSA. Methods: Genomics was carried out using Illumina-MiSeq Whole-genome sequencing and bioinformatics. The biological FCs of isogenic MRSA strain pairs progressively acquiring DAP and GLY-reduced susceptibility, under DAP/GLY mono or combined therapy, were performed by in-vitro independent and competitive mixed growth, phenotypic in-vitro virulence analysis, and in-vivo G. mellonella larvae killing. Results: Genomics evidenced four different extremely resistant high-risk clones, i.e., ST-5 N315 HA-MRSA, ST-398 LA-MRSA, ST-22 USA-100 HA-EMRSA-15, and ST-1 MW2 CA-MRSA. In-vitro fitness assays revealed slow growth, lower competitiveness, and reduced virulence, predominantly in Galleria mellonella killing ability, in DAP-S hGISA, DAP-R GSSA, DAP-R hGISA, and DAP-R GISA strains. Conclusions: The occurrence of glycopeptide and daptomycin reduced susceptibility conferred increasing FCs, paid as a gradual reduction in virulence, competitiveness, and slow growth performance. Full article

(This article belongs to the Special Issue Spread of Multidrug-Resistant Microorganisms, 2nd Edition)

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12 pages, 545 KB

Open AccessEditor’s ChoiceArticle

Evaluation of the Use of Preventive Antibiotic Therapy in Patients Undergoing One-Step Prosthetic Revision Surgery with Low Preoperative Infectious Risk

by Leonardo Motta, Giacomo Stroffolini, Stefania Marocco, Giulia Bertoli, Gianluca Piovan, Lorenzo Povegliano, Claudio Zorzi and Federico Gobbi

Antibiotics 2025, 14(3), 224; https://doi.org/10.3390/antibiotics14030224 - 21 Feb 2025

Viewed by 1244

Abstract

Introduction: The prosthetic knee infection (PKI) rate in most centers ranges from 0.5 to 2% for knee replacements, depending on risk factors. Current PKI definitions may miss the identification of both early and late complications. There is no consensus on preventive or early [...] Read more.

Introduction: The prosthetic knee infection (PKI) rate in most centers ranges from 0.5 to 2% for knee replacements, depending on risk factors. Current PKI definitions may miss the identification of both early and late complications. There is no consensus on preventive or early empiric antibiotic therapy (EEAT) in the one-step exchange strategy for low-risk patients pending microbiology results. The aim of the study was to evaluate the potential role of EEAT in patients with comorbidities in preventing PKI and to evaluate differences in septic failure at 3, 6 and 9 months after prosthetic revision between patients undergoing EEAT and patients not undergoing EEAT. Methods: All adult patients undergoing one-step knee revision surgery at IRCCS Sacro-Cuore Don Calabria Negrar, from January 2018 to February 2021, were retrospectively included in a cohort observational study. Patients on antibiotic therapy before surgery or with preoperative ascertained PKI were excluded. Demographic characteristics, Charlson score, comorbidities, inflammatory markers, microbiological tests, imaging, infectious disease risk score and EEAT data were collected. Any postoperative complication or modification of antibiotic therapy at 14, 30, 90, 180 and 270 days after surgery was collected. Results: A total of 227 patients were included: 114 comorbid low-risk patients received EEAT after surgery, pending microbiological results; while 113 non-comorbid low-risk patients did not receive any antibiotic therapy in the postoperative period. Among the EEAT group, 16 were diagnosed with PKI, compared with 10 in the untreated group. Regarding septic failure during the 9-month follow-up after revision surgery, we registered nine cases in the EEAT arm and four in the untreated arm. In three out of nine cases treated with EEAT who had a post-revision septic failure, the causative microorganism was not successfully empirically targeted by EEAT; in the untreated group, two out of four cases had a post-revision septic failure, despite the targeted treatment of intraoperatively identified causative microorganisms. Conclusions: According to our results, EEAT after revision surgery in patients with comorbidities, who are at higher risk of infection, did not prevent prosthetic knee infections. There was also no evidence of a reduction in subsequent septic failure within nine months of revision surgery between groups. More accurate risk-defining scores are needed to identify patients at risk of PKI complications. Full article

(This article belongs to the Special Issue Epidemiology, Diagnosis and Antimicrobial Treatment of Hospital-Acquired Infections)

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13 pages, 218 KB

Open AccessEditor’s ChoiceArticle

Predictive Factors for Risk of Reinfection in Septic Two-Stage Revision of Total Hip and Knee Arthroplasties

by Benedikt Paul Blersch, Florian Hubert Sax, Philipp Schuster and Bernd Fink

Antibiotics 2025, 14(2), 167; https://doi.org/10.3390/antibiotics14020167 - 8 Feb 2025

Cited by 1 | Viewed by 1207

Abstract

Background: The two-stage septic exchange is the most common therapy concept in the treatment of periprosthetic hip and knee infections. However, before the second-stage reimplantation can be carried out, the physician has to assess whether or not the eradication of the periprosthetic joint [...] Read more.

Background: The two-stage septic exchange is the most common therapy concept in the treatment of periprosthetic hip and knee infections. However, before the second-stage reimplantation can be carried out, the physician has to assess whether or not the eradication of the periprosthetic joint infection (PJI) has been successful. Therefore, the aim of this study was to evaluate possible predictive parameters for the successful treatment of PJI before and at the time of reimplantation. Methods: This study investigated a total of 145 patients with periprosthetic hip infection and 93 patients with periprosthetic knee infection, who all underwent a two-stage septic exchange between 2017 and 2021. In order to identify possible risk factors for reinfections, the patients underwent preoperative examination of serological inflammatory parameters, microbiological and histological examination of the periprosthetic membrane at the time of reimplantation, as well as postoperative evaluations at regular intervals for a period of at least 24 months. Results: During the follow-up period, reinfection occurred in 11.3% of cases after the two-stage septic revision. None of the serological, microbiological, or histological parameters were able to significantly predict the risk of reinfection. Risk factors associated with reinfection were BMI and previous revision surgery. Conclusions: Currently, there is no reliable predictive factor indicating the risk of reinfection at the time of reimplantation. New diagnostic methods need to be developed to evaluate the possibility and timing of endoprosthesis reimplantation. Full article

(This article belongs to the Special Issue Prevention, Diagnostic and Antibiotic Treatment of Periprosthetic Joint and Fracture Related Infection, 2nd Edition)

17 pages, 7112 KB

Open AccessEditor’s ChoiceArticle

Antimicrobial and Antibiofilm Activity of Auranofin and Its Two Derivatives Bearing Naproxen and Acetylcysteine as Ligands Against Staphylococci

by Caterina Ferretti, Lorenzo Chiaverini, Noemi Poma, Andrea Dalli, Riccardo Di Leo, Laura Rindi, Alessandro Marrone, Iogann Tolbatov, Diego La Mendola, Arianna Tavanti, Tiziano Marzo and Mariagrazia Di Luca

Antibiotics 2025, 14(2), 118; https://doi.org/10.3390/antibiotics14020118 - 23 Jan 2025

Cited by 2 | Viewed by 2132

Abstract

Background/Objectives: The ability of bacteria to form biofilms makes them more tolerant to traditional antibiotics. Given the lack of new antibiotic development, drug repurposing offers a strategy for discovering new treatments. Auranofin (AF), a gold-based compound indicated for the treatment of rheumatoid [...] Read more.

Background/Objectives: The ability of bacteria to form biofilms makes them more tolerant to traditional antibiotics. Given the lack of new antibiotic development, drug repurposing offers a strategy for discovering new treatments. Auranofin (AF), a gold-based compound indicated for the treatment of rheumatoid arthritis, shows promising antibacterial activity. This study investigates the antimicrobial and antibiofilm activity of AF and its two derivatives in which the thiosugar ligand is replaced by acetylcysteine (AF-AcCys) or naproxen (AF-Napx), against Staphylococcus aureus and Staphylococcus epidermidis. Methods: AF was conjugated by transmetalation with either naproxen or acetylcysteine. Assessments of their stability in DMSO/H₂O and lipophilicity expressed as the LogP were performed. The antimicrobial activity of AF and its analogues were investigated by broth microdilution assay to determine the minimum inhibitory concentration (MIC) and versus biofilm to obtain the minimum bactericidal biofilm concentration (MBBC) and minimum biofilm eradication concentration (MBEC). Results: AF derivatives were found to be stable in a DMSO/H₂O mixture for 48 h. AF-Napx showed a LogP = 1.25 ± 0.22, close to AF, while AF-AcCys had a LogP = −0.95. MIC values of S. aureus and S. epidermidis were ranging from 2 µM to 0.25 µM, and ≤0.12 µM, respectively. Both AF and AF-Napx maintained efficacy against biofilm-embedded S. aureus and S. epidermidis at non-cytotoxic concentrations, with AF-Napx demonstrating lower MBBC values for S. epidermidis. Conclusions: AF, and especially its naproxen conjugate, holds potential as a therapeutic agent for treating biofilm-associated infections caused by S. aureus and S. epidermidis, particularly in device-related infections where both infection and inflammation are present. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Evolution and New Strategies to Fight It)

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17 pages, 1902 KB

Open AccessEditor’s ChoiceArticle

Controlling Oral Polymicrobial Biofilm Using Usnic Acid on the Surface of Titanium in the Artificial Saliva Media

by Nazia Tabassum, Fazlurrahman Khan, Geum-Jae Jeong, Do Kyung Oh and Young-Mog Kim

Antibiotics 2025, 14(2), 115; https://doi.org/10.3390/antibiotics14020115 - 22 Jan 2025

Viewed by 2381

Abstract

Background/Objectives: Titanium dental implants, while highly successful, face challenges due to polymicrobial infections leading to peri-implantitis and implant failure. Biofilm formation on implant surfaces is the primary cause of these infections, with factors such as matrix production and cross-kingdom interactions contributing to the [...] Read more.

Background/Objectives: Titanium dental implants, while highly successful, face challenges due to polymicrobial infections leading to peri-implantitis and implant failure. Biofilm formation on implant surfaces is the primary cause of these infections, with factors such as matrix production and cross-kingdom interactions contributing to the microbial accumulation of bacterial and fungal pathogens species. To combat this issue, naturally derived molecules have been reported to overcome the hurdle of antimicrobial resistance against the application of conventional antibiotics and antifungals. Methods: The present study aimed to employ the lichen-derived molecules, usnic acid (UA), to retard the development of biofilms of bacterial and fungal pathogens on the surface of titanium kept in the human artificial saliva (HAS) working as a growth-supporting, host-mimicking media. Results: The minimum inhibitory concentration of UA in HAS towards Candida albicans was >512 µg/mL, whereas against Staphylococcus aureus and Streptococcus mutans, it was determined to be 512 µg/mL. Whereas, in the standard growth media, the MIC value of UA towards S. mutans and S. aureus were 8 and 16 µg/mL; however, against C. albicans, it was 512 µg/mL. UA synergistically enhanced the efficacy of the antibiotics toward bacterial pathogens and the efficacy of antifungals against C. albicans. The antibiofilm results depict the fact that in the HAS, UA significantly reduced both mono-species of S. mutans, S. aureus, and C. albicans and mixed-species biofilm of C. albicans with S. mutans and S. aureus on the surface of the titanium. Conclusions: The present study showed that UA is a promising natural drug that can control oral polymicrobial disease as a result of the application of dental implants. Full article

(This article belongs to the Special Issue Strategies for Combatting Multidrug-Resistant and Extensively Drug-Resistant Bacteria, 2nd Edition)

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17 pages, 5886 KB

Open AccessEditor’s ChoiceArticle

Interference of Celastrol with Cell Wall Synthesis and Biofilm Formation in Staphylococcus epidermidis

by Leandro de León Guerra, Nayely Padilla Montaño and Laila Moujir

Antibiotics 2025, 14(1), 26; https://doi.org/10.3390/antibiotics14010026 - 3 Jan 2025

Cited by 1 | Viewed by 1788

Abstract

Background: The emergence of antibiotic-resistant bacteria, including Staphylococcus epidermidis, underscores the need for novel antimicrobial agents. Celastrol, a natural compound derived from the plants of the Celastraceae family, has demonstrated promising antibacterial and antibiofilm properties against various pathogens. Objectives: This study [...] Read more.

Background: The emergence of antibiotic-resistant bacteria, including Staphylococcus epidermidis, underscores the need for novel antimicrobial agents. Celastrol, a natural compound derived from the plants of the Celastraceae family, has demonstrated promising antibacterial and antibiofilm properties against various pathogens. Objectives: This study aims to evaluate the antibacterial effects, mechanism of action, and antibiofilm activity of celastrol against S. epidermidis, an emerging opportunistic pathogen. Methods: To investigate the mechanism of action of celastrol, its antibacterial activity was evaluated by determining the time–kill curves, assessing macromolecular synthesis, and analysing its impact on the stability and functionality of the bacterial cell membrane. Additionally, its effect on biofilm formation and disruption was examined. Results: Celastrol exhibited significant antibacterial activity with a minimal inhibitory concentration (MIC) of 0.31 μg/mL and minimal bactericidal concentration (MBC) of 15 μg/mL, which is superior to conventional antibiotics used as control. Time–kill assays revealed a concentration-dependent bactericidal effect, with a shift from bacteriostatic activity at lower concentrations to bactericidal and lytic effect at higher concentrations. Celastrol inhibited cell wall biosynthesis by blocking the incorporation of N-acetylglucosamine (NAG) into peptidoglycan. In contrast, the cytoplasmic membrane was only affected at higher concentrations of the compound or after prolonged exposure times. Additionally, celastrol was able to disrupt biofilm formation at concentrations of 0.9 μg/mL and to eradicate pre-formed biofilms at 7.5 μg/mL in S. epidermidis. Conclusions: Celastrol exhibits significant antibacterial and antibiofilm activities against S. epidermidis, with a primary action on cell wall synthesis. Its efficacy in disrupting the formation of biofilms and pre-formed biofilms suggests its potential as a therapeutic agent for infections caused by biofilm-forming S. epidermidis resistant to conventional treatments. Full article

(This article belongs to the Special Issue Antimicrobial and Antibiofilm Activity by Natural Compounds)

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20 pages, 2256 KB

Open AccessEditor’s ChoiceArticle

Tracking the Prevalence of Antibiotic Resistance in Enterococcus Within the Spanish Poultry Industry: Insights from a One Health Approach

by Josep Garcia-Llorens, Isaac Monroy, Jan Torres-Boncompte, Jose M. Soriano, Pablo Catalá-Gregori and Sandra Sevilla-Navarro

Antibiotics 2025, 14(1), 16; https://doi.org/10.3390/antibiotics14010016 - 30 Dec 2024

Cited by 3 | Viewed by 3087

Abstract

Background/Objectives: Antimicrobial resistance (AMR) in Enterococcus species from poultry production represents a significant public health threat due to the potential transmission of AMR through the food chain. This study aimed to examine the relative prevalence, resistance patterns, and mannitol fermentation [...] Read more.

Background/Objectives: Antimicrobial resistance (AMR) in Enterococcus species from poultry production represents a significant public health threat due to the potential transmission of AMR through the food chain. This study aimed to examine the relative prevalence, resistance patterns, and mannitol fermentation capacity of Enterococcus isolates from various poultry production systems in Spain over a seven-year period (2017–2023). Methods: A total of 215 Enterococcus isolates were analyzed. Phenotypic assessments were conducted to determine resistance rates and metabolic capacities, while genotypic characterization focused on detecting vancomycin-resistance genes (vanA, vanB, vanC, and vanD). Results: Enterococcus faecalis (62.3%) and Enterococcus faecium (29.77%) were the predominant species, primarily isolated from broilers (74.88%), with the highest frequency observed in one-week-old chicks (31.16%). High resistance rates to tetracyclines and streptogramins were identified, while resistance to vancomycin (0.47%) and tigecycline (3.03%) was low. Interestingly, a significant reduction in tetracyclines resistance was shown in this period for Enterococcus faecalis (from 100% to 70% (2017–2023) and Enterococcus faecium (from 100% to 40% (2018–2023)). Multidrug resistance (MDR) was detected in 26.98% of isolates. Mannitol fermentation tests revealed high metabolic capacity in Enterococcus faecalis (99.25%) and Enterococcus faecium (96.88%), associated with adaptability and virulence potential. Genotypic analysis showed a very low prevalence of vanB and vanC genes. Conclusions: These findings highlight the critical need for targeted surveillance and intervention strategies in poultry production to mitigate the risks posed by MDR Enterococcus to public health. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in One Health Perspective: New Insights in Human, Animal, and Environment Interlace, 2nd Edition)

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10 pages, 195 KB

Open AccessEditor’s ChoiceArticle

Safety and Effectiveness of BPaL-Based Regimens to Treat Multidrug-Resistant TB: First Experience of an Italian Tuberculosis Referral Hospital

by Gina Gualano, Maria Musso, Paola Mencarini, Silvia Mosti, Carlotta Cerva, Pietro Vittozzi, Antonio Mazzarelli, Angela Cannas, Assunta Navarra, Stefania Ianniello, Paolo Faccendini and Fabrizio Palmieri

Antibiotics 2025, 14(1), 7; https://doi.org/10.3390/antibiotics14010007 - 25 Dec 2024

Cited by 2 | Viewed by 3969

Abstract

Background/Objectives: Tuberculosis (TB) is preventable and curable, but multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) pose significant challenges worldwide due to the limited treatment options, lengths of therapies, and high rates of treatment failure. The management of MDR-TB has been revolutionized [...] Read more.

Background/Objectives: Tuberculosis (TB) is preventable and curable, but multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) pose significant challenges worldwide due to the limited treatment options, lengths of therapies, and high rates of treatment failure. The management of MDR-TB has been revolutionized by all oral anti-TB drug regimens that are likely to improve adherence and treatment outcomes. These regimes include bedaquiline (B), pretomanid (P), and linezolid (L) (BPaL), and moxifloxacin if resistance to fluoroquinolones is not detected (BPaLM). Based on the evidence generated by the TB-PRACTECAL and ZeNix randomized controlled trials, BPaL/BPaLM regimens are recommended over the currently recommended longer regimens in patients with MDR-TB or monoresistance to rifampin (RR). To our knowledge, no data are currently available on the implementation of BPaL/BPaLM regimens in Italy. Results: Seventeen patients completed the BPaL/BPaLM regimen, with a treatment success rate of 90% (17/19), consistent with the literature data. Eleven patients out of the nineteen retained in care (58%) complained about symptoms consistent with adverse events (AEs). No treatment interruption was necessary due to AEs. Methods: Here, we report the real-world experience of a tertiary referral hospital for TB in Italy, from 2022 to 2024, in the management, outcomes, and adverse drug reactions of a cohort of twenty-two MDR/RR patients treated with BPaL and BPaLM regimens. Conclusions: BPaL-containing regimens also serve as promising options for patients with RR/MDR-TB in terms of real-life experience, but further multicentric studies are required in Europe to confirm the efficacy of shorter regimens to eliminate MDR TB. Full article

(This article belongs to the Special Issue Antibiotics Use for Respiratory Diseases)

17 pages, 631 KB

Open AccessEditor’s ChoiceArticle

Pooled Antibiotic Susceptibility Testing Performs Within CLSI Standards for Validation When Measured Against Broth Microdilution and Disk Diffusion Antibiotic Susceptibility Testing of Cultured Isolates

by Emery Haley, Frank R. Cockerill, Rick L. Pesano, Richard A. Festa, Natalie Luke, Mohit Mathur, Xiaofei Chen, Jim Havrilla and David Baunoch

Antibiotics 2024, 13(12), 1214; https://doi.org/10.3390/antibiotics13121214 - 14 Dec 2024

Cited by 12 | Viewed by 6892

Abstract

Background/Objectives: While new methods for measuring antimicrobial susceptibility have been associated with improved patient outcomes, they should also be validated using standard protocols for error rates and other test metrics. The objective of this study was to validate a novel susceptibility assay [...] Read more.

Background/Objectives: While new methods for measuring antimicrobial susceptibility have been associated with improved patient outcomes, they should also be validated using standard protocols for error rates and other test metrics. The objective of this study was to validate a novel susceptibility assay for complicated and recurrent urinary tract infections (UTIs): pooled antibiotic susceptibility testing (P-AST). This assay was compared to broth microdilution (BMD) and disk diffusion (DD), following Clinical and Laboratory Standards Institute (CLSI) guidelines for assessment of error rates and agreement. Methods: This study analyzed consecutive fresh clinical urine specimens submitted for UTI diagnostic testing. Upon receipt, the urine samples were subjected in parallel to standard urine culture and multiplex polymerase chain reaction (M-PCR) for microbial identification and quantification. Specimens with the same monomicrobial non-fastidious bacteria detected by both M-PCR and standard urine culture (SUC) underwent standard antibiotic susceptibility testing (AST) and P-AST antibiotic susceptibility testing. Analysis was also undertaken to assess the presence of heteroresistance for specimens with P-AST-resistant and BMD/DD consensus-susceptible results. Results: The performance measures without correction for heteroresistance showed essential agreement (EA%) of ≥90%, very major errors (VMEs) of <1.5%, and major errors (MEs) of <3.0% for P-AST, all meeting the threshold guidelines established by CLSI for AST. The categorical agreement (CA%) also met acceptable criteria (>88%), as the majority of the errors were minor (mEs) with essential agreement. The very major and major error rates for P-AST decreased to <1.0% when heteroresistance was accounted for. Conclusions: The P-AST assay methodology is validated within acceptable parameters when compared to broth microdilution and disk diffusion using CLSI criteria. Full article

(This article belongs to the Section Mechanism and Evolution of Antibiotic Resistance)

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18 pages, 4858 KB

Open AccessEditor’s ChoiceArticle

Does Antibiotic Use Contribute to Biofilm Resistance in Sink Drains? A Case Study from Four German Hospital Wards

by Nicole van Leuven, Ralf Lucassen, Anna Dicks, Patrick Braß, André Lipski and Dirk P. Bockmühl

Antibiotics 2024, 13(12), 1148; https://doi.org/10.3390/antibiotics13121148 - 1 Dec 2024

Cited by 2 | Viewed by 2175

Abstract

Backgound. As biofilms are known to harbour (multi-)resistant species, their presence in health settings must be considered critical. Although there is evidence that bacteria spread from drains to the outside, there is still a lack of research data focusing on drain biofilms [...] Read more.

Backgound. As biofilms are known to harbour (multi-)resistant species, their presence in health settings must be considered critical. Although there is evidence that bacteria spread from drains to the outside, there is still a lack of research data focusing on drain biofilms from hospitals. Methods. We sampled biofilms from various wards of Helios Hospital Krefeld (Germany), where comprehensive antibiotic consumption data were available. Biofilms were analysed by cell counting, isolation of relevant bacterial groups and genetic and phenotypical resistance parameters. Data were correlated with the prescribed antibiotics of the respective ward. Furthermore, an ex situ biofilm model was employed to investigate the influence of sub-inhibitory antibiotics on the bacterial community and the prevalence of class 1 integrons. Results. Our results show that every ward harboured medically relevant bacterial species. While no significant differences were found in cell counts, the median prevalence of the resistance marker gene intI1 correlated with the amount of prescribed antibiotics. In contrast, phenotypical resistances showed no similar tendency. In addition, melting curve analysis data and changes in intI1 prevalence show that the composition of the bacterial community shifted depending on the biofilm and antibiotic. Conclusions. To the best of our knowledge, our study is the first considering possible correlations between the consumption data of hospital wards and resistances in drain biofilms the way we did. Based on our results, we conclude that sub-inhibitory concentrations of antibiotics have no general effect on biofilms in terms of bacterial community shift and occurrence of antibiotic-resistant species. Amongst other things, the effect depends on the initial composition of the bacterial community, the antibiotic used and the intrinsic bacterial resistance, e.g., prevalence of class 1 integrons. Full article

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17 pages, 2849 KB

Open AccessEditor’s ChoiceArticle

Microbiome and Resistome Studies of the Lithuanian Baltic Sea Coast and the Curonian Lagoon Waters and Sediments

by Greta Gyraitė, Marija Kataržytė, Rafael Picazo Espinosa, Greta Kalvaitienė and Eglė Lastauskienė

Antibiotics 2024, 13(11), 1013; https://doi.org/10.3390/antibiotics13111013 - 28 Oct 2024

Cited by 3 | Viewed by 2074

Abstract

Background: the widespread use of antibiotics in human and veterinary medicine has contributed to the global challenge of antimicrobial resistance, posing significant environmental and public health risks. Objectives: this study aimed to examine the microbiome and resistome dynamics across a salinity gradient, analyzing [...] Read more.

Background: the widespread use of antibiotics in human and veterinary medicine has contributed to the global challenge of antimicrobial resistance, posing significant environmental and public health risks. Objectives: this study aimed to examine the microbiome and resistome dynamics across a salinity gradient, analyzing water and sediment samples from the Baltic Sea coast and the Curonian Lagoon between 2017 and 2023. Methods: the composition of the water and sediment bacterial community was determined by Full-Length Amplicon Metagenomics Sequencing, while ARG detection and quantification were performed using the SmartChipTM Real-Time PCR system. Results: the observed differences in bacterial community composition between the Baltic Sea coast and the Curonian Lagoon were driven by variations in salinity and chlorophyll a (chl a) concentration. The genera associated with infectious potential were observed in higher abundances in sediment than in water samples. Over 300 genes encoding antibiotic resistance (ARGs), such as aminoglycosides, beta-lactams, and multidrug resistance genes, were identified. Of particular interest were those ARGs that have previously been detected in pathogens and those currently classified as a potential future threat. Furthermore, our findings reveal a higher abundance and a distinct profile of ARGs in sediment samples from the lagoon compared to water. Conclusions: these results suggest that transitional waters such as lagoons may serve as reservoirs for ARGs, and might be influenced by anthropogenic pressures and natural processes such as salinity fluctuation and nutrient cycling. Full article

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25 pages, 1091 KB

Open AccessEditor’s ChoiceArticle

Combinations of Terminalia bellirica (Gaertn.) Roxb. and Terminalia chebula Retz. Extracts with Selected Antibiotics Against Antibiotic-Resistant Bacteria: Bioactivity and Phytochemistry

by Gagan Tiwana, Ian Edwin Cock and Matthew James Cheesman

Antibiotics 2024, 13(10), 994; https://doi.org/10.3390/antibiotics13100994 - 19 Oct 2024

Cited by 5 | Viewed by 3278

Abstract

Antimicrobial resistance (AMR) has arisen due to antibiotic overuse and misuse. Antibiotic resistance renders standard treatments less effective, making it difficult to control some infections, thereby increasing morbidity and mortality. Medicinal plants are attracting increased interest as antibiotics lose efficacy. This study evaluates [...] Read more.

Antimicrobial resistance (AMR) has arisen due to antibiotic overuse and misuse. Antibiotic resistance renders standard treatments less effective, making it difficult to control some infections, thereby increasing morbidity and mortality. Medicinal plants are attracting increased interest as antibiotics lose efficacy. This study evaluates the antibacterial activity of solvent extracts prepared using Terminalia bellirica and Terminalia chebula fruit against six bacterial pathogens using disc diffusion and broth microdilution assays. The aqueous and methanol extracts of T. bellirica and T. chebula showed substantial zones of inhibition (ZOIs) against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). The activity against those bacteria was strong, with minimum inhibitory concentrations (MIC) ranging from 94 µg/mL to 392 µg/mL. Additionally, the T. bellirica methanolic extract showed noteworthy antibacterial activity against Escherichia coli and an extended spectrum β-lactamase (ESBL) E. coli strain (MIC values of 755 µg/mL for both). The aqueous T. bellirica and T. chebula extracts also inhibited Klebsiella pneumoniae growth (MIC values of 784 µg/mL and 556 µg/mL, respectively). The corresponding methanolic extracts also inhibited ESBL K. pneumoniae growth (MIC values of 755 µg/mL and 1509 µg/mL, respectively). Eighteen additive interactions were observed when extracts were combined with reference antibiotics. Strong antagonism occurred when any of the extracts were mixed with polymyxin B. Liquid chromatography-mass spectroscopy (LC-MS) analysis of the extracts revealed several interesting flavonoids and tannins, including 6-galloylglucose, 1,2,6-trigalloyl-β-D-glucopyranose, 6-O-[(2E)-3-phenyl-2-propenoyl]-1-O-(3,4,5-trihydroxybenzoyl)-β-D-glucopyranose, propyl gallate, methyl gallate, sanguiin H4, hamamelitannin, pyrogallol, gallic acid, ellagic acid, chebulic acid, and chebuloside II. All extracts were nontoxic in brine shrimp assays. This lack of toxicity, combined with their antibacterial activities, suggests that these plant species may be promising sources of antibacterial compound(s) that warrant further study. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Products and Plants Extracts)

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21 pages, 1022 KB

Open AccessEditor’s ChoiceArticle

Genomic Analyses of Methicillin-Resistant Staphylococcus pseudintermedius from Companion Animals Reveal Changing Clonal Populations, Multidrug Resistance, and Virulence

by Mattias Myrenås, Karl Pedersen and Ulrika Windahl

Antibiotics 2024, 13(10), 962; https://doi.org/10.3390/antibiotics13100962 - 12 Oct 2024

Cited by 5 | Viewed by 2488

Abstract

Background/Objectives: Staphylococcus pseudintermedius is part of the normal microbiota in dogs. Since 2006, an increase in multidrug-resistant clones of methicillin-resistant S. pseudintermedius has been reported, as well as zoonotic transmission. Longitudinal investigations into clonal population structures, antibiotic resistance patterns, and the presence of [...] Read more.

Background/Objectives: Staphylococcus pseudintermedius is part of the normal microbiota in dogs. Since 2006, an increase in multidrug-resistant clones of methicillin-resistant S. pseudintermedius has been reported, as well as zoonotic transmission. Longitudinal investigations into clonal population structures, antibiotic resistance patterns, and the presence of resistance and virulence genes are important tools for gaining knowledge of the mechanisms behind the emergence of such clones. Methods: We investigated 87% of all non-repetitive MRSP isolates from dogs and cats in Sweden over a ten-year period (n = 356). All isolates were subjected to staphylococcal chromosomal cassette mec identification, whole-genome sequencing, multi-locus sequence typing, and analyses of genomic relatedness, as well as investigation of phenotypical resistance patterns and the presence of antibiotic resistance genes and virulence genes. Results: A considerable increase over time in the number of clonal lineages present was observed, indicating genomic diversification, and four clones became dominant: ST71, ST258, ST265, and ST551. In total, 96% of the isolates were multidrug-resistant. Statistically significant differences in resistance to several antibiotic classes between the four dominant clones were present. All isolates carried several virulence genes encoding factors associated with attachment, colonization, toxin synthesis, quorum sensing, antibiotic resistance, and immune evasion. Full article

(This article belongs to the Special Issue Antibiotic Resistance in Companion and Food-Producing Animals, 2nd Edition)

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32 pages, 6288 KB

Open AccessEditor’s ChoiceReview

A Decade of Antimicrobial Resistance in Human and Animal Campylobacter spp. Isolates

by Rita Barata, Maria José Saavedra and Gonçalo Almeida

Antibiotics 2024, 13(9), 904; https://doi.org/10.3390/antibiotics13090904 - 21 Sep 2024

Cited by 11 | Viewed by 6114

Abstract

Objectives: Campylobacter spp. remain a leading cause of bacterial gastroenteritis worldwide, with resistance to antibiotics posing significant challenges to treatment and public health. This study examines profiles in antimicrobial resistance (AMR) for Campylobacter isolates from human and animal sources over the past [...] Read more.

Objectives: Campylobacter spp. remain a leading cause of bacterial gastroenteritis worldwide, with resistance to antibiotics posing significant challenges to treatment and public health. This study examines profiles in antimicrobial resistance (AMR) for Campylobacter isolates from human and animal sources over the past decade. Methods: We conducted a comprehensive review of resistance data from studies spanning ten years, analyzing profiles in resistance to key antibiotics, ciprofloxacin (CIP), tetracycline (TET), erythromycin (ERY), chloramphenicol (CHL), and gentamicin (GEN). Data were collated from various regions to assess global and regional patterns of resistance. Results: The analysis reveals a concerning trend of increasing resistance patterns, particularly to CIP and TET, across multiple regions. While resistance to CHL and GEN remains relatively low, the high prevalence of CIP resistance has significantly compromised treatment options for campylobacteriosis. Discrepancies in resistance patterns were observed between human and animal isolates, with variations across different continents and countries. Notably, resistance to ERY and CHL showed regional variability, reflecting potential differences in antimicrobial usage and management practices. Conclusions: The findings underscore the ongoing challenge of AMR in Campylobacter, highlighting the need for continued surveillance and research. The rising resistance prevalence, coupled with discrepancies in resistance patterns between human and animal isolates, emphasize the importance of a One Health approach to address AMR. Enhanced monitoring, novel treatment strategies, and global cooperation are crucial for mitigating the impact of resistance and ensuring the effective management of Campylobacter-related infections. Full article

(This article belongs to the Special Issue Challenges and Emerging Strategies to Tackle the Global Burden of Antimicrobial Resistance)

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16 pages, 5378 KB

Open AccessEditor’s ChoiceArticle

Alkyl Pyridinol Compounds Exhibit Antimicrobial Effects against Gram-Positive Bacteria

by Juan Canchola, Gracious Yoofi Boafo Donkor, Patrick Ofori Tawiah, Ayoola Fasawe, Emmanuel Ayim, Martin F. Engelke and Jan-Ulrik Dahl

Antibiotics 2024, 13(9), 897; https://doi.org/10.3390/antibiotics13090897 - 20 Sep 2024

Cited by 1 | Viewed by 2398

Abstract

Background/Objectives. The rise of antibiotic-resistant pathogens represents a significant global challenge in infectious disease control, which is amplified by the decline in the discovery of novel antibiotics. Staphylococcus aureus continues to be a highly significant pathogen, causing infections in multiple organs and tissues [...] Read more.

Background/Objectives. The rise of antibiotic-resistant pathogens represents a significant global challenge in infectious disease control, which is amplified by the decline in the discovery of novel antibiotics. Staphylococcus aureus continues to be a highly significant pathogen, causing infections in multiple organs and tissues in both healthcare institutions and community settings. The bacterium has become increasingly resistant to all available antibiotics. Consequently, there is an urgent need for novel small molecules that inhibit the growth or impair the survival of bacterial pathogens. Given their large structural and chemical diversity, as well as often unique mechanisms of action, natural products represent an excellent avenue for the discovery and development of novel antimicrobial treatments. Anaephene A and B are two such naturally occurring compounds with significant antimicrobial activity against Gram-positive bacteria. Here, we report the rapid syntheses and biological characterization of five novel anaephene derivatives, which display low cytotoxicity against mammalian cells but potent antibacterial activity against various S. aureus strains, including methicillin-resistant S. aureus (MRSA) and the multi-drug-resistant community-acquired strain USA300LAC. Methods. A Sonogashira cross-coupling reaction served as the key step for the synthesis of the alkyl pyridinol products. Results/Conclusions. Using the compound JC-01-074, which displays bactericidal activity already at low concentrations (MIC: 16 μg/mL), we provide evidence that alkyl pyridinols target actively growing and biofilm-forming cells and show that these compounds cause disruption and deformation of the staphylococcal membrane, indicating a membrane-associated mechanism of action. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Drug Discovery, 2nd Edition)

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21 pages, 5445 KB

Open AccessEditor’s ChoiceArticle

Characterization of Two Novel Endolysins from Bacteriophage PEF1 and Evaluation of Their Combined Effects on the Control of Enterococcus faecalis Planktonic and Biofilm Cells

by Chen Wang, Junxin Zhao, Yunzhi Lin, Su Zar Chi Lwin, Mohamed El-Telbany, Yoshimitsu Masuda, Ken-ichi Honjoh and Takahisa Miyamoto

Antibiotics 2024, 13(9), 884; https://doi.org/10.3390/antibiotics13090884 - 13 Sep 2024

Cited by 3 | Viewed by 2662

Abstract

Endolysin, a bacteriophage-derived lytic enzyme, has emerged as a promising alternative antimicrobial agent against rising multidrug-resistant bacterial infections. Two novel endolysins LysPEF1-1 and LysPEF1-2 derived from Enterococcus phage PEF1 were cloned and overexpressed in Escherichia coli to test their antimicrobial efficacy against multidrug-resistant [...] Read more.

Endolysin, a bacteriophage-derived lytic enzyme, has emerged as a promising alternative antimicrobial agent against rising multidrug-resistant bacterial infections. Two novel endolysins LysPEF1-1 and LysPEF1-2 derived from Enterococcus phage PEF1 were cloned and overexpressed in Escherichia coli to test their antimicrobial efficacy against multidrug-resistant E. faecalis strains and their biofilms. LysPEF1-1 comprises an enzymatically active domain and a cell-wall-binding domain originating from the NLPC-P60 and SH3 superfamilies, while LysPEF1-2 contains a putative peptidoglycan recognition domain that belongs to the PGRP superfamily. LysPEF1-1 was active against 89.86% (62/69) of Enterococcus spp. tested, displaying a wider antibacterial spectrum than phage PEF1. Moreover, two endolysins demonstrated lytic activity against additional gram-positive and gram-negative species pretreated with chloroform. LysPEF1-1 showed higher activity against multidrug-resistant E. faecalis strain E5 than LysPEF1-2. The combination of two endolysins effectively reduced planktonic cells of E5 in broth and was more efficient at inhibiting biofilm formation and removing biofilm cells of E. faecalis JCM 7783^T than used individually. Especially at 4 °C, they reduced viable biofilm cells by 4.5 log after 2 h of treatment on glass slide surfaces. The results suggest that two novel endolysins could be alternative antimicrobial agents for controlling E. faecalis infections. Full article

(This article belongs to the Special Issue Phage Applications from Diagnostics to Treatment of Bacterial Infections in a One Health World)

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21 pages, 11964 KB

Open AccessEditor’s ChoiceArticle

Novel Antimicrobial Agents Based on Zinc-Doped Hydroxyapatite Loaded with Tetracycline

by Simona Liliana Iconaru, Daniela Predoi, Carmen Steluta Ciobanu, Catalin Constantin Negrila, Roxana Trusca, Steinar Raaen, Krzysztof Rokosz, Liliana Ghegoiu, Monica Luminita Badea and Carmen Cimpeanu

Antibiotics 2024, 13(9), 803; https://doi.org/10.3390/antibiotics13090803 - 25 Aug 2024

Cited by 1 | Viewed by 2243

Abstract

In this paper, we present for the first time the development of zinc-doped hydroxyapatite enriched with tetracycline (ZnHApTe) powders and provide a comprehensive evaluation of their physico-chemical and biological properties. Various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron [...] Read more.

In this paper, we present for the first time the development of zinc-doped hydroxyapatite enriched with tetracycline (ZnHApTe) powders and provide a comprehensive evaluation of their physico-chemical and biological properties. Various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used for the sample’s complex evaluation. Moreover, the biocompatibility of zinc-doped hydroxyapatite (ZnHAp) and ZnHApTe nanoparticles was evaluated with the aid of human fetal osteoblastic cells (hFOB 1.19 cell line). The results of the biological assays suggested that these nanoparticles hold great promise as potential candidates for the future development of novel biocompatible and antimicrobial agents for biomedical applications. The antimicrobial properties of the ZnHAp and ZnHApTe nanoparticles were assessed using the standard reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231. The results of the in vitro antimicrobial assay demonstrated that both tested materials exhibited good antimicrobial activity. Additionally, these data also indicated that the antimicrobial effects of the ZnHAp nanoparticles were intensified by the presence of tetracycline (Te). Furthermore, the results also suggested that the antimicrobial activity of the samples increased with the incubation time. Full article

(This article belongs to the Special Issue Nanomaterials as Antimicrobial Agents for Biomedical Applications)

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23 pages, 4568 KB

Open AccessEditor’s ChoiceArticle

Bacteriophage Therapy on an In Vitro Wound Model and Synergistic Effects in Combination with Beta-Lactam Antibiotics

by Guillermo Santamaría-Corral, John Jairo Aguilera-Correa, Jaime Esteban and Meritxell García-Quintanilla

Antibiotics 2024, 13(9), 800; https://doi.org/10.3390/antibiotics13090800 - 24 Aug 2024

Cited by 1 | Viewed by 2251

Abstract

One of the primary opportunistic pathogens that can cause a wide range of diseases is Pseudomonas aeruginosa. This microorganism can become resistant to practically every antibacterial currently in use, including beta-lactam antibiotics. Its ability to proliferate as biofilm has been linked to, [...] Read more.

One of the primary opportunistic pathogens that can cause a wide range of diseases is Pseudomonas aeruginosa. This microorganism can become resistant to practically every antibacterial currently in use, including beta-lactam antibiotics. Its ability to proliferate as biofilm has been linked to, among other things, the failure of antimicrobial therapies. Due to a variety of virulence factors and host immune system modifications, P. aeruginosa is one of the most significant and common bacteria that colonize wounds and burns. A novel therapeutic option for treating these multidrug-resistant (MDR) bacterial infections is the combination of antibiotics and bacteriophages. This approach has been linked to improved biofilm penetration, a decreased selection of antibiotic and bacteriophage resistance, and an enhanced antibacterial impact. Combining the F1Pa bacteriophage and beta-lactam antibiotics reduced the viability of the mature biofilm of MDR P. aeruginosa strains and suppressed bacterial growth in vitro. F1Pa critically reduced the amount of biofilm that MDR P. aeruginosa clinical strains formed in the in vitro wound model. These findings highlight the bacteriophage F1Pa’s therapeutic potential as a prophylactic topical treatment against MDR pseudomonal infections in wounds and burns. Full article

(This article belongs to the Special Issue Bacteriophage Therapy a Renaissance Weapon Recent Developments and Application, 2nd Edition)

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14 pages, 3106 KB

Open AccessEditor’s ChoiceArticle

Development of a Galleria mellonella Infection Model to Evaluate the Efficacy of Antibiotic-Loaded Polymethyl Methacrylate (PMMA) Bone Cement

by You Zhao, Gopala Krishna Mannala, Raphaëlle Youf, Markus Rupp, Volker Alt and Martijn Riool

Antibiotics 2024, 13(8), 692; https://doi.org/10.3390/antibiotics13080692 - 25 Jul 2024

Cited by 5 | Viewed by 2845

Abstract

Prosthetic joint infections (PJIs) can have disastrous consequences for patient health, including removal of the device, and placement of cemented implants is often required during surgery to eradicate PJIs. In translational research, in vivo models are widely used to assess the biocompatibility and [...] Read more.

Prosthetic joint infections (PJIs) can have disastrous consequences for patient health, including removal of the device, and placement of cemented implants is often required during surgery to eradicate PJIs. In translational research, in vivo models are widely used to assess the biocompatibility and antimicrobial efficacy of antimicrobial coatings and compounds. Here, we aim to utilize Galleria mellonella implant infection models to assess the antimicrobial activity of antibiotic-loaded bone cement (ALBC) implants. Therefore, we used commercially available bone cement loaded with either gentamicin alone (PALACOS R+G) or with a combination of gentamicin and vancomycin (COPAL G+V), compared to bone cement without antibiotics (PALACOS R). Firstly, the in vitro antimicrobial activity of ALBC was determined against Staphylococcus aureus. Next, the efficacy of ALBC implants was analyzed in both the G. mellonella hematogenous and early-stage biofilm implant infection model, by monitoring the survival of larvae over time. After 24 h, the number of bacteria on the implant surface and in the tissue was determined. Larvae receiving dual-loaded COPAL G+V implants showed higher survival rates compared to implants loaded with only gentamicin (PALACOS R+G) and the control implants without antibiotics (PALACOS R). In conclusion, G. mellonella larvae infection models with antibiotic-loaded bone cements are an excellent option to study (novel) antimicrobial approaches. Full article

(This article belongs to the Special Issue Local Antibiotics: Antibiotic Loaded Bone Cement and Drug Containing Medical Devices in Orthopaedic Surgery)

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18 pages, 14184 KB

Open AccessEditor’s ChoiceArticle

Isolation and Characterization of Novel Bacteriophages to Target Carbapenem-Resistant Acinetobacter baumannii

by Yoon-Jung Choi, Shukho Kim, Minsang Shin and Jungmin Kim

Antibiotics 2024, 13(7), 610; https://doi.org/10.3390/antibiotics13070610 - 29 Jun 2024

Cited by 15 | Viewed by 4485

Abstract

The spread of multidrug-resistant Acinetobacter baumannii in hospitals and nursing homes poses serious healthcare challenges. Therefore, we aimed to isolate and characterize lytic bacteriophages targeting carbapenem-resistant Acinetobacter baumannii (CRAB). Of the 21 isolated A. baumannii phages, 11 exhibited potent lytic activities against clinical [...] Read more.

The spread of multidrug-resistant Acinetobacter baumannii in hospitals and nursing homes poses serious healthcare challenges. Therefore, we aimed to isolate and characterize lytic bacteriophages targeting carbapenem-resistant Acinetobacter baumannii (CRAB). Of the 21 isolated A. baumannii phages, 11 exhibited potent lytic activities against clinical isolates of CRAB. Based on host spectrum and RAPD-PCR results, 11 phages were categorized into four groups. Three phages (vB_AbaP_W8, vB_AbaSi_W9, and vB_AbaSt_W16) were further characterized owing to their antibacterial efficacy, morphology, and whole-genome sequence and were found to lyse 37.93%, 89.66%, and 37.93%, respectively, of the 29 tested CRAB isolates. The lytic spectrum of phages varied depending on the multilocus sequence type (MLST) of the CRAB isolates. The three phages contained linear double-stranded DNA genomes, with sizes of 41,326–166,741 bp and GC contents of 34.4–35.6%. Genome-wide phylogenetic analysis and single gene-based tree construction revealed no correlation among the three phages. Moreover, no genes were associated with lysogeny, antibiotic resistance, or bacterial toxins. Therefore, the three novel phages represent potential candidates for phage therapy against CRAB infections. Full article

(This article belongs to the Special Issue Bacteriophages and Other Alternative Antimicrobials to Combat Multidrug Resistance)

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12 pages, 1466 KB

Open AccessEditor’s ChoiceArticle

Implementation of a Multifaceted Program to Improve the Rational Use of Antibiotics in Children under 3 Years of Age in Primary Care

by Santiago Alfayate-Miguélez, Gema Martín-Ayala, Casimiro Jiménez-Guillén, Manuel Alcaraz-Quiñonero, Rafael Herrero Delicado and José Arnau-Sánchez

Antibiotics 2024, 13(7), 572; https://doi.org/10.3390/antibiotics13070572 - 21 Jun 2024

Viewed by 2426

Abstract

A multifaceted, participatory, open program based on a qualitative and quantitative approach was developed in the Region of Murcia (Spain) aimed to reduce antibiotic use in children under 3 years of age diagnosed with upper respiratory tract infections (acute otitis media, pharyngitis, and [...] Read more.

A multifaceted, participatory, open program based on a qualitative and quantitative approach was developed in the Region of Murcia (Spain) aimed to reduce antibiotic use in children under 3 years of age diagnosed with upper respiratory tract infections (acute otitis media, pharyngitis, and common cold). Antibiotic consumption was measured using the defined daily dose per 1000 inhabitants per day (DHD). Pre-intervention data showed a prevalence of antibiotic prescriptions in the primary care setting of 45.7% and a DHD of 19.05. In 2019, after the first year of implementation of the program, antibiotic consumption was 10.25 DHD with an overall decrease of 48% as compared with 2015. Although antibiotic consumption decreased in all health areas, there was a large variability in the magnitude of decreases across health areas (e.g., 12.97 vs. 4.77 DHD). The intervention program was effective in reducing the use of antibiotics in children under 3 years of age with common upper respiratory diseases, but reductions in antibiotic consumption were not consistent among all health areas involved. Full article

(This article belongs to the Special Issue Inappropriate Use of Antibiotics in Pediatrics)

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12 pages, 1553 KB

Open AccessEditor’s ChoiceArticle

Demographic Characteristics and Economic Burden of Clostridioides difficile Infection in Korea: A Nationwide Population-Based Study after Propensity Score Matching

by Jae Myung Cha, Jin Young Yoon, Min Seob Kwak, Moonhyung Lee and Young-Seok Cho

Antibiotics 2024, 13(6), 542; https://doi.org/10.3390/antibiotics13060542 - 10 Jun 2024

Cited by 4 | Viewed by 2043

Abstract

Clostridioides difficile infection (CDI) poses a considerable threat to global public health. However, there have been insufficient propensity score-matched data on its demographic characteristics and economic burden. Using nationwide claims data, we assessed longitudinal changes in the demographic characteristics and economic burden of [...] Read more.

Clostridioides difficile infection (CDI) poses a considerable threat to global public health. However, there have been insufficient propensity score-matched data on its demographic characteristics and economic burden. Using nationwide claims data, we assessed longitudinal changes in the demographic characteristics and economic burden of CDI between 2011 and 2019 after propensity score matching. We performed a regression analysis to compare the differences in the length of hospital stay and medical costs between patients with CDI and controls (gastroenteritis and colitis). The CDI hospitalization rate increased 2.9-fold between 2011 and 2019. The CDI group had higher comorbidity index scores and was more frequently diagnosed at tertiary hospitals and in the Seoul region than the control group (all p < 0.001). The annual incidence rate of CDI/10,000 persons significantly increased in both sexes and all age groups. The length of hospital stay and medical costs were 3.3-fold and 5.0-fold greater, respectively, in the CDI than in the control group (both p < 0.001). Although the length of hospital stay decreased, total medical costs increased in all age groups and both sexes between 2011 and 2019 (all p < 0.001). When compared with the control group, the CDI-attributable length of hospital stay and medical cost were greater by 15.3 days and KRW 3413 (×10³), respectively, after matching. In conclusion, CDI incidence, particularly among the elderly population with comorbidities, has been increasing. In addition, the length of hospital stay and total medical costs of the CDI group were greater than those of the control group. Full article

(This article belongs to the Special Issue Clostridioides difficile Infection, 3rd Edition)

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17 pages, 2142 KB

Open AccessEditor’s ChoiceArticle

Impact of Soil Fertilization with Pig Slurry on Antibiotic Residues and Resistance Genes: A Longitudinal Study

by Luisa Massaccesi, Elisa Albini, Francesca Romana Massacci, Danilo Giusepponi, Fabiola Paoletti, Stefano Sdogati, Francesco Morena, Alberto Agnelli, Angelo Leccese, Chiara Francesca Magistrali and Roberta Galarini

Antibiotics 2024, 13(6), 486; https://doi.org/10.3390/antibiotics13060486 - 24 May 2024

Cited by 4 | Viewed by 2645

Abstract

The impact of soil fertilization with animal manure on the spread and persistence of antibiotic resistance in the environment is far from being fully understood. To add knowledge about persistence and correlations between antibiotic residues and antibiotic resistance genes (ARGs) in fertilized soil, [...] Read more.

The impact of soil fertilization with animal manure on the spread and persistence of antibiotic resistance in the environment is far from being fully understood. To add knowledge about persistence and correlations between antibiotic residues and antibiotic resistance genes (ARGs) in fertilized soil, a longitudinal soil mesocosm study was conducted. Soil samples were collected from the mesocosms immediately before spreading and then afterward at fifteen time points during a 320-day observation period. Eight ARGs (ermB, sul1, tetA, tetG, tetM, cfr, fexA, and optrA) and the class 1 integron-integrase gene, intI1, were determined in both pig slurry and soil, as well as residues of 36 antibiotics. Soil chemical and biochemical parameters were also measured. Twelve antibiotics were detected in the slurry in the range of 3 µg kg⁻¹–3605 µg kg⁻¹, with doxycycline, lincomycin, and tiamulin being the most abundant, whereas ermB, sul1, and tetM were the predominant ARGs. Before spreading, neither antibiotic residues nor ARGs were detectable in the soil; afterwards, their concentrations mirrored those in the slurry, with a gradual decline over the duration of the experiment. After about three months, the effect of the amendment was almost over, and no further evolution was observed. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Monitoring in Food-Producing Animals)

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30 pages, 5934 KB

Open AccessEditor’s ChoiceArticle

The MraY Inhibitor Muraymycin D2 and Its Derivatives Induce Enlarged Cells in Obligate Intracellular Chlamydia and Wolbachia and Break the Persistence Phenotype in Chlamydia

by Iris Löckener, Lara Vanessa Behrmann, Jula Reuter, Andrea Schiefer, Anna Klöckner, Sebastian Krannich, Christian Otten, Katja Mölleken, Satoshi Ichikawa, Achim Hoerauf, Tanja Schneider, Kenneth M. Pfarr and Beate Henrichfreise

Antibiotics 2024, 13(5), 421; https://doi.org/10.3390/antibiotics13050421 - 4 May 2024

Cited by 2 | Viewed by 2973

Abstract

Chlamydial infections and diseases caused by filarial nematodes are global health concerns. However, treatment presents challenges due to treatment failures potentially caused by persisting Chlamydia and long regimens against filarial infections accompanied by low compliance. A new treatment strategy could be the targeting [...] Read more.

Chlamydial infections and diseases caused by filarial nematodes are global health concerns. However, treatment presents challenges due to treatment failures potentially caused by persisting Chlamydia and long regimens against filarial infections accompanied by low compliance. A new treatment strategy could be the targeting of the reduced peptidoglycan structures involved in cell division in the obligate intracellular bacteria Chlamydia and Wolbachia, the latter being obligate endosymbionts supporting filarial development, growth, and survival. Here, cell culture experiments with C. trachomatis and Wolbachia showed that the nucleoside antibiotics muraymycin and carbacaprazamycin interfere with bacterial cell division and induce enlarged, aberrant cells resembling the penicillin-induced persistence phenotype in Chlamydia. Enzymatic inhibition experiments with purified C. pneumoniae MraY revealed that muraymycin derivatives abolish the synthesis of the peptidoglycan precursor lipid I. Comparative in silico analyses of chlamydial and wolbachial MraY with the corresponding well-characterized enzyme in Aquifex aeolicus revealed a high degree of conservation, providing evidence for a similar mode of inhibition. Muraymycin D2 treatment eradicated persisting non-dividing C. trachomatis cells from an established penicillin-induced persistent infection. This finding indicates that nucleoside antibiotics may have additional properties that can break bacterial persistence. Full article

(This article belongs to the Section Novel Antimicrobial Agents)

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16 pages, 3192 KB

Open AccessEditor’s ChoiceArticle

Bacitracin Methylene Disalicylate (BMD) Treatment Affects Spleen Proteome in Broiler Chicks Infected with Salmonella enteritidis

by Adedeji Adetunji, Theresa Casey, Uma K. Aryal, Tunde Ogundare, Jackeline Franco and Yewande Fasina

Antibiotics 2024, 13(5), 414; https://doi.org/10.3390/antibiotics13050414 - 1 May 2024

Cited by 1 | Viewed by 3701

Abstract

Bacitracin Methylene Disalicylate (BMD), as a feed additive to poultry diets, enhances digestion, prevents Salmonella enteritidis (SE) colonization, and treats current infections. The objective of this study was to utilize a quantitative proteomic approach to determine the effect of BMD feed additive on [...] Read more.

Bacitracin Methylene Disalicylate (BMD), as a feed additive to poultry diets, enhances digestion, prevents Salmonella enteritidis (SE) colonization, and treats current infections. The objective of this study was to utilize a quantitative proteomic approach to determine the effect of BMD feed additive on broiler chickens challenged with SE in the spleen proteome. At 1 d of age, chicks were randomly allocated into four groups: control with and without SE challenge (CON, n = 60; CON-SE, n = 60), BMD with and without SE challenge (BMD, n = 60; BMD-SE, n = 60). Birds in the CON-SE and BMD-SE treatment were administered SE inoculum by oral gavage. On day three and day seven post-gavage, the spleen was collected aseptically from birds in each treatment group (CON, n = 4/day; CON-SE, n = 4/day; BMD, n = 4/day; BMD-SE, n = 4/day). Proteomic analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed an increased abundance of 115 proteins and decreased of 77 due to the BMD. Proteins that decreased in abundance were enriched for fibrinogen complex and extracellular space, whereas proteins that increased in abundance were enriched for proteasome-mediated ubiquitin-dependent protein catabolic process and mitochondrion. Analysis of the interaction between BMD and the Salmonella challenge found 230 differentially abundant proteins including proteins associated with RNA binding, spliceosome, protein transport, and cell adhesion among the upregulated proteins, and those associated with protein folding, carbon metabolism, biosynthesis of nucleotide sugars, response to oxidative stress, positive regulation of NIK/NF-kappaB signaling, and inflammatory response among the downregulated proteins. The impact of BMD treatment on spleen proteome indicates an anti-apoptotic effect. BMD also modified the response of the spleen to the SE challenge with a marked decrease in proteins that prompt cytokine synthesis and an increase in proteins involved in the selective removal of unfolded proteins. Full article

(This article belongs to the Topic Animal Diseases in Agricultural Production Systems: Their Veterinary, Zoonotic, and One Health Importance, 2nd Edition)

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19 pages, 4683 KB

Open AccessEditor’s ChoiceArticle

Efficacy of Tamoxifen Metabolites in Combination with Colistin and Tigecycline in Experimental Murine Models of Escherichia coli and Acinetobacter baumannii

by Soraya Herrera-Espejo, Andrea Vila-Domínguez, Tania Cebrero-Cangueiro, Younes Smani, Jerónimo Pachón, Manuel E. Jiménez-Mejías and María E. Pachón-Ibáñez

Antibiotics 2024, 13(5), 386; https://doi.org/10.3390/antibiotics13050386 - 24 Apr 2024

Cited by 4 | Viewed by 2429

Abstract

This study aimed to evaluate the potential of tamoxifen and N-desmethyltamoxifen metabolites as therapeutic agents against multidrug-resistant Escherichia coli and Acinetobacter baumannii, using a repurposing approach to shorten the time required to obtain a new effective treatment against multidrug-resistant bacterial infections. Characterisation and [...] Read more.

This study aimed to evaluate the potential of tamoxifen and N-desmethyltamoxifen metabolites as therapeutic agents against multidrug-resistant Escherichia coli and Acinetobacter baumannii, using a repurposing approach to shorten the time required to obtain a new effective treatment against multidrug-resistant bacterial infections. Characterisation and virulence studies were conducted on E. coli (colistin-susceptible C1-7-LE and colistin-resistant MCR-1+) and A. baumannii (tigecycline-susceptible Ab#9 and tigecycline-resistant Ab#186) strains. The efficacy of the metabolite mix (33.3% each) and N-desmethyltamoxifen in combination with colistimethate sodium (CMS) or tigecycline was evaluated in experimental models in mice. In the pneumonia model, N-desmethyltamoxifen exhibited significant efficacy against Ab#9 and both E. coli strains, especially E. coli MCR-1+ (−2.86 log₁₀ CFU/g lungs, −5.88 log₁₀ CFU/mL blood, and −50% mortality), and against the Ab#186 strain when combined with CMS (−2.27 log₁₀ CFU/g lungs, −2.73 log₁₀ CFU/mL blood, and −40% mortality) or tigecycline (−3.27 log₁₀ CFU/g lungs, −4.95 log₁₀ CFU/mL blood, and −50% mortality). Moreover, the metabolite mix in combination with both antibiotics decreased the bacterial concentrations in the lungs and blood for both A. baumannii strains. In the sepsis model, the significant efficacy of the metabolite mix was restricted to the colistin-susceptible E. coli C1-7-LE strain (−3.32 log₁₀ CFU/g lung, −6.06 log₁₀ CFU/mL blood, and −79% mortality). N-desmethyltamoxifen could be a new therapeutic option in combination with CMS or tigecycline for combating multidrug-resistant GNB, specifically A. baumannii. Full article

(This article belongs to the Special Issue Advancing the Discovery and Development of New Antibiotics through Drug Repurposing)

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10 pages, 228 KB

Open AccessEditor’s ChoiceArticle

Evaluating the Clinical Relevance of Routine Sonication for Periprosthetic Hip or Knee Joint Infection Diagnosis

by Anas Zouitni, Jakob van Oldenrijk, P. Koen Bos, Peter D. Croughs, Erlangga Yusuf and Ewout S. Veltman

Antibiotics 2024, 13(4), 366; https://doi.org/10.3390/antibiotics13040366 - 17 Apr 2024

Cited by 4 | Viewed by 3117

Abstract

Periprosthetic joint infection (PJI) is a serious complication after joint arthroplasty. PJI screening and conventional cultures may be inconclusive. Sonication fluid culturing stands out as a valuable adjunct technique for PJI diagnosis. This study aims to determine the clinical relevance of routine sonication [...] Read more.

Periprosthetic joint infection (PJI) is a serious complication after joint arthroplasty. PJI screening and conventional cultures may be inconclusive. Sonication fluid culturing stands out as a valuable adjunct technique for PJI diagnosis. This study aims to determine the clinical relevance of routine sonication for all (a)septic revisions. All patients who underwent (partial) hip or knee revision arthroplasty between 2012 and 2021 were retrospectively reviewed. We formed three groups based on the European Bone and Joint Society PJI criteria: infection confirmed, likely, and unlikely. We analyzed clinical, laboratory, and radiological screening. Sensitivity and specificity were calculated for synovial fluid (preoperative), tissue, and sonication fluid cultures. We determined the clinical relevance of sonication as the percentage of patients for whom sonication confirmed PJI; 429 patients who underwent (partial) revision of hip or knee arthroplasty were included. Sensitivity and specificity were 69% and 99% for synovial fluid cultures, 76% and 92% for tissue cultures, and 80% and 89% for sonication fluid cultures, respectively. Sonication fluid cultures improved tissue culture sensitivity and specificity to 83% and 99%, respectively. In 11% of PJIs, sonication fluid cultures were decisive for diagnosis. This is applicable to acute and chronic infections. Sonication fluid cultures enhanced the sensitivity and specificity of PJI diagnostics. In 11% of PJI cases, causative pathogens were confirmed by sonication fluid culture results. Sonication fluid culture should be performed in all revision arthroplasties. Full article

(This article belongs to the Special Issue Antibiotic Therapy in Implant Related Orthopedic Infections)

22 pages, 6012 KB

Open AccessEditor’s ChoiceArticle

Repurposing Farnesol for Combating Drug-Resistant and Persistent Single and Polymicrobial Biofilms

by Li Tan, Rong Ma, Tony Reeves, Adam J. Katz and Nicole Levi

Antibiotics 2024, 13(4), 350; https://doi.org/10.3390/antibiotics13040350 - 11 Apr 2024

Cited by 9 | Viewed by 2758

Abstract

Biofilm-associated infections caused by drug-resistant and persistent bacteria remain a significant clinical challenge. Here we report that farnesol, commercially available as a cosmetic and flavoring agent, shows significant anti-biofilm properties when dissolved in ethanol using a proprietary formulation emulsion technique. Farnesol in the [...] Read more.

Biofilm-associated infections caused by drug-resistant and persistent bacteria remain a significant clinical challenge. Here we report that farnesol, commercially available as a cosmetic and flavoring agent, shows significant anti-biofilm properties when dissolved in ethanol using a proprietary formulation emulsion technique. Farnesol in the new formulation inhibits biofilm formation and disrupts established biofilms for Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa, including their polymicrobial biofilms, and, moreover, kills S. aureus persister cells that have developed tolerance to antibiotics. No resistance to farnesol was observed for S. aureus after twenty continuous passages. Farnesol combats biofilms by direct killing, while also facilitating biofilm detachment. Furthermore, farnesol was safe and effective for preventing and treating biofilm-associated infections of both types of bacteria in an ex vivo burned human skin model. These data suggest that farnesol in the new formulation is an effective broad-spectrum anti-biofilm agent with promising clinical potential. Due to its established safety, low-cost, versatility, and excellent efficacy—including ability to reduce persistent and resistant microbial populations—farnesol in the proprietary formulation represents a compelling transformative, translational, and commercial platform for addressing many unsolved clinical challenges. Full article

(This article belongs to the Special Issue Novel and Traditional Methods to Fight Antibiotic Resistant Bacteria and Biofilm Infections)

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17 pages, 2227 KB

Open AccessEditor’s ChoiceArticle

Insights into the Evolution of IncR Plasmids Found in the Southern European Clone of the Monophasic Variant of Salmonella enterica Serovar Typhimurium

by Xenia Vázquez, Javier Fernández, Jürgen J. Heinisch, Rosaura Rodicio and M. Rosario Rodicio

Antibiotics 2024, 13(4), 314; https://doi.org/10.3390/antibiotics13040314 - 29 Mar 2024

Cited by 1 | Viewed by 2551

Abstract

Salmonella enterica subspecies enterica serovar 4,[5],12:i:- is a monophasic variant of S. Typhimurium which has emerged as a world-wide distributed pathogen in the last decades. Several clones have been identified within this variant, the European clone, the Spanish clone, the Southern European [...] Read more.

Salmonella enterica subspecies enterica serovar 4,[5],12:i:- is a monophasic variant of S. Typhimurium which has emerged as a world-wide distributed pathogen in the last decades. Several clones have been identified within this variant, the European clone, the Spanish clone, the Southern European clone and the U.S./American clone. The present study focused on isolates of the Southern European clone that were obtained from clinical samples at Spanish hospitals. The selected isolates were multidrug resistant, with most resistance genes residing on IncR plasmids that also carried virulence genes. These plasmids had a mosaic structure, comprising a highly reduced IncR backbone, which has acquired a large amount of exogenous DNA mostly derived from pSLT and IncI1-I(alfa) plasmids. Although composed of approximately the same elements, the investigated plasmids displayed a high diversity, consistent with active evolution driven by a wealth of mobile genetic elements. They comprise multiple intact or truncated insertion sequences, transposons, pseudo-compound transposons and integrons. Particularly relevant was the role of IS26 (with six to nine copies per plasmid) in generating insertions, deletions and inversions, with many of the rearrangements uncovered by tracking the patterns of eight bp target site duplications. Most of the resistance genes detected in the analyzed isolates have been previously associated with the Southern European clone. However, erm(B), lnu(G) and bla_TEM-1B are novel, with the last two carried by a second resistance plasmid found in one of the IncR-positive isolates. Thus, evolution of resistance in the Southern European clone is not only mediated by diversification of the IncR plasmids, but also through acquisition of additional plasmids. All isolates investigated in the present study have the large deletion affecting the fljBA region previously found to justify the monophasic phenotype in the Southern European and U.S./American clones. An SNP-based phylogenetic analysis revealed the close relationship amongst our isolates, and support that those sharing the large fljBA deletion could be more heterogeneous than previously anticipated. Full article

(This article belongs to the Special Issue The Evolution of Plasmid-Mediated Antimicrobial Resistance)

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16 pages, 989 KB

Open AccessEditor’s ChoiceArticle

Comparative Impact of an Optimized PK/PD Target Attainment of Piperacillin-Tazobactam vs. Meropenem on the Trend over Time of SOFA Score and Inflammatory Biomarkers in Critically Ill Patients Receiving Continuous Infusion Monotherapy for Treating Documented Gram-Negative BSIs and/or VAP

by Milo Gatti, Matteo Rinaldi, Tommaso Tonetti, Antonio Siniscalchi, Pierluigi Viale and Federico Pea

Antibiotics 2024, 13(4), 296; https://doi.org/10.3390/antibiotics13040296 - 25 Mar 2024

Cited by 2 | Viewed by 3047

Abstract

(1) Background: The advantage of using carbapenems over beta-lactam/beta-lactamase inhibitor combinations in critically ill septic patients still remains a debated issue. We aimed to assess the comparative impact of an optimized pharmacokinetic/pharmacodynamic (PK/PD) target attainment of piperacillin-tazobactam vs. meropenem on the trend over [...] Read more.

(1) Background: The advantage of using carbapenems over beta-lactam/beta-lactamase inhibitor combinations in critically ill septic patients still remains a debated issue. We aimed to assess the comparative impact of an optimized pharmacokinetic/pharmacodynamic (PK/PD) target attainment of piperacillin-tazobactam vs. meropenem on the trend over time of both Sequential Organ Failure Assessment (SOFA) score and inflammatory biomarkers in critically ill patients receiving continuous infusion (CI) monotherapy with piperacillin-tazobactam or meropenem for treating documented Gram-negative bloodstream infections (BSI) and/or ventilator-associated pneumonia (VAP). (2) Methods: We performed a retrospective observational study comparing critically ill patients receiving targeted treatment with CI meropenem monotherapy for documented Gram-negative BSIs or VAP with a historical cohort of critical patients receiving CI piperacillin-tazobactam monotherapy. Patients included in the two groups were admitted to the general and post-transplant intensive care unit in the period July 2021–September 2023 and fulfilled the same inclusion criteria. The delta values of the SOFA score between the baseline of meropenem or piperacillin-tazobactam treatment and those at 48-h (delta 48-h SOFA score) or at 7-days (delta 7-days SOFA) were selected as primary outcomes. Delta 48-h and 7-days C-reactive protein (CRP) and procalcitonin (PCT), microbiological eradication, resistance occurrence, clinical cure, multi-drug resistant colonization at 90-day, ICU, and 30-day mortality rate were selected as secondary outcomes. Univariate analysis comparing primary and secondary outcomes between critically ill patients receiving CI monotherapy with piperacillin-tazobactam vs. meropenem was carried out. (3) Results: Overall, 32 critically ill patients receiving CI meropenem monotherapy were compared with a historical cohort of 43 cases receiving CI piperacillin-tazobactam monotherapy. No significant differences in terms of demographics and clinical features emerged at baseline between the two groups. Optimal PK/PD target was attained in 83.7% and 100.0% of patients receiving piperacillin-tazobactam and meropenem, respectively. No significant differences were observed between groups in terms of median values of delta 48-h SOFA (0 points vs. 1 point; p = 0.89) and median delta 7-days SOFA (2 points vs. 1 point; p = 0.43). Similarly, no significant differences were found between patients receiving piperacillin-tazobactam vs. meropenem for any of the secondary outcomes. (4) Conclusion: Our findings may support the contention that in critically ill patients with documented Gram-negative BSIs and/or VAP, the decreases in the SOFA score and in the inflammatory biomarkers serum levels achievable with CI piperacillin-tazobactam monotherapy at 48-h and at 7-days may be of similar extent and as effective as to those achievable with CI meropenem monotherapy provided that optimization on real-time by means of a TDM-based expert clinical pharmacological advice program is granted. Full article

(This article belongs to the Special Issue Antibacterial Resistance and Infection Control in ICU)

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