Antibiotics

13 pages, 239 KiB

Open AccessArticle

Extended-Spectrum Beta-Lactamase Production and Carbapenem Resistance in Elderly Urinary Tract Infection Patients: A Multicenter Retrospective Study from Turkey

by Çiğdem Yıldırım, Sema Sarı, Ayşe Merve Parmaksızoğlu Aydın, Aysin Kilinç Toker, Ayşe Turunç Özdemir, Esra Erdem Kıvrak, Sinan Mermer, Hasip Kahraman, Orçun Soysal, Hasan Çağrı Yıldırım and Meltem Isikgoz Tasbakan

Antibiotics 2025, 14(7), 719; https://doi.org/10.3390/antibiotics14070719 (registering DOI) - 17 Jul 2025

Abstract

Introduction: Urinary tract infections (UTIs) remain a significant public health issue worldwide, particularly affecting the geriatric population with increased morbidity and mortality. Aging-related immune changes, comorbidities, and urogenital abnormalities contribute to the higher incidence and complexity of UTIs in elderly patients. Antimicrobial resistance, [...] Read more.

Introduction: Urinary tract infections (UTIs) remain a significant public health issue worldwide, particularly affecting the geriatric population with increased morbidity and mortality. Aging-related immune changes, comorbidities, and urogenital abnormalities contribute to the higher incidence and complexity of UTIs in elderly patients. Antimicrobial resistance, especially extended-spectrum beta-lactamase (ESBL) production and carbapenem resistance, poses a major challenge in managing UTIs in this group. Methods: This retrospective, multicenter study included 776 patients aged 65 and older, hospitalized with a diagnosis of urinary tract infection between January 2019 and August 2024. Clinical, laboratory, and microbiological data were collected and analyzed. Urine samples were obtained under sterile conditions and pathogens identified using conventional and automated systems. Antibiotic susceptibility testing was performed according to CLSI standards. Logistic regression analyses were conducted to identify factors associated with ESBL production, carbapenem resistance, and mortality. Results: Among the patients, the median age was 78.9 years, with 45.5% female. ESBL production was detected in 56.8% of E. coli isolates and carbapenem resistance in 1.2%. Klebsiella species exhibited higher carbapenem resistance (37.8%). Independent predictors of ESBL production included the presence of urogenital cancer and antibiotic use within the past three months. Carbapenem resistance was associated with recent hospitalization, absence of kidney stones, and infection with non-E. coli pathogens. Mortality was independently associated with intensive care admission at presentation, altered mental status, Gram-positive infections, and comorbidities such as chronic obstructive pulmonary disease and urinary incontinence. Discussion: Our findings suggest that urinary pathogens and resistance patterns in elderly patients are similar to those in younger adults reported in the literature, highlighting the need for age-specific awareness in empiric therapy. The identification of risk factors for multidrug-resistant organisms emphasizes the importance of targeted antibiotic stewardship, especially in high-risk geriatric populations. Multicenter data contribute to regional understanding of resistance trends, aiding clinicians in optimizing management strategies for elderly patients with UTIs. Conclusions: This study highlights that E. coli and Klebsiella species are the primary causes of UTIs in the elderly, with resistance patterns similar to those seen in younger adults. The findings also contribute important data on risk factors for ESBL production and carbapenem resistance, supported by a robust patient sample. Full article

32 pages, 2479 KiB

Open AccessReview

Fungal Biofilm: An Overview of the Latest Nano-Strategies

by Andrea Giammarino, Laura Verdolini, Giovanna Simonetti and Letizia Angiolella

Antibiotics 2025, 14(7), 718; https://doi.org/10.3390/antibiotics14070718 (registering DOI) - 17 Jul 2025

Abstract

Background/Objectives: There is an increasing incidence of fungal infections in conjunction with the rise in resistance to medical treatment. Antimicrobial resistance is frequently associated with virulence factors such as adherence and the capacity of biofilm formation, which facilitates the evasion of the [...] Read more.

Background/Objectives: There is an increasing incidence of fungal infections in conjunction with the rise in resistance to medical treatment. Antimicrobial resistance is frequently associated with virulence factors such as adherence and the capacity of biofilm formation, which facilitates the evasion of the host immune response and resistance to drug action. Novel therapeutic strategies have been developed to overcome antimicrobial resistance, including the use of different type of nanomaterials: metallic (Au, Ag, Fe₃O₄ and ZnO), organic (e.g., chitosan, liposomes and lactic acid) or carbon-based (e.g., quantum dots, nanotubes and graphene) materials. The objective of this study was to evaluate the action of nanoparticles of different synthesis and with different coatings on fungi of medical interest. Methods: Literature research was conducted using PubMed and Google Scholar databases, and the following terms were employed in articles published up to June 2025: ‘nanoparticles’ in combination with ‘fungal biofilm’, ‘Candida biofilm’, ‘Aspergillus biofilm’, ‘Cryptococcus biofilm’, ‘Fusarium biofilm’ and ‘dermatophytes biofilm’. Results: The utilization of nanoparticles was found to exert a substantial impact on the reduction in fungal biofilm, despite the presence of substantial variability in minimum inhibitory concentration (MIC) values attributable to variations in nanoparticle type and the presence of capping agents. It was observed that the MIC values were lower for metallic nanoparticles, particularly silver, and for those synthesized with polylactic acid compared to the others. Conclusions: Despite the limited availability of data concerning the stability and biocompatibility of nanoparticles employed in the treatment of fungal biofilms, it can be posited that these results constitute a significant initial step. Full article

(This article belongs to the Special Issue Methods for Preventing Biofilm Formation and Treat the Infections Caused by Biofilm Formed on Biotics or Abiotic Surfaces)

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15 pages, 636 KiB

Open AccessArticle

High Prevalence of Multidrug-Resistant Bacterial Colonization Among Patients and Healthcare Workers in a Rural Ethiopian Hospital

by Elena Hidalgo, Teresa Alvaredo-Carrillo, Josefina-Marina Gil-Belda, Clara Portela-Pino, Clara Bares-Moreno, Sara Jareño-Moreno, Paula de la Fuente, Lucía Platero and Ramón Pérez-Tanoira

Antibiotics 2025, 14(7), 717; https://doi.org/10.3390/antibiotics14070717 (registering DOI) - 17 Jul 2025

Abstract

Background/Objectives: Multidrug-resistant (MDR) bacterial colonization poses a significant risk for subsequent infections, especially within hospital environments. Healthcare workers can inadvertently transmit these MDR bacteria to vulnerable patients, exacerbating the problem. This study aimed to determine the colonization rates of MDR bacteria among patients [...] Read more.

Background/Objectives: Multidrug-resistant (MDR) bacterial colonization poses a significant risk for subsequent infections, especially within hospital environments. Healthcare workers can inadvertently transmit these MDR bacteria to vulnerable patients, exacerbating the problem. This study aimed to determine the colonization rates of MDR bacteria among patients and healthcare workers in a rural Ethiopian hospital with limited resources. Methods: Between 26 May and 6 June 2024, nasal, rectal, vagino-rectal exudate, and stool samples were collected from patients (n = 78) and healthcare workers (n = 11) at Gambo General Hospital (Oromia Region, Ethiopia). Samples were cultured on chromogenic media selective for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), and carbapenemase-producing Enterobacteriaceae (CPE). Bacterial identification was performed using MALDI-TOF mass spectrometry (Bruker), antimicrobial susceptibility testing using the MicroScan WalkAway system (Beckman Coulter), and genotypic characterization with the MDR Direct Flow Chip kit (Vitro). Results: MRSA nasal colonization was detected in 43.3% of patients (13/30; 95% CI: 27.4–60.8%) and 27.3% of healthcare workers (3/11; 95% CI: 6.0–61.0%) (p = 0.73). Rectal (or stool) colonization by MDR bacteria was significantly higher in pediatric patients (85.0%, 17/20; 95% CI: 62.1–96.8%) than in adults (14.3%, 4/28; 95% CI: 5.7–31.5%) (p < 0.001). Notably, a high proportion of pediatric patients harbored Escherichia coli strains co-producing NDM carbapenemase and CTX-M ESBL, and VRE strains were also predominantly isolated in this group. Conclusions: This study reveals a concerningly high prevalence of MRSA and MDR Enterobacteriaceae, especially among children at Gambo Hospital. The VRE prevalence was also substantially elevated compared to other studies. These findings underscore the urgent need for strengthened infection control measures and antimicrobial stewardship programs within the hospital setting. Full article

(This article belongs to the Special Issue Gram-Negative Multidrug-Resistant Pathogens and Their Treatment, 2nd Edition)

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11 pages, 511 KiB

Open AccessArticle

Effects of Antibiotic De-Escalation on Outcomes in Severe Community-Acquired Pneumonia: An Inverse Propensity Score-Weighted Analysis

by Diego Viasus, Gabriela Abelenda-Alonso, Juan Bolivar-Areiza, Carlota Gudiol and Jordi Carratalà

Antibiotics 2025, 14(7), 716; https://doi.org/10.3390/antibiotics14070716 (registering DOI) - 17 Jul 2025

Abstract

Objective: This study aimed to assess the effect of antibiotic de-escalation on 30-day mortality, duration of intravenous (IV) antibiotic therapy and length of hospital stay (LOS) in severe community-acquired pneumonia (sCAP). Methods: We performed a retrospective analysis of prospectively collected data [...] Read more.

Objective: This study aimed to assess the effect of antibiotic de-escalation on 30-day mortality, duration of intravenous (IV) antibiotic therapy and length of hospital stay (LOS) in severe community-acquired pneumonia (sCAP). Methods: We performed a retrospective analysis of prospectively collected data from a cohort of adults diagnosed with sCAP and microbiologically confirmed etiology between 1995 to 2022. Two distinct time points of the de-escalation were analyzed: 3 and 6 days post-admission, corresponding, respectively, to the availability of microbiological results and the median time to clinical stability. Inverse propensity score-weighted binary logistic regression was used to adjust for potential confounders. Results: A total of 398 consecutive cases of sCAP were analyzed. No significant differences were observed between the de-escalation and non-de-escalation groups in terms of age, sex, comorbidities, or severity-related variables (such as impaired consciousness, shock, respiratory failure, or multilobar pneumonia). Patients in the de-escalation group had lower rates of leukopenia, bacteremia and empyema, and less need for mechanical ventilation, with variations depending on the timing of de-escalation. After adjusting for confounding factors in an inverse propensity score-weighted analysis, de-escalation within 3 or 6 days after admission was not associated with increased mortality risk (adjusted odds ratio [aOR] 1.48, 95% confidence interval [CI] 0.29–7.4; p = 0.63, and aOR 0.57, 95% CI 0.14–2.31, p = 0.43, respectively). Similar findings were observed for prolonged LOS. However, antibiotic de-escalation was related to a lower risk of prolonged IV antibiotic. Conclusions: Antibiotic de-escalation in microbiologically confirmed sCAP did not negatively impact clinical outcomes, supporting the safety of this strategy for optimizing antibiotic use in this serious infection. Full article

(This article belongs to the Special Issue Therapy of Infectious Diseases Among Children and Adults: The Role of Antibiotics in Daily Practice)

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11 pages, 809 KiB

Open AccessArticle

Antimicrobial Behavior of Surface-Treated Commercially Pure Titanium (CpTi) for Dental Implants in Artificial Saliva—In Vitro Study

by Roshni Bopanna, Neetha J. Shetty, Ashith M. Varadaraj, Himani Kotian, Sameep Shetty and Simran Genescia

Antibiotics 2025, 14(7), 715; https://doi.org/10.3390/antibiotics14070715 - 16 Jul 2025

Abstract

Background/Objectives:Titanium implant surface modifications enhance osseointegration and prevent microbial colonization, improving implant longevity. Antimicrobial coatings, particularly cerium- and bismuth-doped hydroxyapatite (CeHAp and BiHAp), have gained attention for reducing infection-related complications. This study evaluates the antimicrobial activity of CeHAp and BiHAp coatings on [...] Read more.

Background/Objectives:Titanium implant surface modifications enhance osseointegration and prevent microbial colonization, improving implant longevity. Antimicrobial coatings, particularly cerium- and bismuth-doped hydroxyapatite (CeHAp and BiHAp), have gained attention for reducing infection-related complications. This study evaluates the antimicrobial activity of CeHAp and BiHAp coatings on CpTi compared to untreated CpTi in artificial saliva at pH levels of 4.5, 6.5, and 8. Methods: Antibacterial efficacy against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Candida albicans (C. albicans) was assessed using the broth dilution method. Titanium rods coated with test compounds were incubated in inoculated nutrient broth, and microbial inhibition was determined via optical density at 600 nm. A statistical analysis was performed using the Kruskal–Wallis ANOVA test, the median and Interquartile Range were determined for the variables, and a Dwass–Steel–Critchlow–Fligner intergroup pairwise comparison was conducted. Results: The results showed that both the CeHAp and BiHAp coatings demonstrated significant antimicrobial activity against S. aureus (OD = 0.01) at pH 6.5, which was more pronounced than the activity observed against E. coli (OD = 0.05), with the difference being statistically significant (p = 0.001). The least antimicrobial activity was observed against C. albicans (0.21) at pH 8 (p = 0.001). Conclusion: These findings highlight the pH-dependent effectiveness of BiHAp and CeHAp coatings in inhibiting microbial growth. Their application on titanium implants may enhance antimicrobial properties, contributing to improved dental implant success and broader biomedical applications. Full article

(This article belongs to the Section Antimicrobial Materials and Surfaces)

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11 pages, 2797 KiB

Open AccessArticle

Illuminating the Invisible: Green Fluorescent Protein as a Beacon for Antibiotic-Induced Phage Activity in Escherichia coli

by Maria João Silva, Tim Van Den Bossche, Mattias Collin and Rolf Lood

Antibiotics 2025, 14(7), 714; https://doi.org/10.3390/antibiotics14070714 (registering DOI) - 16 Jul 2025

Abstract

Background/Objectives: Antibiotic resistance presents an urgent public health threat. By developing a streamlined and effective method for studying bacteriophage induction, this research marks a step further in understanding how antibiotic-resistant genes might spread across different environments. This knowledge is essential for creating strategies [...] Read more.

Background/Objectives: Antibiotic resistance presents an urgent public health threat. By developing a streamlined and effective method for studying bacteriophage induction, this research marks a step further in understanding how antibiotic-resistant genes might spread across different environments. This knowledge is essential for creating strategies to reduce the spread of antimicrobial resistance (AMR), particularly from a One Health perspective. In this study, we develop and validate a Green Fluorescent Protein (GFP)-based method as a proxy for bacteriophage induction. This method screens compounds for their potential to promote bacteriophage induction. Methods: This study utilized a recA-GFP construct in Escherichia coli to measure fluorescence as an indicator of SOS response activation. The experiments involved treating E. coli cultures with varying concentrations of the DNA-damaging chemical mitomycin C and measuring fluorescence over time. Additionally, droplet digital PCR (ddPCR) quantified bacteriophage induction in a lambda phage-carrying E. coli strain, allowing for correlation analysis between the two methods. Results: The recA-driven SOS response depended on both dose and time, with increasing concentrations of mitomycin C leading to higher fluorescence. ddPCR analysis confirmed that mitomycin C induced prophage activation, with gene ratios increasing at higher drug concentrations over time. A strong Spearman correlation (>0.7) was noted between fluorescence and ddPCR results at elevated concentrations and relevant time points, indicating the validity of the GFP-based model as a proxy for bacteriophage induction. Conclusions: The findings demonstrate a strong association between the two methods of measuring phage induction, suggesting that the GFP-based E. coli model is a reliable, cost-effective, and efficient tool for studying phage induction and its potential role in AMR spread. This method could facilitate the screening of environmental samples and specific drugs to evaluate their impact on bacteriophage induction, which opens the door for applications such as screening for antibiotic resistance dissemination. Full article

(This article belongs to the Section Bacteriophages)

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22 pages, 3103 KiB

Open AccessArticle

Genomic and Metabolomic Analysis of the Endophytic Fungus Alternaria alstroemeriae S6 Isolated from Veronica acinifolia: Identification of Anti-Bacterial Properties and Production of Succinic Acid

by Farkhod Eshboev, Alex X. Gao, Akhror Abdurashidov, Kamila Mardieva, Asadali Baymirzaev, Mirzatimur Musakhanov, Elvira Yusupova, Shengying Lin, Meixia Yang, Tina T. X. Dong, Shamansur Sagdullaev, Shakhnoz Azimova and Karl W. K. Tsim

Antibiotics 2025, 14(7), 713; https://doi.org/10.3390/antibiotics14070713 - 16 Jul 2025

Abstract

Background: Endophytic fungi are prolific sources of bioactive metabolites with potential in pharmaceutical and biotechnological applications. Methods: Here, the endophytic fungus, Alternaria alstroemeriae S6, was isolated from Veronica acinifolia (speedwell), and conducted its anti-microbial activities, whole-genome sequencing and metabolome analysis. Results: The ethyl [...] Read more.

Background: Endophytic fungi are prolific sources of bioactive metabolites with potential in pharmaceutical and biotechnological applications. Methods: Here, the endophytic fungus, Alternaria alstroemeriae S6, was isolated from Veronica acinifolia (speedwell), and conducted its anti-microbial activities, whole-genome sequencing and metabolome analysis. Results: The ethyl acetate extract of this fungus exhibited strong anti-bacterial activity and the inhibition zones, induced by the fungal extract at 20 mg/mL, reached 16.25 ± 0.5 mm and 26.5 ± 0.5 mm against Gram-positive and Gram-negative bacteria. To unravel the biosynthetic potential for anti-bacterial compounds, whole-genome sequencing was conducted on A. alstroemeriae S6, resulting in a high-quality assembly of 42.93 Mb encoding 13,885 protein-coding genes. Comprehensive functional genome annotation analyses, including gene ontology (GO) terms, clusters of orthologous groups (COGs), Kyoto encyclopedia of genes and genomes (KEGG), carbohydrate-active enzymes (CAZymes), and antibiotics and secondary metabolites analysis shell (antiSMASH) analyses, were performed. According to the antiSMASH analysis, 58 biosynthetic gene clusters (BGCs), including 16 non-ribosomal peptide synthetases (NRPSs), 21 terpene synthases, 12 polyketide synthetases (PKSs), and 9 hybrids, were identified. In addition, succinic acid was identified as the major metabolite within the fungal extract, while 20 minor bioactive compounds were identified through LC-MS/MS-based molecular networking on a GNPS database. Conclusions: These findings support the biotechnological potential of A. alstroemeriae S6 as an alternative producer of succinic acid, as well as novel anti-bacterial agents. Full article

(This article belongs to the Section Fungi and Their Metabolites)

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11 pages, 869 KiB

Open AccessArticle

Species Distribution, Characterization, and Antifungal Susceptibility Patterns of Candida Isolates Causing Oral and Vulvovaginal Candidiasis in Chile

by Francisca Nahuelcura and Eduardo Álvarez Duarte

Antibiotics 2025, 14(7), 712; https://doi.org/10.3390/antibiotics14070712 - 16 Jul 2025

Abstract

Background: Oral candidiasis (OC) and vulvovaginal candidiasis (VVC) are infections caused by species belonging to the genus Candida. In Chile, epidemiological studies on OC/VVC are scarce, leading to an overestimation of the prevalence of C. albicans. Additionally, awareness of the prevalence [...] Read more.

Background: Oral candidiasis (OC) and vulvovaginal candidiasis (VVC) are infections caused by species belonging to the genus Candida. In Chile, epidemiological studies on OC/VVC are scarce, leading to an overestimation of the prevalence of C. albicans. Additionally, awareness of the prevalence of species phenotypically and genotypically similar to C. albicans is lacking. The clinical impact of non-albicans species in cases of OC/VVC is also often underestimated. This study aims to determine the distribution of Candida species, their phenotypic and molecular characteristics, and their antifungal susceptibility patterns in incidents of oral and vulvovaginal candidiasis in Chile. Methods: A descriptive analysis was conducted on 101 isolates of Candida spp. obtained from OC/VVC cases. The identification of Candida species was performed using both phenotypic and molecular techniques. Antifungal susceptibility testing was carried out using the Sensititre YeastOne system. Results: Among the analyzed isolates, 89.1% were identified as C. albicans, while 10.9% were categorized as non-albicans species, including C. dubliniensis, C. glabrata sensu stricto, C. bracarensis, C. tropicalis, C. lusitaniae, and C. parapsilosis sensu stricto. The susceptibility pattern was predominantly susceptible, with only 10.9% of the total strains demonstrating resistance, and low antifungal activity in vitro was observed for Fluconazole, Voriconazole, and Posaconazole. Conclusions: The most prevalent species causing OC/VVC in Chile is C. albicans. This study also presents the first report of C. lusitaniae as a causal agent of VVC in the country. The identification of azole-resistant strains emphasizes the critical role of laboratory diagnosis in VVC cases, thereby preventing potential treatment failures. No resistance was observed in the strains associated with OC. Full article

(This article belongs to the Special Issue Epidemiology, Antifungal Resistance and Therapy in Fungal Infection)

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16 pages, 1988 KiB

Open AccessArticle

Epidemiological Surveillance, Variability, and Evolution of Isolates Belonging to the Spanish Clone of the 4,[5],12:i:- Monophasic Variant of Salmonella enterica Serovar Typhimurium

by Xenia Vázquez, Patricia García, Javier Fernández, Víctor Ladero, Carlos Rodríguez-Lucas, Jürgen J. Heinisch, Rosaura Rodicio and M. Rosario Rodicio

Antibiotics 2025, 14(7), 711; https://doi.org/10.3390/antibiotics14070711 - 16 Jul 2025

Abstract

Background/Objective: The present study focused on the analysis of the Spanish clone belonging to the successful 4,[5],12:i:- monophasic variant of Salmonella enterica serovar Typhimurium. Methods: All isolates of the clone recovered in a Spanish region from human clinical samples between 2008 and 2018 [...] Read more.

Background/Objective: The present study focused on the analysis of the Spanish clone belonging to the successful 4,[5],12:i:- monophasic variant of Salmonella enterica serovar Typhimurium. Methods: All isolates of the clone recovered in a Spanish region from human clinical samples between 2008 and 2018 (N = 14) were investigated using microbiological approaches and genome sequence analysis. In addition, they were compared with isolates from the years 2000 to 2003 (N = 21), which were previously characterized but had not yet been sequenced. Results: Phylogenetic analyses indicate that all isolates are closely related (differing by 1 to 103 SNPs) but belong to two clades termed A and B. With few exceptions, clade A comprised isolates of the first period, also including two “older” control strains, LSP 389/97 and LSP 272/98. Clade B only contained isolates from the second period. Isolates from both periods were resistant to antibiotics and biocides, with almost all resistance genes located on large IncC plasmids, additionally carrying pSLT-derived virulence genes. The number of resistance genes was highly variable, resulting in a total of 22 ABR (antibiotic biocide resistance) profiles. The number of antibiotic resistance genes, but not that of biocide resistance genes, was considerably lower in isolates from the second than from the first period (with averages of 5.5 versus 9.6 genes). Importantly, IS26, which resides in multiple copies within these plasmids, appears to be playing a crucial role in the evolution of resistance, and it was also responsible for the monophasic phenotype, which was associated with four different deletions eliminating the fljAB region. Conclusions: the observed reduction in the number of antibiotic resistance genes could correlate with the loss of adaptive advantage originating from the ban on the use of antibiotics as feed additives implemented in the European Union since 2006, facilitated by the intrinsic instability of the IncC plasmids. Two consecutive IS26 transposition events, which can explain both the clonal relationship of the isolates and their variability, may account for the observed fljAB deletions. Full article

(This article belongs to the Special Issue Genomic Analysis of Antimicrobial Drug-Resistant Bacteria)

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2 pages, 133 KiB

Open AccessCorrection

Correction: Honegger et al. Antimicrobial Efficacy of Five Wound Irrigation Solutions in the Biofilm Microenvironment In Vitro and Ex Vivo. Antibiotics 2025, 14, 25

by Anja L. Honegger, Tiziano A. Schweizer, Yvonne Achermann and Philipp P. Bosshard

Antibiotics 2025, 14(7), 710; https://doi.org/10.3390/antibiotics14070710 - 16 Jul 2025

Abstract

There was an error in the original publication [...] Full article

19 pages, 368 KiB

Open AccessArticle

Barriers to Compliance with National Guidelines Among Children Hospitalized with Community-Acquired Pneumonia in Vietnam and the Implications

by Thuy Thi Phuong Nguyen, Huong Thi Thu Vu, Anh Minh Hoang, An Minh Ho, Israel Abebrese Sefah, Brian Godman and Johanna C. Meyer

Antibiotics 2025, 14(7), 709; https://doi.org/10.3390/antibiotics14070709 (registering DOI) - 15 Jul 2025

Abstract

Background: Community-acquired pneumonia (CAP) is the leading cause of death in infants aged 1–59 months. Concurrent with this, there is a need to prescribe antibiotics wisely in Vietnam due to concerns with rising antimicrobial resistance (AMR). Consequently, an urgent need has arisen [...] Read more.

Background: Community-acquired pneumonia (CAP) is the leading cause of death in infants aged 1–59 months. Concurrent with this, there is a need to prescribe antibiotics wisely in Vietnam due to concerns with rising antimicrobial resistance (AMR). Consequently, an urgent need has arisen to treat patients according to agreed guidelines. The aim of this study was to investigate the current management of infants under five years old with CAP in Vietnam as well as identify possible obstacles to adhering to national guidelines. Methods: A mixed-method approach was used incorporating both quantitative and qualitative data analysis in a leading hospital in Vietnam, which influences others. Data from 108 pediatric patient records were collected and analyzed. Subsequently, in-depth interviews were conducted with pediatric doctors treating these patients to ascertain possible reasons for non-adherence to guidelines. Results: The mean age of children diagnosed with CAP was 27.94 ± 12.99 months, with 82.4% having non-severe CAP, and 41.7% of children had previously used antibiotics before hospitalization. The median length of hospital stay was 7 days. All children were prescribed antibiotics, 91.4% of children received these initially intravenously, with third-generation cephalosporins being the most (91.7%) commonly prescribed. Cefoperazone/sulbactam was the most frequently prescribed (48.2%) antibiotic. However, on 96.1% of occasions cefoperazone/sulbactam was given at higher doses than the label instructions. Overall, 73.3% of antibiotics prescribed were “Watch” antibiotics. In addition, the proportion of initial antibiotic regimens that were consistent with current national guidelines was only 4.63%. Conclusions: There were considerable concerns with low adherence rates to current guidelines alongside high rates of prescribing of injectable third-generation cephalosporins due to various internal and external barriers. Antimicrobial stewardship programs with updated national guidelines are urgently needed in Vietnamese hospitals to treat CAP in children as part of ongoing measures to reduce increasing AMR rates. Such activities should also help improve antibiotic use in the community following improved education of trainee ambulatory care physicians regarding appropriate management of children with CAP. Full article

(This article belongs to the Special Issue Antibiotic Resistance: From the Bench to Patients, 2nd Edition)

15 pages, 633 KiB

Open AccessArticle

Performance of Early Sepsis Screening Tools for Timely Diagnosis and Antibiotic Stewardship in a Resource-Limited Thai Community Hospital

by Wisanu Wanlumkhao, Duangduan Rattanamongkolgul and Chatchai Ekpanyaskul

Antibiotics 2025, 14(7), 708; https://doi.org/10.3390/antibiotics14070708 - 15 Jul 2025

Abstract

Background: Early identification of sepsis is critical for improving outcomes, particularly in low-resource emergency settings. In Thai community hospitals, where physicians may not always be available, triage is often nurse-led. Selecting accurate and practical sepsis screening tools is essential not only for timely [...] Read more.

Background: Early identification of sepsis is critical for improving outcomes, particularly in low-resource emergency settings. In Thai community hospitals, where physicians may not always be available, triage is often nurse-led. Selecting accurate and practical sepsis screening tools is essential not only for timely clinical decision-making but also for timely diagnosis and promoting appropriate antibiotic use. Methods: This cross-sectional study analyzed 475 adult patients with suspected sepsis who presented to the emergency department of a Thai community hospital, using retrospective data from January 2021 to December 2022. Six screening tools were evaluated: Systemic Inflammatory Response Syndrome (SIRS), Quick Sequential Organ Failure Assessment (qSOFA), Modified Early Warning Score (MEWS), National Early Warning Score (NEWS), National Early Warning Score version 2 (NEWS2), and Search Out Severity (SOS). Diagnostic accuracy was assessed using International Classification of Diseases, Tenth Revision (ICD-10) codes as the reference standard. Performance metrics included sensitivity, specificity, predictive values, likelihood ratios, and the area under the receiver operating characteristic (AUROC) curve, all reported with 95% confidence intervals. Results: SIRS had the highest sensitivity (84%), while qSOFA demonstrated the highest specificity (91%). NEWS2, NEWS, and MEWS showed moderate and balanced diagnostic accuracy. SOS also demonstrated moderate accuracy. Conclusions: A two-step screening approach—using SIRS for initial triage followed by NEWS2 for confirmation—is recommended. This strategy enhances nurse-led screening and optimizes limited resources in emergency care. Early sepsis detection through accurate screening tools constitutes a feasible public health intervention to support appropriate antibiotic use and mitigate antimicrobial resistance, especially in resource-limited community hospital settings. Full article

(This article belongs to the Special Issue Antimicrobial Prescribing, Population Use and Resistance, Impact in Global Health, 3rd Edition)

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14 pages, 1574 KiB

Open AccessArticle

Antimicrobial Efficacy of Impregnated Human Acellular Dermal Substitutes in Burn Wound Models

by Marianna Hajská, Elena Kurin, Silvia Bittner Fialová, Marian Vidiščák and Arpád Panyko

Antibiotics 2025, 14(7), 707; https://doi.org/10.3390/antibiotics14070707 - 14 Jul 2025

Abstract

Burn wound infections remain a major clinical challenge due to delayed healing, scarring, and the risk of sepsis, especially when complicated by multidrug-resistant (MDR) Gram-negative pathogens and biofilm formation. Acellular dermal matrices (ADMs) are widely used in reconstructive and burn surgery, yet they [...] Read more.

Burn wound infections remain a major clinical challenge due to delayed healing, scarring, and the risk of sepsis, especially when complicated by multidrug-resistant (MDR) Gram-negative pathogens and biofilm formation. Acellular dermal matrices (ADMs) are widely used in reconstructive and burn surgery, yet they lack intrinsic antimicrobial activity, necessitating their combination with topical agents. Background/Objectives: This study investigates the antimicrobial and cytocompatibility profiles of ADMs impregnated with various antimicrobial agents, using in vitro planktonic and biofilm burn wound models. While the incorporation of antimicrobials into scaffolds has been previously explored, this study is, to our knowledge, the first to directly compare seven clinically relevant antimicrobial agents after they were impregnated into an ADM in a standardized in vitro model. Methods: Seven topical antimicrobials were tested against MDR Pseudomonas aeruginosa and Acinetobacter baumannii from burn patients. Results: The ADM with 1% acetic acid (AA) showed superior antimicrobial activity, achieving > 7 log₁₀ reductions in planktonic assays and complete inhibition of P. aeruginosa biofilms. In NIH 3T3 fibroblast cytotoxicity assays, the 1% AA ADM maintained cell viability at control levels, indicating excellent biocompatibility. Compared with agents such as Betadine^®, Octenilin^®, and colistin, which showed cytotoxicity, and Prontosan^®, which showed low efficacy, 1% AA uniquely combined potent antibacterial effects with minimal toxicity. Conclusions: Among the seven antimicrobial agents impregnated into ADMs, 1% AA demonstrated a unique efficacy and safety profile, supporting its potential for clinical application in integrated wound dressings and implantable biomaterials for infection control in burn care. Full article

(This article belongs to the Special Issue Antimicrobial Resistance and Therapy in Intensive Care Unit)

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15 pages, 2742 KiB

Open AccessArticle

Resistome and Phylogenomics of Escherichia coli Strains Obtained from Diverse Sources in Jimma, Ethiopia

by Mulatu Gashaw, Esayas Kebede Gudina, Guenter Froeschl, Ralph Matar, Solomon Ali, Liegl Gabriele, Amelie Hohensee, Thomas Seeholzer, Arne Kroidl and Andreas Wieser

Antibiotics 2025, 14(7), 706; https://doi.org/10.3390/antibiotics14070706 - 14 Jul 2025

Abstract

Introduction: In recent years, antimicrobial resistance (AMR) rates have increased significantly in bacterial pathogens, particularly extended beta-lactam resistance. This study aimed to investigate resistome and phylogenomics of Escherichia coli (E. coli) strains isolated from various sources in Jimma, Ethiopia. Methods [...] Read more.

Introduction: In recent years, antimicrobial resistance (AMR) rates have increased significantly in bacterial pathogens, particularly extended beta-lactam resistance. This study aimed to investigate resistome and phylogenomics of Escherichia coli (E. coli) strains isolated from various sources in Jimma, Ethiopia. Methods: Phenotypic antibiotic resistance patterns of E. coli isolates were determined using automated Kirby–Bauer disc diffusion and minimum inhibitory concentration (MIC). Isolates exhibiting phenotypic resistance to beta-lactam antibiotics were further analyzed with a DNA microarray to confirm the presence of resistance-encoding genes. Additionally, multilocus sequence typing (MLST) of seven housekeeping genes was conducted using PCR and Oxford Nanopore-Technology (ONT) to assess the phylogenetic relationships among the E. coli isolates. Results: A total of 611 E. coli isolates from human, animal, and environmental sources were analyzed. Of these, 41.6% (254) showed phenotypic resistance to at least one of the tested beta-lactams, 96.1% (244) thereof were confirmed genotypically. More than half of the isolates (53.3%) had two or more resistance genes present. The most frequent ESBL-encoding gene was CTX-M-15 (74.2%; 181), followed by TEM (59.4%; 145) and CTX-M-9 (4.1%; 10). The predominant carbapenemase gene was NDM-1, detected in 80% (12 out of 15) of carbapenem-resistant isolates. A phylogenetic analysis revealed clonality among the strains obtained from various sources, with international high-risk clones such as ST131, ST648, ST38, ST73, and ST405 identified across various niches. Conclusions: The high prevalence of CTX-M-15 and NDM-1 in multidrug-resistant E. coli isolates indicates the growing threat of AMR in Ethiopia. The discovery of these high-risk clones in various niches shows possible routes of transmission and highlights the necessity of a One Health approach to intervention and surveillance. Strengthening antimicrobial stewardship, infection prevention, and control measures are crucial to mitigate the spread of these resistant strains. Full article

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18 pages, 333 KiB

Open AccessReview

Antibiotic Elution from Cement Spacers and Its Influencing Factors

by Bernd Fink and Kevin D. Tetsworth

Antibiotics 2025, 14(7), 705; https://doi.org/10.3390/antibiotics14070705 - 14 Jul 2025

Abstract

Antibiotic-loaded cement spacers play a crucial role in two-stage revision arthroplasty of infected total hip and knee prostheses. There is still controversy regarding whether the elution from antibiotic-loaded cement spacers is greater than the MIC for a prolonged time between stages. Therefore, the [...] Read more.

Antibiotic-loaded cement spacers play a crucial role in two-stage revision arthroplasty of infected total hip and knee prostheses. There is still controversy regarding whether the elution from antibiotic-loaded cement spacers is greater than the MIC for a prolonged time between stages. Therefore, the aim of the current review was to determine how long spacers elute antibiotics above the MIC for most causative microorganisms, as well as to evaluate what factors influence that elution. Independent of methodological differences and weaknesses of the studies themselves, several study results indicate that after an early peak of antibiotic release from the spacer in the first 1 to 2 days (followed by a gradual decline), a sufficient release above the MIC for most causative bacteria continues for 6 to 12 weeks. Full article

(This article belongs to the Special Issue Diagnostics, Antibiotic Usage and Surgery Related Techniques in Prevention and Treatment of Prosthetic Joint and Implant Related Infections)

13 pages, 1556 KiB

Open AccessArticle

Investigation of WQ-3810, a Fluoroquinolone with a High Potential Against Fluoroquinolone-Resistant Mycobacterium avium

by Sasini Jayaweera, Pondpan Suwanthada, David Atomanyi Barnes, Charlotte Poussier, Tomoyasu Nishimura, Naoki Hasegawa, Yukiko Nishiuchi, Jeewan Thapa, Stephen V. Gordon, Hyun Kim, Chie Nakajima and Yasuhiko Suzuki

Antibiotics 2025, 14(7), 704; https://doi.org/10.3390/antibiotics14070704 - 14 Jul 2025

Abstract

Background/Objectives: Mycobacterium avium, a member of Mycobacterium avium complex (MAC), is an emerging opportunistic pathogen causing MAC-pulmonary disease (PD). Fluoroquinolones (FQs), along with ethambutol (EMB) and rifampicin, are recommended for macrolide-resistant MAC-PD; however, FQ-resistant M. avium have been reported worldwide. WQ-3810 [...] Read more.

Background/Objectives: Mycobacterium avium, a member of Mycobacterium avium complex (MAC), is an emerging opportunistic pathogen causing MAC-pulmonary disease (PD). Fluoroquinolones (FQs), along with ethambutol (EMB) and rifampicin, are recommended for macrolide-resistant MAC-PD; however, FQ-resistant M. avium have been reported worldwide. WQ-3810 is an FQ with high potency against FQ-resistant pathogens; however, its activity against M. avium has not yet been studied. Methods: In this study, we conducted a DNA supercoiling inhibitory assay to evaluate the inhibitory effect of WQ-3810 on recombinant wild-type (WT) and four mutant DNA gyrases of M. avium and compared the IC₅₀s of WQ-3810 with those of ciprofloxacin (CIP), levofloxacin (LVX), and moxifloxacin (MXF). In addition, we examined WQ-3810’s antimicrobial activity against 11 M. avium clinical isolates, including FQ-resistant isolates, with that of other FQs. Furthermore, we assessed the synergistic action of WQ-3810 with the combination of either EMB or isoniazid (INH). Results: In a DNA supercoiling inhibitory assay, WQ-3810 showed 1.8 to 13.7-fold higher efficacy than LVX and CIP. In the MIC assay, WQ-3810 showed 4 to 8-fold, 2 to 16-fold, and 2 to 4-fold higher antimicrobial activity against FQ-resistant isolates than CIP, LVX, and MXF, respectively. The combination of WQ-3810 and INH exhibited a synergistic relationship. Conclusions: The overall characteristics of WQ-3810 demonstrated greater effectiveness than three other FQs, suggesting that it is a promising option for treating FQ-resistant M. avium infections. Full article

(This article belongs to the Special Issue Genomic Characterization of Antimicrobial Resistance and Evolution Mechanism of Bacteria)

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21 pages, 1308 KiB

Open AccessArticle

Mechanisms of Cefiderocol Resistance in Carbapenemase-Producing Enterobacterales: Insights from Comparative Genomics

by Alexander Tristancho-Baró, Ana Isabel López-Calleja, Ana Milagro, Mónica Ariza, Víctor Viñeta, Blanca Fortuño, Concepción López, Miriam Latorre-Millán, Laura Clusa, David Badenas-Alzugaray, Rosa Martínez, Carmen Torres and Antonio Rezusta

Antibiotics 2025, 14(7), 703; https://doi.org/10.3390/antibiotics14070703 - 12 Jul 2025

Abstract

Background/Objectives: Cefiderocol is a novel siderophore cephalosporin with potent in vitro activity against a broad spectrum of Gram-negative bacteria, including carbapenemase-producing Enterobacterales (CPE). However, the recent emergence of resistance in clinical settings raises important concerns regarding its long-term effectiveness. This study aims [...] Read more.

Background/Objectives: Cefiderocol is a novel siderophore cephalosporin with potent in vitro activity against a broad spectrum of Gram-negative bacteria, including carbapenemase-producing Enterobacterales (CPE). However, the recent emergence of resistance in clinical settings raises important concerns regarding its long-term effectiveness. This study aims to investigate the genomic determinants associated with cefiderocol resistance in CPE isolates of human origin. Methods: Comparative genomic analyses were conducted between cefiderocol-susceptible and -resistant CPE isolates recovered from human clinical and epidemiological samples at a tertiary care hospital. Whole-genome sequencing, variant annotation, structural modelling, and pangenome analysis were performed to characterize resistance mechanisms. Results: A total of 59 isolates (29 resistant and 30 susceptible) were analyzed, predominantly comprising Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae. The most frequent carbapenemase gene among the resistant isolates was bla_NDM, which was also present in a subset of susceptible strains. The resistant isolates exhibited a significantly higher burden of non-synonymous mutations in their siderophore receptor genes, notably within fecR, fecA, fiu, and cirA. Structural modelling predicted deleterious effects for mutations such as fecR:G104S and fecA:A190T. Additionally, porin loss and loop 3 insertions (e.g., GD/TD) in OmpK36, as well as OmpK35 truncations, were more frequent in the resistant isolates, particularly in high-risk clones such as ST395 and ST512. Genes associated with toxin–antitoxin systems (chpB2, pemI) and a hypothetical metalloprotease (group_2577) were uniquely found in the resistant group. Conclusions: Cefiderocol resistance in CPE appears to be multifactorial. NDM-type metallo-β-lactamases and missense mutations in siderophore uptake systems—especially in those encoded by fec, fhu, and cir operons—play a central role. These may be further potentiated by alterations in membrane permeability, such as porin disruption and efflux deregulation. The integration of genomic and structural approaches provides valuable insights into emerging resistance mechanisms and may support the development of diagnostic tools and therapeutic strategies. Full article

(This article belongs to the Special Issue Carbapenem-Resistant Enterobacteriaceae: Epidemiology, Detection and Treatment)

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19 pages, 1127 KiB

Open AccessReview

Antibiotic Treatment vs. Non-Antibiotic Treatment in Bovine Clinical Mastitis During Lactation with Mild and Moderate Severity

by Franziska Nankemann, Stefanie Leimbach, Julia Nitz, Anne Tellen, Nicole Wente, Yanchao Zhang, Doris Klocke, Isabel Krebs, Stephanie Müller, Sabrina Teich, Jensine Wilm, Pauline Katthöfer, Jan Kortstegge and Volker Krömker

Antibiotics 2025, 14(7), 702; https://doi.org/10.3390/antibiotics14070702 - 12 Jul 2025

Abstract

Background/Objectives: This review aimed to compare the efficacy of antibiotic treatment vs. non-antibiotic treatment in mild and moderate clinical mastitis in lactating dairy cows, categorized by the causative pathogen. Methods: The initial systematic review plan, which resulted in only four relevant articles, was [...] Read more.

Background/Objectives: This review aimed to compare the efficacy of antibiotic treatment vs. non-antibiotic treatment in mild and moderate clinical mastitis in lactating dairy cows, categorized by the causative pathogen. Methods: The initial systematic review plan, which resulted in only four relevant articles, was altered due to limited available studies and significant heterogeneity among them. Consequently, five additional articles, closely meeting our criteria with minor differences, were included to ensure comprehensive analysis, resulting in nine included articles. Due to these pragmatic constraints, this review represents a hybrid between a systematic and a narrative review. The outcome of interest was the bacteriological cure (BC). Results: The findings revealed that antibiotic treatment resulted in improved BC rates for cases caused by Streptococci. For cases caused by Escherichia (E.) coli, antibiotic therapy showed no significant improvement in BC rates compared to non-antibiotic treatment, suggesting that antibiotics may be often unnecessary for these cases due to self-limiting tendencies. However, severe E. coli mastitis warrants systemic antibiotic treatment due to potentially life-threatening complications. Klebsiella spp. mastitis showed better cure rates with antibiotic therapy. Conclusions: This study underscores the importance of regular pathogen diagnostics to guide appropriate treatment, advocating for the use of on-farm rapid tests to reduce unnecessary antibiotic use while ensuring effective treatment outcomes. Full article

(This article belongs to the Special Issue Evidence in Antibiotic Mastitis Therapy)

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14 pages, 355 KiB

Open AccessArticle

Distribution and Determinants of Antibiotic Self-Medication: A Cross-Sectional Study in Chinese Residents

by Guo Huang, Pu Ge, Mengyun Sui, He Zhu, Sheng Han and Luwen Shi

Antibiotics 2025, 14(7), 701; https://doi.org/10.3390/antibiotics14070701 - 12 Jul 2025

Abstract

Antimicrobial resistance (AMR) represents a critical global health threat, with inappropriate antibiotic self-medication (ASM) being a key contributor. China—as the world’s largest antibiotic consumer—faces significant challenges despite regulatory efforts, compounded by limited contemporary data during the COVID-19 pandemic. A nationwide cross-sectional study was [...] Read more.

Antimicrobial resistance (AMR) represents a critical global health threat, with inappropriate antibiotic self-medication (ASM) being a key contributor. China—as the world’s largest antibiotic consumer—faces significant challenges despite regulatory efforts, compounded by limited contemporary data during the COVID-19 pandemic. A nationwide cross-sectional study was conducted using the 2021 China Family Health Index Survey (n = 11,031 participants across 120 cities). Trained investigators administered face-to-face questionnaires assessing ASM practices, decision-making factors, and sociodemographic characteristics. Multivariate logistic regression identified determinants of ASM. Overall, ASM prevalence was 33.7% (n = 3717), with no urban-rural difference (p > 0.05). Physician advice (78.2%), drug safety (67.1%), and efficacy (64.2%) were primary selection criteria; rural residents prioritized drug price and salesperson recommendations more than their urban counterparts (p < 0.01). Key predictors included higher ASM odds among females (OR = 1.30, 95%CI:1.18–1.43), middle-aged adults (46–59 years; OR = 1.20, 95%CI:1.02–1.42), those with health insurance (resident: OR = 1.33; commercial: OR = 1.62), and individuals with drinking histories (OR = 1.20, 95%CI:1.10–1.31). Lower odds were associated with primary education (OR = 0.69, 95%CI:0.58–0.81), unemployment (OR = 0.88, 95%CI:0.79–0.98), and absence of chronic diseases (OR = 0.56, 95%CI:0.47–0.67). One-third of Chinese residents engaged in ASM during the pandemic, driven by intersecting demographic and behavioral factors. Despite converging urban-rural prevalence rates, distinct decision-making drivers necessitate context-specific interventions, including strengthened pharmacy regulation in rural areas, tailored education programs for high-risk groups, and insurance system reforms to disincentivize self-medication. Full article

(This article belongs to the Special Issue Antibiotic Use in the Communities—2nd Edition)

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