Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (927)

Search Parameters:
Keywords = MDR bacteria

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
17 pages, 1892 KB  
Article
A New Trichlorinated Xanthone and Compounds Isolated from Cladonia skottsbergii with Antimicrobial Properties
by Marvin J. Rositzki, Achara Raksat, Charles J. Simmons, Clifford Smith, Reverend Danette V. Choi, Supakit Wongwiwatthananukit and Leng Chee Chang
Pharmaceuticals 2026, 19(1), 174; https://doi.org/10.3390/ph19010174 - 19 Jan 2026
Abstract
Background/Objectives: The global rise in multidrug-resistant (MDR) bacteria, particularly methicillin-resistant and methicillin-susceptible Staphylococcus aureus (MRSA and MSSA), continues to pose a major public health challenge, including in Hawaii. This underscores the need to discover new antimicrobial agents from natural sources. Guided by [...] Read more.
Background/Objectives: The global rise in multidrug-resistant (MDR) bacteria, particularly methicillin-resistant and methicillin-susceptible Staphylococcus aureus (MRSA and MSSA), continues to pose a major public health challenge, including in Hawaii. This underscores the need to discover new antimicrobial agents from natural sources. Guided by teachings from a Buddhist master regarding the medicinal value of lichens, we investigated the endemic Hawaiian lichen Cladonia skottsbergii. Methods: Specimens of C. skottsbergii were collected from the Lotus Buddhist Monastery in Mountain View, Hawaii. A methanolic extract was prepared and purified using chromatographic techniques, and compound structures were elucidated through spectroscopic analyses and single-crystal X-ray diffraction. The antibacterial activity of the compounds was assessed against Gram-positive strains (MRSA, MSSA) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa). Cytotoxicity was assessed using A549 (non-small cell lung cancer) and Vero E6 (non-tumorigenic) cell lines. Results: Three compounds were isolated: clarosione (1), a newly identified trichlorinated xanthone, and two known metabolites, (S)-usnic acid (2) and perlatolic acid (3). Compounds 2 and 3 demonstrated strong inhibitory effects against MRSA and MSSA. Their minimum inhibitory concentrations (MICs) ranged from 2 to 4 µg/mL, compared with vancomycin (0.5–1 µg/mL). Cytotoxicity testing showed higher sensitivity in A549 cells than in Vero E6 cells, resulting in favorable selectivity indices for the active compounds. Conclusions: In the current study, a new compound, clarosione (1) was discovered. This enhances our understanding of the constituents of C. skottsbergii and its potential antibacterial properties. Lichen-derived compounds may serve as lead candidates for further development, and further study is warranted. Full article
Show Figures

Graphical abstract

16 pages, 279 KB  
Article
Epidemiological and Clinical Characteristics Associated with Antimicrobial-Resistant Urinary Tract Infections in Outpatient and Inpatient Settings: A Retrospective Study from Northwestern Mexico
by Jose Monroy-Higuera, Uriel A. Angulo-Zamudio, Nidia Leon-Sicairos, Hector Flores-Villaseñor, Jorge Velazquez-Roman, Ernesto Ruiz-Trejo, Julio Medina-Serrano, Francisco Castro-Apodaca, Gabriela Tapia-Pastrana and Adrian Canizalez-Roman
Pathogens 2026, 15(1), 92; https://doi.org/10.3390/pathogens15010092 - 14 Jan 2026
Viewed by 201
Abstract
Antimicrobial resistance in urinary tract infections (UTIs) poses a critical public health challenge, yet comparative data between outpatient and inpatient settings remain limited, particularly in Latin America. This study characterized the epidemiology, microbiology, and resistance patterns of UTIs in northwestern Mexico. A retrospective [...] Read more.
Antimicrobial resistance in urinary tract infections (UTIs) poses a critical public health challenge, yet comparative data between outpatient and inpatient settings remain limited, particularly in Latin America. This study characterized the epidemiology, microbiology, and resistance patterns of UTIs in northwestern Mexico. A retrospective analysis of 1041 patients with UTI (May–November 2024) was conducted. Microorganism identification and antimicrobial susceptibility were determined using the MicroScan WalkAway system in accordance with CLSI guidelines. Results: Outpatients accounted for 80.5% of cases and inpatients for 19.4%, with a 3.1% mortality rate. Escherichia coli predominated (62.9%), with a significant association with outpatients (p = 0.02), whereas Enterobacter cloacae, Acinetobacter spp., Candida tropicalis, and C. albicans were associated with inpatients (p < 0.05). Pediatric patients exhibited distinctive microbiological profiles: Pseudomonas aeruginosa (9.7% vs. 2.1%, p = 0.032), Enterococcus faecalis (33.3% vs. 16.2%, p = 0.001), and Staphylococcus epidermidis (26.6% vs. 6.5%, p = 0.027) were significantly more prevalent than in adults. Multidrug resistance (MDR) was detected in 27.1% of isolates, and extensive drug resistance (XDR) in 3.2%. XDR was associated with Gram-positive bacteria (12.2% vs. 1.4%, p < 0.001). Carbapenem-resistant Enterobacteriaceae (CRE) were identified in 0.9% (7/772) of cases, with 42.9% occurring in outpatients. Hospitalization (OR: 2.01; 95% CI: 1.43–2.83), surgical services (OR: 1.41; 95% CI: 1.02–1.97), and recent surgery (OR: 2.37; 95% CI: 1.04–5.39) were independent predictors of MDR/XDR infections. Conclusions: These findings demonstrate the emergence of CRE within the community and distinctive pediatric resistance patterns, underscoring the need for tailored antimicrobial stewardship strategies in this region. Full article
22 pages, 2673 KB  
Article
Epidemiology of Healthcare-Associated Infections Caused by Multidrug-Resistant Bacteria and Antimicrobial Resistance Patterns in a Romanian Tertiary Care Hospital
by Andreea Mihaela Sandu, Corneliu Ovidiu Vrancianu, Ana-Catalina Tantu, Vasilica Mihaela Dumitrache, Daniel Diaconescu, Roxana-Elena Cristian, Andreea Marcu and Monica Marilena Tantu
J. Clin. Med. 2026, 15(2), 667; https://doi.org/10.3390/jcm15020667 - 14 Jan 2026
Viewed by 140
Abstract
Background/Objectives: Healthcare-associated infections (HAIs), particularly those caused by multidrug-resistant (MDR) bacteria, remain a major challenge for Romanian hospitals. This study aimed to evaluate the epidemiological burden of MDR-related HAIs and to characterize the distribution of MDR bacterial isolates and their antimicrobial resistance patterns [...] Read more.
Background/Objectives: Healthcare-associated infections (HAIs), particularly those caused by multidrug-resistant (MDR) bacteria, remain a major challenge for Romanian hospitals. This study aimed to evaluate the epidemiological burden of MDR-related HAIs and to characterize the distribution of MDR bacterial isolates and their antimicrobial resistance patterns over four consecutive semesters in a Romanian tertiary care hospital. Methods: A retrospective study was conducted using data from the Electronic Registry of HAIs, clinical observation sheets, and microbiology laboratory records. An epidemiological analysis was performed on patients diagnosed with MDR-related HAIs, while a separate microbiological analysis included all MDR bacterial isolates identified during the study period. Descriptive and comparative statistical analyses were applied to assess temporal trends, pathogen distribution, and resistance profiles. Results: Of the 327 HAIs identified, 56 cases (17.13%) were caused by MDR bacteria. Most MDR-HAIs originated from the Intensive Care Unit (≈60%), with Acinetobacter baumannii and Klebsiella spp. as the predominant pathogens. Overall mortality among patients with MDR-HAIs was high (51.79%), particularly in infections caused by A. baumannii and K. pneumoniae. Microbiological analysis of MDR isolates (n = 406) revealed consistently high resistance rates to ciprofloxacin, cefepime, and ceftazidime, exceeding 95% in 2023–2024, while resistance to carbapenems surpassed 90% by the end of the study period. Temporal variability in MDR burden was observed across semesters, suggesting an influence of clinical and institutional factors. Conclusions: MDR-related HAIs represent a significant and persistent problem in Romanian acute-care hospitals, particularly in Intensive Care Units. The dominance of carbapenem-resistant A. baumannii and extended-spectrum beta-lactamase-producing and carbapenem-resistant Klebsiella spp. highlights the urgent need for strengthened antimicrobial stewardship, enhanced microbiological surveillance, and reinforced infection prevention strategies. Full article
(This article belongs to the Special Issue Clinical Strategies for Preventing Healthcare-Associated Infections)
Show Figures

Figure 1

28 pages, 2243 KB  
Review
Colistin Resistance in Gram-Negative Bacteria: Mechanisms, Transmission, and Novel Intervention Strategies
by Shah Zeb, Arzoo Nazir, Muhammad Fazal Hameed, Sadia Ikram, Syed Zeeshan Haider Naqvi, Muhammad Shoaib, Patrick Butaye, Zhiqiang Wang, Ruichao Li and Xiaoyu Lu
Microorganisms 2026, 14(1), 173; https://doi.org/10.3390/microorganisms14010173 - 13 Jan 2026
Viewed by 376
Abstract
Multidrug resistance (MDR) in Gram-negative bacteria is a global issue and needs to be addressed urgently. MDR can emerge through genetic mutations and horizontal gene transfer and deteriorate under antibiotic selective pressure. The emergence of resistance to last-resort antibiotics, which are used to [...] Read more.
Multidrug resistance (MDR) in Gram-negative bacteria is a global issue and needs to be addressed urgently. MDR can emerge through genetic mutations and horizontal gene transfer and deteriorate under antibiotic selective pressure. The emergence of resistance to last-resort antibiotics, which are used to treat MDR bacteria, is of particular concern. Colistin has been recognized as a last-line antibiotic for the treatment of MDR Gram-negative bacterial infections caused by Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Recently, the increasing reports of colistin resistance pose a significant threat to public health, caused by both acquired and intrinsic mechanisms. The review aimed to elucidate the trends in colistin resistance, the use of colistin in human and veterinary medicine, underlying resistance mechanisms and transmission pathways, and potential mitigation of this emerging threat through novel intervention strategies. Colistin resistance is mediated by plasmid-encoded phosphoethanolamine transferases (mcr-1 to mcr-10) and chromosomal lipid A remodeling pathways. In Escherichia coli, resistance involves mcr-1–10, acrB efflux mutations, pmrA/pmrB, arnBCADTEF, and mgrB inactivation. Klebsiella pneumoniae exhibits mcr-1, mcr-8, mcr-9, mgrB disruption and phoP/phoQ–pmrAB activation. Acinetobacter baumannii harbors mcr-1–4, while Salmonella enterica and Enterobacter spp. carry mcr variants with arnBCADTEF induction. Therapeutic options include adjunct strategies such as antimicrobial peptides, nanomaterials, therapeutic adjuvants, CRISPR-Cas9-based gene editing, probiotics, vaccines, and immune modulators to restore susceptibility. This review identified that specific and wide actions are required to handle the growing colistin resistance, including genomic surveillance, tracing novel resistance mechanisms, and the application of alternative management strategies. The One Health approach is considered a key strategy to address this growing issue. Full article
(This article belongs to the Special Issue Resistance of Gram-Negative Bacteria to Last-Resort Antibacterials)
Show Figures

Figure 1

14 pages, 680 KB  
Article
Antimicrobial Resistance Profile of Urinary Bacterial Isolates from Hospitalized Companion Dogs Reveals a Potential Public Health Risk in South Korea
by Seoyoon Park, Changseok Han, Su-Man Kim, Joong-Hyun Song and Tae-Hwan Kim
Vet. Sci. 2026, 13(1), 70; https://doi.org/10.3390/vetsci13010070 - 10 Jan 2026
Viewed by 204
Abstract
Emerging antimicrobial resistance (AMR) in companion animals represents a global health concern as they serve as potential reservoirs for multidrug-resistant (MDR) bacteria, which can be transmitted to humans. Herein, we provide comprehensive surveillance data on resistance patterns in veterinary hospital settings, focusing on [...] Read more.
Emerging antimicrobial resistance (AMR) in companion animals represents a global health concern as they serve as potential reservoirs for multidrug-resistant (MDR) bacteria, which can be transmitted to humans. Herein, we provide comprehensive surveillance data on resistance patterns in veterinary hospital settings, focusing on urinary tract infection. A total of 23 bacterial strains were isolated from urine specimens of hospitalized companion animals suspected of urinary tract infections (UTIs) between 2022 and 2024. 16S rRNA sequencing analysis revealed that Escherichia coli (47.8%), Klebsiella pneumoniae (21.7%), and Pseudomonas aeruginosa (8.7%) were predominant uropathogens. Minimum inhibitory concentration and minimum bactericidal concentration tests were employed to analyze AMR patterns across different classes of antibiotics. Moreover, antimicrobial susceptibility test exhibited 73.91% MDR according to the standard definition given by the Clinical and Laboratory Standards Institute (CLSI) M100 guidelines. Most Gram-negative bacteria have been shown to be resistant to beta-lactam antibiotics, especially carbapenems. Notably, an E. coli strain was confirmed to possess the blaNDM-1 gene encoding the carbapenemase New Delhi metallo-β-lactamase. These findings support the implementation of targeted infection control measures and evidence-based treatment protocols to preserve antimicrobial efficacy in companion animal medicine to minimize potential public health risks through the One Health approach. Full article
(This article belongs to the Section Veterinary Microbiology, Parasitology and Immunology)
Show Figures

Figure 1

17 pages, 7081 KB  
Article
Antibacterial Activity of Bacteriophage Lytic Enzyme Ply900
by Yuan Li, Luxiang Xu, Yuhan Zhang, Chunliu Dong and Han Zhou
Vet. Sci. 2026, 13(1), 65; https://doi.org/10.3390/vetsci13010065 - 9 Jan 2026
Viewed by 162
Abstract
S. suis is a prominent zoonotic pathogen responsible for diseases such as arthritis in piglets, swine septicemia, and meningitis. The emergence of multi-drug resistance (MDR) underscores the urgent need for the development of novel antibacterial strategies. In this context, a systematic evaluation of [...] Read more.
S. suis is a prominent zoonotic pathogen responsible for diseases such as arthritis in piglets, swine septicemia, and meningitis. The emergence of multi-drug resistance (MDR) underscores the urgent need for the development of novel antibacterial strategies. In this context, a systematic evaluation of the antibacterial potential of the bacteriophage lytic enzyme Ply900 was conducted in this study, along with an analysis of its domain functions and an in vivo study of its therapeutic dynamics. Ply900 exhibits potent in vitro lytic activity against multiple bacteria, including Streptococcus suis, Streptococcus agalactiae, and Staphylococcus aureus. Notably, it possesses broad biochemical stability, with tolerance to diverse environmental conditions. In a mouse model of S. suis serotype 2 SC19 infection, both the direct Ply900 treatment group and the triple therapy group achieved effective eradication of S. suis, with markedly improved survival rates. The remaining bacteria remained susceptible to Ply900, with no evidence of induced resistance development. Mechanistic analysis revealed that the SH3B domain of Ply900 enhances targeted cleavage efficiency by binding synergistically to peptidoglycan with the CHAP domain, with CYS-34, HIS-59, and ASP-28 serving as key amino acid sites for Ply900’s cleavage activity. Collectively, these findings lay the foundation for the potential dual applications of the lysin Ply900, both in the clinical treatment of S. suis infections and in the prevention and control of these pathogenic bacteria in livestock farming. Full article
(This article belongs to the Section Veterinary Microbiology, Parasitology and Immunology)
Show Figures

Graphical abstract

18 pages, 625 KB  
Article
Antibiotic Resistance Profiles of Commensal and Pathogenic Bacteria Isolated from Wild Boar Carcasses in Campania Region, Southern Italy
by Claire Julie Akwongo, Kurt Houf, Lorena Sollena, Luca Borrelli, Alessandro Fioretti, Nicoletta Murru and Maria Francesca Peruzy
Antibiotics 2026, 15(1), 65; https://doi.org/10.3390/antibiotics15010065 - 7 Jan 2026
Viewed by 213
Abstract
Background/Objectives: Antimicrobial resistance (AMR) in wildlife is an emerging public health concern due to the risk of zoonotic transmission, especially through the food chain, yet data on free-ranging animals remain scarce. This study examined the presence and patterns of AMR among bacteria [...] Read more.
Background/Objectives: Antimicrobial resistance (AMR) in wildlife is an emerging public health concern due to the risk of zoonotic transmission, especially through the food chain, yet data on free-ranging animals remain scarce. This study examined the presence and patterns of AMR among bacteria isolated from hunted wild boars in the Campania region of Italy. Methods: Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) was used to identify bacterial isolates from wild boar meat and carcass swabs to the species level, and the Kirby–Bauer disk diffusion test was applied to screen 205 isolates, spanning 20 bacterial genera, against a panel of clinically relevant antibiotics. Resistance metrics were analyzed at genus and antibiotic levels, and patterns were visualized using a hierarchically clustered heatmap. Results: Resistance was detected in 15 of the 20 genera, with full susceptibility observed in Acinetobacter, Arthrobacter, Glutamicibacter, Leclercia, and Rahnella. Overall, 67.3% (138/205) of the isolates showed resistance to at least one antibiotic, with 33.7% (69/205) classified as multidrug-resistant (MDR). Carbapenems retained the highest activity (≥95% susceptibility) among all genera tested, while amoxicillin/clavulanate (78.4%) and aztreonam (57.4%) exhibited the highest mean resistance. Among potential pathogens, Escherichia coli exhibited an extended-spectrum β-lactamase (ESBL)-like phenotype, with resistance to amoxicillin/clavulanate (67%), aztreonam (54%), and ceftazidime (47%) but preserved carbapenem susceptibility. Staphylococcus spp. showed pronounced resistance to linezolid (57%) and erythromycin (52%), whereas Pseudomonas isolates demonstrated elevated resistance to aztreonam and ceftazidime (57% each). Opportunistic pathogens such as Alcaligenes faecalis and Pantoea agglomerans showed peak resistance to ciprofloxacin and amoxicillin/clavulanate. Pathogens and opportunistic pathogens demonstrated higher mean resistance (>30%) than commensals (≤32%), but the difference in mean and median resistance levels was not statistically significant (Mann–Whitney’s U test, W = 4, p = 0.39). Conclusions: These findings highlight the widespread occurrence of AMR and MDR phenotypes, with clinically significant resistance patterns in wild-boar-associated bacteria, including non-pathogenic strains, highlighting their role in the amplification of AMR. Although the preservation of carbapenem susceptibility underscores their potential as last-line antibiotics, the high resistance to commonly used antibiotics raises concerns for zoonotic transmission. Surveillance of wildlife reservoirs therefore remains critical for integrated AMR control. Full article
Show Figures

Figure 1

12 pages, 255 KB  
Article
Cannabidiol (CBD) and Other Cannabinoids as a Promising Alternative Antibacterial Agent—Pilot Study on Enterococcus faecalis and Enterococcus faecium Clinical Strains
by Zuzanna Kraszewska, Katarzyna Grudlewska-Buda, Kacper Wnuk, Ewa Wałecka-Zacharska, Eugenia Gospodarek-Komkowska and Krzysztof Skowron
Molecules 2026, 31(1), 144; https://doi.org/10.3390/molecules31010144 - 1 Jan 2026
Viewed by 240
Abstract
Gram-positive cocci of the Enterococcus genus, despite their prevalence in the environment and the microbiota of healthy people, have become a serious threat in hospitals as opportunistic pathogens. These bacteria have many virulence factors and intrinsic resistance to existing drugs, which significantly narrows [...] Read more.
Gram-positive cocci of the Enterococcus genus, despite their prevalence in the environment and the microbiota of healthy people, have become a serious threat in hospitals as opportunistic pathogens. These bacteria have many virulence factors and intrinsic resistance to existing drugs, which significantly narrows the group of effective antimicrobials. Due to the spread of Multi-Drug-Resistant (MDR) strains, there is a need to search for new substances as potential antibiotics. Our work aimed to evaluate the antimicrobial effect of commercially available products (five oils containing cannabidiol (CBD) and its derivatives and one 99% CBD product in the form of crystals) on 20 clinical strains of E. faecalis and E. faecium. We determined the Minimal Inhibitory Concentration (MIC) of CBD oils using the microdilution method in Mueller–Hinton broth (MHB). The CBD displayed antibacterial properties against all tested Enterococcus spp. strains (MIC ≤ 1 μg/mL). The higher concentration of CBD resulted in a larger antibacterial effect. The obtained MICs of pure CBD and CBD crystals were statistically lower (W = 97, p < 0.001) for E. feacium than E. faecalis. This work confirms the antibacterial activity of CBD on Enterococcus spp., providing a solid basis for further research that can help identify new therapeutic options and gain a deeper understanding of the CBD mechanism of action. Full article
(This article belongs to the Special Issue Drug Resistance and Antimicrobial Activities of Natural Products)
19 pages, 4399 KB  
Article
Novel Insights on the Synergistic Mechanism of Action Between the Polycationic Peptide Colistin and Cannabidiol Against Gram-Negative Bacteria
by Merlina Corleto, Matías Garavaglia, Melina M. B. Martínez, Melanie Weschenfeller, Santiago Urrea Montes, Martin Aran, Leonardo Pellizza, Diego Faccone and Paulo C. Maffía
Pharmaceutics 2026, 18(1), 51; https://doi.org/10.3390/pharmaceutics18010051 - 30 Dec 2025
Viewed by 615
Abstract
Background/Objectives: Colistin (polymyxin E) has re-emerged as a last-hope treatment against MDR Gram-negative pathogens due to the development of extensively drug-resistant Gram-negative bacteria. Unfortunately, rapid global resistance towards colistin has emerged, which represents a major public health concern. In this context (CBD), [...] Read more.
Background/Objectives: Colistin (polymyxin E) has re-emerged as a last-hope treatment against MDR Gram-negative pathogens due to the development of extensively drug-resistant Gram-negative bacteria. Unfortunately, rapid global resistance towards colistin has emerged, which represents a major public health concern. In this context (CBD), a lipophilic molecule derived from Cannabis sativa, exhibits antimicrobial activity mainly against Gram-positive bacteria but is generally ineffective against Gram-negative species. However, synergistic antibacterial activity between CBD and polymyxin B has been reported. The objective of this work is to analyze the colistin–CBD synergy against clinically relevant Gram-negative isolates displaying diverse mechanisms of colistin resistance and to explore the basis of the possible mechanism of action involved in the first steps of this synergy. Methods: Microbiological assays, minimal inhibitory concentration, cell culture, synergy tests by checker board and time kill, biofilm inhibition evaluation by crystal violet and MTT, SEM (scanning electron microscopy), molecules interaction analysis by nuclear magnetic resonance (NMR). Results: The colistin–CBD combination displayed synergy in colistin resistant Gram-negative bacteria and also disrupted preformed biofilms and killed bacteria within them. Time-kill assays revealed rapid bactericidal activity and SEM showed mild surface alterations on bacterial outer membranes after sublethal colistin monotherapy. Furthermore, a series of sequential treatment assays on colistin-resistant Escherichia coli showed that simultaneous exposure to both compounds was required for activity, as introducing a washing step between treatments abolished the antibacterial effect. In order to obtain deeper insight into this mechanism, NMR analyses were performed, revealing specific molecular interactions between CBD and colistin molecules. Conclusions: These results provide evidence for the first time that both molecules engage through a specific and structurally meaningful interaction and only display synergy when acting together on colistin-resistant bacteria. Full article
(This article belongs to the Section Drug Targeting and Design)
Show Figures

Graphical abstract

18 pages, 2502 KB  
Article
Efficacy of Dual-Antibiotic-Loaded Bone Cement Against Multi-Drug-Resistant Staphylococcus aureus and Enterococcus faecalis in a Galleria mellonella Model of Periprosthetic Joint Infection
by You Zhao, Gopala Krishna Mannala, Raphaëlle Youf, Martina Humez, Ruth Schewior, Klaus-Dieter Kühn, Volker Alt and Martijn Riool
Antibiotics 2025, 14(12), 1280; https://doi.org/10.3390/antibiotics14121280 - 17 Dec 2025
Viewed by 455
Abstract
Background: Antibiotic-loaded bone cement (ALBC) is widely used for local antibiotic delivery in joint arthroplasty to prevent and treat prosthetic joint infections (PJIs). In this study, we evaluated the efficacy of cemented Kirschner (K)-wires coated with various ALBC formulations using a Galleria mellonella [...] Read more.
Background: Antibiotic-loaded bone cement (ALBC) is widely used for local antibiotic delivery in joint arthroplasty to prevent and treat prosthetic joint infections (PJIs). In this study, we evaluated the efficacy of cemented Kirschner (K)-wires coated with various ALBC formulations using a Galleria mellonella infection model against multidrug-resistant (MDR) Staphylococcus aureus and Enterococcus faecalis. Methods: We tested commercially available bone cements, including gentamicin-only formulations (PALACOS R+G) and dual-antibiotic formulations, combining gentamicin with either clindamycin (COPAL G+C) or vancomycin (COPAL G+V), alongside an antibiotic-free control (PALACOS R). In vitro assays—including minimum inhibitory/bactericidal concentration (MIC/MBC) determination, antibiotic release kinetics, agar diffusion, and antibiofilm evaluations—demonstrated effective antibiotic release and significant antimicrobial activity against both planktonic and biofilm-associated bacteria. Results: In vivo, ALBC-coated K-wires were well tolerated in G. mellonella and significantly protected the larvae from S. aureus infection compared to controls. Notably, dual-antibiotic formulations provided superior protection, correlating with substantial reductions in bacterial colonisation on implant surfaces and in surrounding tissues. Conclusions: These findings support the utility of the G. mellonella model as a high-throughput, cost-effective platform for the preclinical evaluation of antimicrobial strategies to prevent and treat PJIs and further demonstrate the effectiveness of dual-loaded ALBC against multidrug-resistant bacteria. Full article
Show Figures

Figure 1

17 pages, 877 KB  
Article
Multidrug Resistance in Bacterial Isolates from Clinical Samples Submitted to a National Veterinary Diagnostic Facility in Uganda (2014–2020): A Retrospective Analysis
by Steven Kakooza, Michael Mahero, Damien F. N. Munyiirwa, Wilfred Eneku, Esther Nabatta, Paul Ssajjakambwe, Grace Athieno, Dorcus Namuyinda, Edrine B. Kayaga, Howard Onyuth, Edward M. Wampande, Francis Mutebi and John B. Kaneene
Antibiotics 2025, 14(12), 1276; https://doi.org/10.3390/antibiotics14121276 - 16 Dec 2025
Viewed by 343
Abstract
Background/Objectives: Antimicrobial Resistance (AMR) is a pressing global animal and public health challenge. There is limited data on AMR prevalence, trends, and drivers in bacterial pathogens from animal sources in Uganda. Thus, this study investigated the occurrence and factors associated with multidrug resistance [...] Read more.
Background/Objectives: Antimicrobial Resistance (AMR) is a pressing global animal and public health challenge. There is limited data on AMR prevalence, trends, and drivers in bacterial pathogens from animal sources in Uganda. Thus, this study investigated the occurrence and factors associated with multidrug resistance (MDR) in bacterial isolates recovered from clinical samples of animals submitted to the national veterinary diagnostic laboratory in Uganda. Methods: A retrospective study analyzed antibiogram data of bacteria from animal samples submitted to the Central Diagnostic Laboratory, Makerere University in Uganda between 2014 and 2020. The cleaned dataset comprised 590 cases with antibiogram data. Statistical analyses were conducted using R software version 4.5.2. Results: Gram-negative bacteria were predominant (74.4%) among the samples from clinical cases. The overall MDR proportion in the general bacteria population was 41.7% over the seven-year period. Among the clinically relevant bacteria, MDR was highest in Escherichia coli (57.2%), followed by Staphylococcus aureus (35.8%) and Salmonella (15.5%). Univariable screening of predictors hypothesized that MDR was influenced by year of case submission, animal host type, and bacterial group (p < 0.05). Multivariable logistic regression showed that isolates submitted in 2019 (vs. 2015) had significantly higher odds of MDR (aOR = 4.21; 95% CI: 1.62–13.14), indicating a marked temporal increase in resistance. Gram-negative bacteria (vs. Gram-positives) were also more likely to exhibit MDR (aOR = 1.62; 95% CI: 1.07–2.48). Conclusions: The high occurrence of MDR in bacterial pathogens from animal clinical submissions revealed the need for improved antimicrobial stewardship and integrated AMR surveillance in Uganda, particularly within the central region from which most diagnostic samples originated. Full article
(This article belongs to the Special Issue Antimicrobial Resistance and Infections in Animals)
Show Figures

Figure 1

41 pages, 2242 KB  
Article
Synthesis and Characterization of Triphenyl Phosphonium-Modified Triterpenoids with Never Reported Antibacterial Effects Against Clinically Relevant Gram-Positive Superbugs
by Dafni Graikioti, Constantinos M. Athanassopoulos, Anna Maria Schito and Silvana Alfei
Pharmaceutics 2025, 17(12), 1614; https://doi.org/10.3390/pharmaceutics17121614 - 16 Dec 2025
Viewed by 462
Abstract
Background: To meet the urgent need for novel antibacterial agents that are active also against worrying superbugs, natural pentacyclic triterpenoids, including totally inactive betulin (BET) and betulinic acid (BA), as well as ursolic acid (UA), active on Gram-positive bacteria, have been chemically [...] Read more.
Background: To meet the urgent need for novel antibacterial agents that are active also against worrying superbugs, natural pentacyclic triterpenoids, including totally inactive betulin (BET) and betulinic acid (BA), as well as ursolic acid (UA), active on Gram-positive bacteria, have been chemically modified, achieving compounds 17. Methods: Triterpenoid derivatives 17 and all synthetic intermediates were characterized by chemometric-assisted FTIR and NMR spectroscopy, as well as by other analytical techniques, which confirmed their structure and high purity. Minimum inhibitory concentration values (MICs) of 17, BET, BA and UA were determined by the broth dilution method, using a selection of Gram-positive and Gram-negative clinically isolated superbugs. Results: Performed experiments evidenced that compounds 47 had potent antibacterial effects against Gram-positive methicillin-resistant Staphylococcus aureus and S. epidermidis (MRSA and MRSE), as well as against vancomycin-resistant Enterococcus faecalis and E. faecium (VRE). The antibacterial effects of 47 were due to the insertion of a triphenyl phosphonium (TPP) group and were higher than those reported so far for other BET, BA and UA derivatives, especially considering the complex pattern of resistance of the isolates used here and their clinical source. Conclusions: For the first time, by inserting TPP, a real activity (MICs 2–16 µg/mL) was conferred to inactive BET and BA (MICs > 1024 and 256 µg/mL). Moreover, the antibacterial effects of UA were improved 16- and 32-fold against MRSE and MRSA (MICs = 2 vs. 32 and 64 μg/mL). Future Perspectives: Based on these very promising microbiologic results, new experiments are currently underway with the best-performing compounds 5 and 7 (MICs = 2 μg/mL) on an enlarged number of Gram-positive isolates, to confirm their MICs. Moreover, investigations about their possible antibiofilm activity, time-killing curves and cytotoxicity on eukaryotic cells will be carried out to define their pharmacological behavior and clinical potential. Full article
Show Figures

Graphical abstract

31 pages, 5359 KB  
Article
Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action
by Yu Zhang, Mengkun Li, Shulei Ji, Liu Cong, Shanshan Mao, Jinyue Wang, Xiao Li, Tao Zhu, Zuobin Zhu and Ying Li
Microorganisms 2025, 13(12), 2848; https://doi.org/10.3390/microorganisms13122848 - 15 Dec 2025
Viewed by 404
Abstract
Human infections caused by pathogenic bacteria remain a major global health concern. Among them, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi are particularly prevalent and associated with significant morbidity and mortality. While antibiotics have long been the cornerstone [...] Read more.
Human infections caused by pathogenic bacteria remain a major global health concern. Among them, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi are particularly prevalent and associated with significant morbidity and mortality. While antibiotics have long been the cornerstone of bacterial infection treatment, the widespread and often inappropriate use of these drugs has led to the emergence of multidrug-resistant (MDR) strains. This escalating resistance crisis underscores the urgent need for alternative therapeutic strategies. Amid the escalating global antimicrobial-resistance crisis, a genome-wide screen of 1800 Saccharomyces cerevisiae knockouts identified a TAD1-deficient mutant whose cell-free supernatant (CFS) rapidly eradicates multidrug-resistant E. coli, S. aureus, K. pneumoniae, and S. typhi in vitro. CFS disrupts pathogenic biofilms, downregulates biofilm-associated genes, and exerts bactericidal activity by triggering intracellular reactive oxygen species (ROS) accumulation and compromising envelope integrity. Probiotic profiling revealed robust tolerance to an acidic pH and physiological bile, high auto-aggregation, and efficient co-aggregation with target pathogens. In both Galleria mellonella and murine infectious models, administration of CFS or live yeast significantly increased survival, attenuated intestinal histopathology, and reduced inflammatory infiltration. These data establish the TAD1-knockout strain and its secreted metabolites as dual-function antimicrobial-probiotic entities, offering a sustainable therapeutic alternative to conventional antibiotics against multidrug-resistant bacterial infections. Full article
(This article belongs to the Section Antimicrobial Agents and Resistance)
Show Figures

Figure 1

19 pages, 1980 KB  
Article
Biosolids as Safe Fertilizers for Soybean and Maize: Enhanced Nutrition Without Antibiotic Residues or Phenotypic Resistance in Grains
by Thiago Nery Menezes, Keite Silva Nogueira, Ruanita Veiga, Raizza Zorman Marques, André Carlos Auler, Leandro Flávio Carneiro, Murilo Duma, Rebert Skalisz and Marcelo Pedrosa Gomes
Antibiotics 2025, 14(12), 1244; https://doi.org/10.3390/antibiotics14121244 - 9 Dec 2025
Viewed by 258
Abstract
Background/Objective: Sewage sludge (biosolids) is increasingly reused as a fertilizer to recycle nutrients and close material cycles; however, concerns persist regarding antibiotics and antimicrobial resistance. This study evaluated the agronomic safety and microbiological integrity of biosolid fertilization in soybean and maize systems, with [...] Read more.
Background/Objective: Sewage sludge (biosolids) is increasingly reused as a fertilizer to recycle nutrients and close material cycles; however, concerns persist regarding antibiotics and antimicrobial resistance. This study evaluated the agronomic safety and microbiological integrity of biosolid fertilization in soybean and maize systems, with particular attention to grain quality and food safety. Methods: Soybean and maize were cultivated in greenhouse microcosms under biosolid or mineral fertilization. Soil, roots, shoots, and grains were analyzed for antibiotic residues using LC–MS/MS and antibiotic-resistant bacteria (ARB) using culture-based assays. Minimum inhibitory concentrations for isolates from grains were compared with clinical breakpoints to verify phenotypic susceptibility. Multivariate analyses (PCA) integrating real-time antibiotic concentrations and updated resistance indicators were performed using centered and scaled data. Results: Fluoroquinolones were the predominant residues introduced by biosolids and exhibited consistent time-dependent declines across all treatments, although low concentrations remained detectable at 90 d in several soil–fertilizer–crop combinations. Tetracyclines, macrolides, and sulfonamides showed similar decreasing trends, with planted soils displaying faster dissipation than bulk control soils. Biosolid fertilization increased shoot biomass by 1.5–2.3-fold and nitrogen, phosphorus, and potassium uptake by 30–60% without impairing soybean nodulation or nitrogenase function. ARB was observed in all soils, including mineral and plant-free controls, indicating a natural background resistome. Ciprofloxacin-resistant isolates were detected in one simple sampling point, and MDR proportions were transient (67%), returning to their background levels by 45–90 days. PCA showed that crop presence, not fertilizer type, was the primary driver of microbial ordination, and that antibiotic concentrations and resistance indicators were only weakly aligned, indicating a limited selective pressure. No antibiotic residues or phenotypically resistant bacteria were detected in the soybean or maize grains. Conclusions: Updated residue, resistance, and multivariate data confirmed that biosolids did not induce, amplify, or transfer antibiotic resistance and maintained complete grain safety. Properly treated biosolids function as safe, agronomically beneficial fertilizers aligned with One Health goals, enhancing crop productivity without compromising food quality or increasing antimicrobial resistance. Full article
Show Figures

Figure 1

14 pages, 1352 KB  
Article
First Detection of Critical Carbapenemase Genes (NDM, OXA-48, VIM) in Avian Campylobacter spp. Isolates in Tunisia: A Zoonotic and Public Health Concern
by Manel Gharbi, Mohammed Abdo Saghir Abbas, Chadlia Hamdi, Safa Hamrouni and Abderrazak Maaroufi
Antibiotics 2025, 14(12), 1236; https://doi.org/10.3390/antibiotics14121236 - 8 Dec 2025
Viewed by 447
Abstract
Background/Objectives: The global emergence of carbapenem resistance is a major public health concern. Campylobacter jejuni and Campylobacter coli, key zoonotic agents causing human campylobacteriosis, are mainly isolated from poultry, their primary host. Their increasing resistance in animals and humans highlights the [...] Read more.
Background/Objectives: The global emergence of carbapenem resistance is a major public health concern. Campylobacter jejuni and Campylobacter coli, key zoonotic agents causing human campylobacteriosis, are mainly isolated from poultry, their primary host. Their increasing resistance in animals and humans highlights the risk of gene transfer. This study investigates the molecular mechanisms of carbapenem resistance in 287 avian Campylobacter spp. isolates from Tunisia within a One Health approach. Methods: Antibiotic susceptibility of 287 carbapenem-resistant isolates, including 147 C. jejuni and 140 C. coli, was determined according to CLSI. All isolates were screened by PCR for genes encoding the most reported carbapenemases, including VIM, IMP, NDM and OXA-48. Eleven multidrug-resistant (MDR)/carbapenem-resistant C. coli isolates were selected to determine their clonal lineage by Multilocus sequence typing (MLST). Results: All isolates were susceptible to imipenem, but resistance to meropenem and ertapenem were observed in 60.71% and 35.71% of C. coli isolates, respectively, versus 13.6% in C. jejuni for each antibiotic. The blaVIM, blaNDM and blaOXA-48 genes were detected in 15, 8, and 19 of the 20 C. jejuni isolates, respectively. However, for C. coli, 53, 12, and 15 isolates harbored blaVIM, blaNDM and blaOXA-48 genes, respectively. The eleven (MDR)/carbapenem-resistant C. coli isolates belonged to a unique ST sequence type ST13450. Conclusions: We report for the first time the emergence of blaVIM, blaNDM, and blaOXA-48 genes in Campylobacter spp. isolates of poultry origin highlighting possible horizontal transfer of these genes to pathogenic Gram-negative bacteria of the poultry’s microbiota. Full article
(This article belongs to the Special Issue Antibiotic Resistance in Bacterial Isolates of Animal Origin)
Show Figures

Figure 1

Back to TopTop