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17 pages, 1793 KB  
Article
ESBL-Producing E. coli in Captive Black Bears: Molecular Characteristics and Risk of Dissemination
by Xin Lei, Mengjie Che, Yuxin Zhou, Shulei Pan, Xue Yang, Siyu Liu, Iram Laghari, Mingyue Wu, Ruilin Han, Xiaoqi Li, Lei Zhou, Guangneng Peng, Haifeng Liu, Ziyao Zhou, Kun Zhang and Zhijun Zhong
Vet. Sci. 2025, 12(11), 1085; https://doi.org/10.3390/vetsci12111085 - 14 Nov 2025
Viewed by 49
Abstract
The emergence and global dissemination of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) represent a major public health concern. However, the characterization and capacity for horizontal gene transfer (HGT) of ESBL-E. coli in captive black bears remain substantially understudied. In [...] Read more.
The emergence and global dissemination of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) represent a major public health concern. However, the characterization and capacity for horizontal gene transfer (HGT) of ESBL-E. coli in captive black bears remain substantially understudied. In the present study, 19 ESBL-E. coli strains were successfully identified (13.38%, 19/142). A total of 11 sequence types (STs) were identified from 19 ESBL-E. coli strains using MLST. This included eight known types (ST10, ST2690, ST208, ST695, ST4160, ST540, ST3865 and ST2792) and three new STs. Antimicrobial susceptibility testing demonstrated that all 19 ESBL-E. coli exhibited high resistance to KZ (100.00%), CRO (78.95%), and CTX (73.68%). Polymerase chain reaction (PCR) screening for 14 β-lactam antibiotic resistance genes (ARGs) and their variants revealed that blaCTX-M was the most prevalent, followed by blaSHV, blaTEM, and blaDHA. Furthermore, eight β-lactamase variants were detected, including five blaCTX-M variants (blaCTX-M-15, blaCTX-M-3, blaCTX-M-14, blaCTX-M-55, and blaCTX-M-27) and one variant each of blaSHV-1, blaTEM-1, and blaDHA-14. Conjugation assays revealed that eight ESBL-E. coli strains were capable of conjugative transfer. Five plasmid types (IncFII, IncW, IncFrepB, IncY, and IncHI1) and three mobile genetic elements (MGEs) (IS26, ISEcp1, and trbC) were identified as co-transferred with blaCTX-M. ESBL-E. coli poses a potential threat to captive black bears and may lead to further transmission. Consequently, the implementation of continuous surveillance and targeted interventions is imperative to prevent the transmission of ESBL-E. coli. Full article
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13 pages, 539 KB  
Article
Genomic and Phenotypic Characterization of Two High-Risk Klebsiella pneumoniae Clones (ST258-blaKPC-2 and ST11-blaNDM-1) from a Greek Tertiary Hospital
by Ilias S. Frydas, Emmanouil Kouklakis, Georgios Meletis, Andigoni Malousi, Maria Anna Kyriazidi, Fani Chatzopoulou, Irini Amargianitaki, Kallirhoe Kalinderi, Maria Mavridou, Stella Mitka, Evangelia Panagiotaki and Maria Chatzidimitriou
Antibiotics 2025, 14(11), 1146; https://doi.org/10.3390/antibiotics14111146 - 12 Nov 2025
Viewed by 209
Abstract
Background/Objectives: Klebsiella pneumoniae ST258 and ST11 are global high-risk antimicrobial-resistant clones known for their virulence and resistance gene dissemination. This study aims to identify these clones in a Greek tertiary hospital and understand their resistance profiles and transmission dynamics. Methods: In [...] Read more.
Background/Objectives: Klebsiella pneumoniae ST258 and ST11 are global high-risk antimicrobial-resistant clones known for their virulence and resistance gene dissemination. This study aims to identify these clones in a Greek tertiary hospital and understand their resistance profiles and transmission dynamics. Methods: In January 2025, we isolated two distinct carbapenem-resistant K. pneumoniae in a Greek tertiary hospital: INT18S from an ICU patient’s bronchioalveolar lavage and INT20U from a urine sample in the emergency unit. Antimicrobial susceptibility testing (via Microscan system) and Whole-Genome Sequencing (WGS) were conducted on both isolates and their genomes were submitted to the NCBI. Results: The INT18S isolate carried the blaKPC-2 gene and belonged to the ST258 clone. The INT20U isolate carried the blaNDM-1 gene and belonged to the ST11 clone lineage. Both isolates contained at least one of the extended spectra β-lactamase genes tested (TEM, SHV, OXA-1 and CTX-M group). Conclusions: The co-existence of the high-risk K. pneumoniae clones ST258 and ST11 in different hospital departments increases the risk of resistance gene transfer and suggests potential intra-hospital transmission pathways. Understanding their resistance profiles is critical for guiding treatment strategies and preventing the spread of multidrug-resistant pathogens. Full article
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19 pages, 823 KB  
Article
Antimicrobial Resistance Phenotypes and Genotypes of Escherichia coli Isolates from Artisanal Minas Frescal Cheeses from the Federal District, Brazil
by Letícia Fernandes Silva Rodrigues, Rodrigo Araújo de Melo, Nathalia Mateus Borges, Anna Cléa Silva Aragão, Marta Oliveira de Araújo, Rebeca Dias dos Santos, Carla Azevedo Bilac, Karolina Oliveira Gomes, Bruno Alcântara do Prado, Lívia Cristina Lira de Sá Barreto, Izabel Cristina Rodrigues da Silva and Daniela Castilho Orsi
Antibiotics 2025, 14(11), 1101; https://doi.org/10.3390/antibiotics14111101 - 2 Nov 2025
Viewed by 370
Abstract
Background/Objectives: This study characterized the phenotypic and genotypic profiles of antimicrobial resistance in 104 Escherichia coli isolates obtained from 22 samples of artisanal Minas Frescal cheese from the Federal District, Brazil. Methods: The antimicrobial susceptibility of E. coli isolates was assessed using [...] Read more.
Background/Objectives: This study characterized the phenotypic and genotypic profiles of antimicrobial resistance in 104 Escherichia coli isolates obtained from 22 samples of artisanal Minas Frescal cheese from the Federal District, Brazil. Methods: The antimicrobial susceptibility of E. coli isolates was assessed using the disk diffusion method and antimicrobial resistance genes were detected using polymerase chain reaction methods with specific primers. Results: The highest rates of phenotypic antimicrobial resistance were observed for sulfonamides (85.58%, 89/104) and tetracyclines (38.46%, 40/104). In the genotypic profiles, most E. coli isolates carried the sulfonamide resistance genes sul1/sul2 (62.50%, 65/104), tetracycline resistance genes tetA/tetB (65.38%, 68/104), and β-lactam resistance genes blaCTX-M/blaTEM/blaSHV (55.77%, 58/104). Most E. coli strains that presented sulfonamide resistance genes carried the sul1 gene (49.04%, 51/104) and were phenotypically sulfonamide-resistant strains (59.61%, 62/104). Regarding the E. coli strains that carried tetracycline resistance genes, the majority harbored both tetA and tetB genes (34.61%, 36/104), with 35.56% (37/104) being phenotypically resistant and 29.80% (31/104) being phenotypically susceptible. For E. coli strains that presented β-lactam resistance genes, the most frequently detected gene was blaCTX-M (21.15%, 22/104) and, notably, most E. coli strains (43.26%, 45/104) were phenotypically susceptible. The cat1 and clmA genes (associated with phenicol resistance) were detected in 22.12% of the E. coli isolates (23/104), with only two strains (1.92%) being phenotypically resistant to chloramphenicol. Conclusion: The high prevalence of E. coli carrying antimicrobial resistance genes in artisanal cheese raises public health concerns regarding the dissemination of potentially pathogenic antimicrobial-resistant microorganisms through the food chain. Full article
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18 pages, 1715 KB  
Article
Characterization of Carbapenem-Resistant and ESBL-Producing Enterobacterales in Wastewater and Sludge Environments from Northern Spain
by Mario Sergio Pino-Hurtado, Rosa Fernández-Fernández, Laura Rubio-Tomás, Irene Marañón-Clemente, Tamara Álvarez-Gómez, Diego José García-Mora, Carmen Lozano, Carmen Torres and Myriam Zarazaga
Appl. Sci. 2025, 15(21), 11703; https://doi.org/10.3390/app152111703 - 1 Nov 2025
Viewed by 388
Abstract
Wastewater treatment plants (WWTPs) are recognized hotspots for the convergence and dissemination of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) into the environment. Among ARB, carbapenem-resistant Enterobacterales (CR-E) and extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-Ec/Kp) are of particular concern due [...] Read more.
Wastewater treatment plants (WWTPs) are recognized hotspots for the convergence and dissemination of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) into the environment. Among ARB, carbapenem-resistant Enterobacterales (CR-E) and extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-Ec/Kp) are of particular concern due to their clinical relevance. We characterized 30 CR-E and 176 ESBL-Ec/Kp isolates (two of them were both ESBL-producing and carbapenem-resistant) recovered from influent, intermediate, effluent, sludge, and downstream river samples collected from two WWTPs in northern Spain. Isolates were evaluated for resistance phenotypes against 12 antimicrobials, and β-lactamase-encoding genes were assessed by PCR and sequencing. Notably, among CR-E isolates, blaKPC-2 was the most prevalent (93%), followed by blaOXA-48-like, detected in two isolates from non-treated and pasteurized sludge; both isolates also carried blaCTX-M-15, a finding not previously reported specifically in sludge samples. Among ESBL-Ec/Kp, a broad diversity of ESBL genes was identified, including blaCTX-M group 1 (variants 1, 3, 15, 32, 55), blaCTX-M group 9 (variants 14, 27, 65, 97), blaSHV-12 and blaTEM-169. The most prevalent ESBL gene was blaCTX-M-15 (48.3%), followed by blaCTX-M-14, blaCTX-M-32, and blaSHV-12, detected in 10.8%, 8.5%, and 6.8% of isolates, respectively. CR-E and ESBL-Ec/Kp were found in all sample types and were still detectable at terminal stages, indicating persistence throughout treatment. These findings support the need to improve and optimize current wastewater treatment methods and underscore the importance of integrating culture-based and molecular methods into routine WWTP monitoring for early detection of microbiological hazards, although further research is still needed. Full article
(This article belongs to the Section Applied Microbiology)
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14 pages, 1440 KB  
Article
Co-Occurrence and Molecular Characterization of ESBL-Producing and Colistin-Resistant Escherichia coli Isolates from Retail Raw Meat
by Arife Ezgi Telli, Nihat Telli, Yusuf Biçer, Gamze Turkal, Tahir Yılmaz and Gürkan Uçar
Foods 2025, 14(20), 3573; https://doi.org/10.3390/foods14203573 - 21 Oct 2025
Viewed by 557
Abstract
Background: The emergence of extended-spectrum β-lactamase (ESBL) producing and colistin-resistant Escherichia coli in retail meat poses a significant public health risk. Method: A total of 180 retail meat samples (chicken parts, internals, processed products; lamb; beef; fish) were purchased from markets and butcher [...] Read more.
Background: The emergence of extended-spectrum β-lactamase (ESBL) producing and colistin-resistant Escherichia coli in retail meat poses a significant public health risk. Method: A total of 180 retail meat samples (chicken parts, internals, processed products; lamb; beef; fish) were purchased from markets and butcher shops across Turkiye. Presumptive ESBL-producing isolates were screened on chromogenic agar and phenotypically confirmed. Species identity was verified by uspA PCR, and resistance genes (blaCTX-M, blaTEM, blaOXA, blaSHV, mcr-1, mcr-2, mcr-3) were analyzed. Colistin MICs were determined by broth microdilution, while antimicrobial susceptibility of ESBL-positive isolates was assessed by disk diffusion. Results: Overall, ESBL-producing E. coli were detected in 21.7% (n = 39) of the 180 meat samples analyzed, with the highest prevalence observed in chicken parts (26/40, 65.0%) and giblets (6/10, 60%). All ESBL-E. coli isolates harbored blaCTX-M, with blaCTX-M-1 identified as the sole variant. The blaTEM gene was detected in 61.5% (24/39) of ESBL-positive E. coli isolates. Colistin resistance was identified in six isolates (15.4%), all of which carried the mcr-1 gene. Additionally, one lamb minced meat isolate harbored the mcr-2 gene. Co-occurrence analysis revealed that the most frequent resistance gene combination among ESBL-producing isolates was blaCTX-M1 + blaTEM, detected predominantly in chicken meat samples, while mcr-1 was observed only in isolates harboring single or limited resistance genes, suggesting a distinct acquisition pattern. Conclusions: A high prevalence of blaCTX-M-1 and the co-occurrence of mcr genes were detected in E. coli isolates from retail meat, particularly poultry. The detection of mcr-1/mcr-2 co-carriage in lamb meat, though rare, highlights the need for broader surveillance. These findings underscore the need for integrated monitoring and prudent antimicrobial use in food animals. The use of antibiotics as growth promoters is prohibited in Türkiye, and therapeutic applications require a veterinary prescription; however, stronger enforcement remains essential to limit the dissemination of multidrug-resistant bacteria in the food chain. Full article
(This article belongs to the Section Food Microbiology)
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15 pages, 421 KB  
Article
Occurrence and Molecular Characterization of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli in Broilers in Indonesia
by Nur Hidayatullah, Imron Suandy, Montira Intanon, Thomas Alter, Oli Susanti, Ajeng Herpianti, Sani Susanty, Riska Desitania and Nattakarn Awaiwanont
Antibiotics 2025, 14(10), 1030; https://doi.org/10.3390/antibiotics14101030 - 15 Oct 2025
Viewed by 594
Abstract
Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) are widespread in the food chain, but nationwide surveillance in Indonesian broiler production is limited. This study investigated the occurrence, antimicrobial resistance, phylogenetic diversity, and molecular characteristics of ESBL-E. coli from broilers in Indonesia. [...] Read more.
Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) are widespread in the food chain, but nationwide surveillance in Indonesian broiler production is limited. This study investigated the occurrence, antimicrobial resistance, phylogenetic diversity, and molecular characteristics of ESBL-E. coli from broilers in Indonesia. A total of 2182 E. coli isolates from broiler cecal samples across three regions during the period 2018–2020 were analyzed. Antimicrobial susceptibility testing and ESBL phenotyping were performed following the CLSI guidelines. ESBL resistance genes and phylogenetic groups were detected using multiplex/quadruplex PCR. ESBL-E. coli (9.9%) was most frequently observed in the western (15.2%) region, followed by the central (8.0%) and eastern (7.2%) regions. A total of 85 resistance patterns were identified, with 98.5% exhibiting multidrug resistance. The blaCTX-M gene was detected in 97.5% of isolates, predominantly blaCTX-M-1 (97.5%), while blaCTX-M-9 was found in 2.5%. The blaTEM gene was present in 33.0% of ESBL isolates; however, blaSHV and blaOXA-1 were absent. Phylogenetic group A predominated (42.0%), followed by E (22.5%), B1 (20.5%), F (10.5%), C (2.5%), and D (2.0%). This study demonstrates a significant occurrence of ESBL-E. coli in Indonesian broilers with regional variation and blaCTX-M predominance. The high rate of multidrug resistance poses a serious public health concern, emphasizing the urgent need for antimicrobial stewardship and enhanced surveillance programs. Full article
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12 pages, 1225 KB  
Article
Resensitizing the Untreatable: Zidovudine and Polymyxin Combinations to Combat Pan-Drug-Resistant Klebsiella pneumoniae
by Jan Naseer Kaur, Jack F. Klem, Gebremedhin S. Hailu, Nader N. Nasief, Yang Liu, Allison Hanna, Albert Chen, Patricia Holden, Shivali Kapoor, Nicholas M. Smith, Mark Sutton, Jian Li and Brian T. Tsuji
Pharmaceuticals 2025, 18(10), 1531; https://doi.org/10.3390/ph18101531 - 11 Oct 2025
Viewed by 825
Abstract
Background: The emergence of pan-drug-resistant (PDR) Klebsiella pneumoniae has compromised the efficacy of last-line agents, leaving few therapeutic options. Repurposing zidovudine, an FDA-approved thymidine analog with antibacterial activity, may enhance existing therapies, but pharmacodynamic data under clinically relevant conditions are scarce. This study [...] Read more.
Background: The emergence of pan-drug-resistant (PDR) Klebsiella pneumoniae has compromised the efficacy of last-line agents, leaving few therapeutic options. Repurposing zidovudine, an FDA-approved thymidine analog with antibacterial activity, may enhance existing therapies, but pharmacodynamic data under clinically relevant conditions are scarce. This study addresses this gap using static and dynamic in vitro models. Materials/methods: A PDR strain of Klebsiella pneumoniae harboring blaNDM-1blaCMY-6, blaCTX-M-15, blaSHV-2, and disrupted mgrB was used in this study. Minimum inhibitory concentrations (MICs) followed by static time-kills were performed to investigate the synergistic interplay between zidovudine and last-line antibiotics (ceftazidime/avibactam, polymyxin B). To simulate human pharmacokinetics, a hollow-fiber infection model (HFIM) was employed using steady-state concentrations of zidovudine (4 mg/L), polymyxin B (4 mg/L), and avibactam (22 mg/L). Structural and morphological effects on bacterial cells were examined via fluorescence microscopy following glutaraldehyde fixation. Results: In this study, the PDR K. pneumoniae showed a ~5-fold reduction in polymyxin MIC when combined with zidovudine (from >4 µg/mL to 0.25 µg/mL). Time-kill assays demonstrated ≥2.5 log10 CFU/mL bacterial reduction with zidovudine-based combinations, whereas monotherapies failed to inhibit bacterial growth. In the HFIM, the triple combination achieved rapid bactericidal activity (>3 log10 CFU/mL reduction within 4 h) and sustained killing (>5–6 log10 reduction maintained through 216 h), with bacterial counts remaining below 1 CFU/mL. In contrast, dual combinations initially reduced bacterial burden (1–3 log10 reduction) but failed to maintain suppression, with significant regrowth (>1010 CFU/mL) observed by 168 h. Microscopy corroborated these findings, revealing extensive cellular damage in the zidovudine-containing treatment arms. These HFIM results underscore the potential of zidovudine-based triple therapy in overcoming resistance to last-line antibiotics in K. pneumoniae. Conclusions: Our results provide promising unprecedented insight into novel zidovudine-based combination therapies against difficult-to-treat MBL Gram-negatives. The observed synergy in MIC reduction, rapid killing in time-kill assays, and near-complete eradication in the HFIM underscore the therapeutic potential of this triple combination. Future studies will focus on broadening the application of these novel combinations to other ‘superbugs’, such as highly resistant strains of Acinetobacter baumannii and Pseudomonas aeruginosa. Full article
(This article belongs to the Section Pharmacology)
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18 pages, 1779 KB  
Article
Genomic Characterization of a Rare K30-ST198 Hypervirulent Klebsiella pneumoniae Clone with Distinctive Virulence Features
by Domingo Fernández Vecilla, Jorge Rodríguez Grande, Nuria Fraile Valcárcel, Mary Paz Roche Matheus, Gotzon Iglesias Hidalgo, Cristina Aspichueta Vivanco, José Luis Díaz de Tuesta del Arco, Sergio García-Fernández, María Siller Ruiz, Zaira Moure, Daniela Vallejo Iriarte, Athanasia Varsaki, Jorge Calvo Montes, María Pía Roiz Mesones, María Carmen Fariñas and Alain A. Ocampo-Sosa
Int. J. Mol. Sci. 2025, 26(19), 9601; https://doi.org/10.3390/ijms26199601 - 1 Oct 2025
Viewed by 651
Abstract
Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a significant public health concern, yet rare sublineages remain poorly characterized. Here, we described a K30-ST198 hvKp sublineage identified in four isolates from two patients, including three sequential strains (K30B1, K30B2, K30B3) recovered over eight months [...] Read more.
Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a significant public health concern, yet rare sublineages remain poorly characterized. Here, we described a K30-ST198 hvKp sublineage identified in four isolates from two patients, including three sequential strains (K30B1, K30B2, K30B3) recovered over eight months from recurrent liver abscesses and one strain (K30-HUMV1) from a urinary tract infection. All isolates exhibited a yYpermucoviscous phenotype and resistance restricted to ampicillin and amoxicillin. Screening with the eazyplex hvKp assay detected ybt and rmpA in all strains, yielding a virulence score of 1. Biofilm production was strong in K30B1, K30B2, moderate in K30-HUMV1, but weak in K30B3. In the Galleria mellonella infection model, K30B1 showed higher virulence than the other isolates. Whole-genome sequencing identified the ICEKp1 carrying hypervirulence-associated genes (ybt, pagO, rmpAC, iroBCDN) together with additional virulence factors (fim, mrkD, uge, ureA, wabG, wcaJ, mliC), while antibiotic resistance genes were limited to fosA and blaSHV-77. Protein structures and their functional domains were predicted using AlphaFold v3.0.1 and ColabFold v1.5.5, based on pLDDT scores, providing further insights into gene functionality. This work represents one of the first detailed characterizations of K30-ST198 hvKp, underscoring the need for integrated genomic, phenotypic, and structural approaches in hvKp surveillance. Full article
(This article belongs to the Collection Microbial Virulence Factors)
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22 pages, 3026 KB  
Article
One Health Monitoring of Resistant Pseudomonas aeruginosa in Aquatic, Poultry, and Human Sources: Virulence Traits and blaSHV Gene Tracking
by Ali Wahdan, Mahmoud Ezzat, Amal Emam, Walaa A. Husseiny, Mohamed Abou El-Atta, Ehab M. Abd-Allah, Ahmed M. A. Meligy, Sherief M. Abdel-Raheem, Faisal Almathen, Salah Al-Shami, Saad I. Al-Sultan, Ahmed Alfifi, Wael El-Deeb and Marwa E. Abo Hashem
Pathogens 2025, 14(10), 983; https://doi.org/10.3390/pathogens14100983 - 28 Sep 2025
Viewed by 712
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen of public health concern. This study aimed to investigate the prevalence of P. aeruginosa, some virulence factors, and antimicrobial resistance patterns and highlight the potential pathways of horizontal blaSHV-resistant gene transfer from diverse sources. [...] Read more.
Pseudomonas aeruginosa is an opportunistic pathogen of public health concern. This study aimed to investigate the prevalence of P. aeruginosa, some virulence factors, and antimicrobial resistance patterns and highlight the potential pathways of horizontal blaSHV-resistant gene transfer from diverse sources. A total of 220 samples were collected from fish (n = 90), water (n = 30), poultry (n = 50), and humans (n = 50). All samples were isolated, confirmed by the Vitek 2 system, and tested against antimicrobial agents. Some virulence and resistance genes were examined by PCR and sequenced for the blaSHV-resistant gene from four selected isolates from each source. SPSS v26, with chi-squared tests and Pearson correlations (p < 0.05), was implemented for statistical investigation. P. aeruginosa was isolated at 33.3%, 20%, 14%, and 24% from fish, water, poultry, and humans, respectively. Using the diffusion disk method, extensively drug-resistant (XDR) and multidrug-resistant (MDR) strains were detected. All strains harbored the oprL and toxA genes, while the lasB gene was present in 40% of fish samples but not present in human samples. All strains lacked the exoS gene. The tetA, sul1, blaSHV, and blaTEM resistance genes were detected at different percentages. The blaSHV genes from fish and water isolates were closely related to each other and showed similarity to those of the human isolates. The poultry isolates formed a separate phylogenetic lineage. The emergence of XDR and MDR P. aeruginosa highlights a possible public health threat. Based on the gene similarity between fish and water isolates, our results suggest that these isolates have a common origin. The similarity between the human isolates and environmental isolates (fish and water) raises concerns about possible transmission to humans. Full article
(This article belongs to the Section Bacterial Pathogens)
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17 pages, 818 KB  
Article
Phenotypic and Molecular Study of Multidrug-Resistant Escherichia coli Isolates Expressing Diverse Resistance and Virulence Genes from Broilers in Tunisia
by Ghassan Tayh, Fatma Nsibi, Khaled Abdallah, Omar Abbes, Ismail Fliss and Lilia Messadi
Antibiotics 2025, 14(9), 931; https://doi.org/10.3390/antibiotics14090931 - 15 Sep 2025
Viewed by 1693
Abstract
This study investigated the molecular and phenotypic characteristics of antimicrobial resistance in Escherichia coli isolates recovered from the ceca of healthy broilers in Tunisia. A total of 111 E. coli isolates were obtained from chicken samples collected at slaughterhouses and cultured on cefotaxime-supplemented [...] Read more.
This study investigated the molecular and phenotypic characteristics of antimicrobial resistance in Escherichia coli isolates recovered from the ceca of healthy broilers in Tunisia. A total of 111 E. coli isolates were obtained from chicken samples collected at slaughterhouses and cultured on cefotaxime-supplemented MacConkey agar. All isolates exhibited a multidrug-resistant (MDR) phenotype, and 72.1% were confirmed as extended-spectrum β-lactamase (ESBL) producers. The most frequent β-lactamase gene was blaCTX-M-G1, followed by blaTEM and blaSHV. Carbapenem resistance genes (blaOXA-48 and blaIMP) were detected in 12.6% and 6.3% of isolates, respectively, while six isolates harbored the colistin resistance gene mcr-1. Among the tested virulence genes, fimH, traT, and iutA were the most prevalent, detected in over 70% of isolates. Class 1 integrons were present in 83% of isolates, and class 2 integrons in 39.6%, with gene cassettes encoding resistance to trimethoprim (dfrA) and streptomycin (aadA). These findings highlight the widespread presence of MDR and ESBL-producing E. coli strains with virulence traits and integrons in poultry, underscoring the risk of transmission to humans. This study provides essential data supporting the implementation of integrated surveillance strategies in line with the One Health approach. Full article
(This article belongs to the Special Issue The Antimicrobial Resistance in the Food Chain)
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9 pages, 255 KB  
Article
Presence of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Avian Species in a Petting Zoological Garden
by Juan Casas-Paul, José Luis Bravo-Ramos, María Guadalupe Sánchez-Otero, Sokani Sánchez-Montes, Sashenka Bonilla-Rojas, Luis Arturo Ortíz-Carbajal, Gerardo Gabriel Ballados-González, Jannete Gamboa-Prieto, Alejandra Chong-Guzmán and Angelica Olivares Muñoz
J. Zool. Bot. Gard. 2025, 6(3), 42; https://doi.org/10.3390/jzbg6030042 - 19 Aug 2025
Viewed by 746
Abstract
Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae pose a significant public health risk. As zoos grow in popularity, exotic animals come into closer contact with humans, making them potential reservoirs of ESBLs. However, data on ESBL presence in Mexican zoos remains limited. For this reason, this [...] Read more.
Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae pose a significant public health risk. As zoos grow in popularity, exotic animals come into closer contact with humans, making them potential reservoirs of ESBLs. However, data on ESBL presence in Mexican zoos remains limited. For this reason, this study aimed to isolate and assess the antimicrobial susceptibility of Enterobacteriaceae that colonize avian species in a petting zoo and to identify any ESBL-producing isolates. Cloacal swabs were collected from 34 healthy birds at Miguel Angel de Quevedo Zoo, Veracruz, Mexico. Samples were analyzed microbiologically and molecularly to detect ESBL-encoding genes. A total of seventeen E. coli and one K. pneumoniae strains were isolated from cloacal swabs of bird species, and multidrug resistance (MDR) was found. The most frequently detected genes were blaCTX-M-1 (16/18) and blaTEM-1 (12/18). The detection of multidrug-resistant (MDR) strains carrying blaCTX-M-1, blaTEM-1, and blaSHV genes highlights the potential role of birds as reservoirs and disseminators of antimicrobial resistance (AMR) in urban environments. To the best of our knowledge, this is the first study conducted in Mexico. In conclusion, MDR ESBL-producing bacteria were found in the fecal microbiota of bird species at a petting zoo in Mexico. The limitations of this study emphasize the need for a One Health approach to analyze the genome-wide isolates and epidemiology of antimicrobial-resistant bacteria in captive zoo animals in Mexico. This would support targeted surveillance efforts and help reduce the emergence and spread of resistant bacteria among zoo animals and visitors. Full article
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15 pages, 1048 KB  
Article
Genomic Characterization of Multidrug-Resistant and ESBL-Producing Klebsiella pneumoniae Isolated from Healthy Rabbits Intended for Human Consumption
by Vanessa Silva, Manuela Caniça, Rani Rivière, Adriana Silva, Patrícia Poeta and Gilberto Igrejas
Microorganisms 2025, 13(8), 1931; https://doi.org/10.3390/microorganisms13081931 - 18 Aug 2025
Viewed by 890
Abstract
Klebsiella pneumoniae is an important pathogen associated with multidrug resistance and virulence in both human and animal populations. While its prevalence and resistance patterns are well documented in clinical settings, data on K. pneumoniae in food-producing animals remain scarce. This study aimed to [...] Read more.
Klebsiella pneumoniae is an important pathogen associated with multidrug resistance and virulence in both human and animal populations. While its prevalence and resistance patterns are well documented in clinical settings, data on K. pneumoniae in food-producing animals remain scarce. This study aimed to isolate and characterize multidrug-resistant K. pneumoniae strains from healthy rabbits raised for human consumption, with a focus on antimicrobial resistance genes, plasmid content, and associated mobile genetic elements. A total of 295 fecal samples were collected from rabbits across 20 commercial farms in northern Portugal. Isolates were confirmed using MALDI-TOF MS, tested for hypermucoviscosity, and subjected to antimicrobial susceptibility testing (EUCAST). Whole-genome sequencing (WGS) was performed to determine sequence types (STs), resistance genes, plasmids, and resistance determinants for metals and biocides. Six K. pneumoniae isolates were recovered, showing extensive antimicrobial resistance profiles, including ESBL genes such as blaCTX-M-15, blaSHV-28, and blaTEM-1. The most frequent ST was ST307. Multiple genes resistant to heavy metals were identified. Plasmid analysis revealed the presence of IncFII, IncN, and ColRNAI types. Network analysis showed clusters of genetically related isolates and highlighted shared resistance mechanisms. The presence of multidrug-resistant K. pneumoniae in healthy rabbits destined for human consumption underscores the zoonotic potential of this species and the need for surveillance in the animal–food–human interface. These findings contribute to a better understanding of resistance ecology in the context of One Health. Full article
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19 pages, 2657 KB  
Article
Molecular Surveillance of ESBL and Carbapenemase Genes in Gram-Negative Bacterial Pathogens Isolated from Various Clinical Samples Collected from Northern Region of United Arab Emirates
by Premalatha Ragupathi, Vaneezeh Khamisani, Aisha Fadila Sadiq, Mariam Aliyu Mobiddo, Nasir Parwaiz, Sovan Bagchi and Nazeerullah Rahamathullah
Microorganisms 2025, 13(8), 1880; https://doi.org/10.3390/microorganisms13081880 - 12 Aug 2025
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Abstract
The aim of this study was to explore the prevalence of ESBL and carbapenemase genes in Gram-negative bacteria isolated from various clinical samples collected from northern regions of UAE. In total 3670 clinical samples were obtained from patients attending various hospitals and clinics [...] Read more.
The aim of this study was to explore the prevalence of ESBL and carbapenemase genes in Gram-negative bacteria isolated from various clinical samples collected from northern regions of UAE. In total 3670 clinical samples were obtained from patients attending various hospitals and clinics in the northern regions of the UAE. All the samples underwent routine bacterial culture examination, and their antibiotic sensitivity patterns mainly on beta-lactam and carbapenem resistance in Gram-negative bacteria. Molecular detection of ESBL and carbapenemase genes (blaCTX-M, blaTEM, blaSHV, blaNDM, blaIMP, and blaOXA-48) was performed on them. A total of 249 MDR Gram-negative bacteria (E. coli, K. pneumoniae, P. aeruginosa, P. mirabilis and A. baumannii) were isolated. The genes blaCTX-M, blaTEM, and blaSHV were detected in all the MDR isolates. Among them, the blaCTX-M was predominant especially in E. coli. The blaNDM and blaIMP were detected in a few K. pneumoniae and A. baumannii. The genes combination blaCTX-M+TEM and blaCTX-M+SHV, blaCTX-M+SHV, blaTEM+SHV, and blaTEM+NDM were detected mostly in K. pneumoniae and E. coli, and few A. baumannii. The gene combination blaCTX-M+TEM+SHV and blaCTX-M+TEM+SHV+IMP were also detected in few E. coli, P. aeruginosa, and A. baumannii. The current findings highlight the importance of molecular detection of ESBL and carbapenemase genes to emphasize monitoring and controlling the development of MDR bacterial pathogens. Full article
(This article belongs to the Special Issue Evolution and Spread of Drug-Resistant Pathogens)
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23 pages, 1347 KB  
Article
Antibiotic Resistance, Virulence Genes, and Molecular Diversity of Clinical Klebsiella pneumoniae Isolates from Patients of District Hospital in Central Poland
by Barbara Kot, Małgorzata Witeska, Piotr Szweda, Małgorzata Piechota, Elżbieta Kondera, Elżbieta Horoszewicz, Izabela Balak, Ahmer Bin Hafeez and Alicja Synowiec
Pathogens 2025, 14(7), 648; https://doi.org/10.3390/pathogens14070648 - 30 Jun 2025
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Abstract
In hospital environments, pathogenic bacteria spread easily and acquire virulence and antibiotic resistance genes. The aim of the study was an evaluation of the genetic diversity of 109 K. pneumoniae isolates recovered from patients of a district hospital in central Poland. The frequencies [...] Read more.
In hospital environments, pathogenic bacteria spread easily and acquire virulence and antibiotic resistance genes. The aim of the study was an evaluation of the genetic diversity of 109 K. pneumoniae isolates recovered from patients of a district hospital in central Poland. The frequencies of genes coding for β-lactamases, efflux pumps, and virulence factors were determined. Genotyping of the isolates was performed with ERIC (Enterobacterial Repetitive Intergenic Consensus) and REP (Repetitive Element Sequence Based) PCR techniques, with 21 and 19 genotypes being identified, respectively. The blaSHV-1 (92.7%), blaCTX-M group 1 (83.5%), blaTEM-1 (28.4%), blaNDM-1 (16.5%), blaVEB-1 (11.0%), blaCTX-M group 9 (3.7%), blaKPC (1.8%), blaIMP, blaOXA-48, blaCTX-M group 2, blaCTX-M groups 8, and 25/26 (0% each) and efflux pumps: AcrAB (100%), tolC (93.6%), and mdtk (60.5%), and virulence genes coding: urease subunit ureA (94.5%) endotoxins wabG (92.7%) and uge (64.2%), and siderophore iucB (3.7%) were detected. The blaSHV-1, blaCTX-M group 1, mdtk, tolC, AcrAB (16.5%); blaSHV-1, blaCTX-M group 1, tolC, AcrAB (15.6%), and blaSHV-1, blaCTX-M group 1, blaNDM-1, mdtk, tolC, AcrAB (11.9%) were the most common resistance patterns. The distribution of resistance and virulence genes varied more between hospital wards than between different clinical materials. Hospital’s antibiotic-resistant and virulent K. pneumoniae, able to spread among humans, animals, and in the environment, pose a significant threat to public health. Full article
(This article belongs to the Section Bacterial Pathogens)
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21 pages, 2764 KB  
Article
First Report of Stenotrophomonas maltophilia from Canine Dermatological Infections: Unravelling Its Antimicrobial Resistance, Biofilm Formation, and Virulence Traits
by Ria Rajeev, Porteen Kannan, Sureshkannan Sundaram, Sandhya Bhavani Mohan, Sivachandiran Radjendirane, Chaudhary Jeetendrakumar Harnathbhai, Anbazhagan Subbaiyan, Viswanathan Naveenkumar, Nithya Quintoil Mohanadasse, Wilfred Ruban Savariraj, Charley A. Cull and Raghavendra G. Amachawadi
Antibiotics 2025, 14(7), 639; https://doi.org/10.3390/antibiotics14070639 - 23 Jun 2025
Viewed by 1382
Abstract
Background/Objectives: The present study was aimed at documenting S. maltophilia occurrence in dogs with skin ailments, investigating its virulence, biofilm-forming ability, antimicrobial susceptibility, and zoonotic potential to inform preventive and therapeutic strategies against multidrug resistant S. maltophilia infections. Methods: Skin swabs [...] Read more.
Background/Objectives: The present study was aimed at documenting S. maltophilia occurrence in dogs with skin ailments, investigating its virulence, biofilm-forming ability, antimicrobial susceptibility, and zoonotic potential to inform preventive and therapeutic strategies against multidrug resistant S. maltophilia infections. Methods: Skin swabs (n = 300) were collected from dogs with dermatological ailments. Isolation was performed using selective media and confirmed with molecular methods, validated by MALDI Biotyper. Antimicrobial susceptibility testing and efflux activity assessment were conducted. Resistance genes related to sulfonamides, quinolones, and β-lactams were screened. Virulence was assessed by biofilm formation, motility, and virulence gene profiling. Results: In total, 15 S. maltophilia (5%) isolates were identified. All 15 isolates were susceptible to trimethoprim-sulfamethoxazole, enrofloxacin, gatifloxacin, levofloxacin, minocycline, and tigecycline, but resistant to cefpodoxime and aztreonam. The following resistance genes qnr (93.3%), blaOXA-48 (46.7%), blaKPC (33.3%), blaNDM (33.3%), blaCTX-M (20%), blaSHV (20%), and blaTEM (6.7%) were detected. All 15 isolates displayed high efflux activity. Overall, 9 isolates (60%) were strong biofilm producers, and 6 (40%) were moderate. Virulence genes such as virB, motA, rmlA, and fliC were present in all 15 isolates, with others varying in frequency. All isolates exhibited swimming motility. Heat map clustering showed diverse profiles, with no identical isolate patterns. Correlation analysis indicated positive associations between several antimicrobial resistance and virulence genes. Conclusions: This study underscores the zoonotic potential of S. maltophilia from dogs, advocating for a One Health approach to mitigate infection risks and limit the spread of virulent multidrug resistant pathogens. Full article
(This article belongs to the Special Issue Antimicrobial Resistance and Infections in Veterinary Settings)
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