# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 2720 | 0 | 0.9977 | Phenotypic and genotypic characterization of antimicrobial resistance in Enterococcus spp. Isolated from the skin microbiota of channel catfish (Ictalurus punctatus) in Southeastern United States. BACKGROUND: Aquaculture systems may contribute to the emergence and persistence of antimicrobial-resistant (AMR) bacteria, posing risks to animal, environmental, and human health. This study characterized the phenotypic and genotypic antimicrobial resistance profiles of Enterococcus spp. isolated from the skin microbiota of 125 channel catfish (Ictalurus punctatus) harvested from two earthen ponds in Alabama, USA. METHODS: Skin swabs from the body of channel catfish were enriched in Enterococcosel broth and cultured on Enterococcosel agar at 28 °C for 24 h. Isolates were confirmed using Biolog Gen III and VITEK(®)2, and antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method. Thirty-five randomly sampled isolates underwent whole-genome sequencing for genotypic characterization. RESULTS: 36% of isolates exhibited multidrug resistance (resistance to ≥ 3 antimicrobial classes), with the highest resistance rates observed for ampicillin (44.8%), rifampicin (42.4%), and tetracycline (38.4%). The most prevalent resistance genes were aac(6')-Iid (65.7%), aac(6')-Ii (22.9%), efmA, and msr(C) (20.0% each). Plasmid replicons rep1 and repUS15 frequently co-occurred with resistance genes. Biofilm-associated genes, including efaA, fsrA, fsrB, sprE, ebpABC, ace, and scm, were commonly detected. Multivariate analyses (PERMANOVA, PCA) revealed no significant species-level differences in resistance burden or biofilm gene carriage, indicating similar resistance and virulence gene carriage across species in this dataset. CONCLUSIONS: The skin microbiota of pond-raised catfish harbors antimicrobial-resistant Enterococcus spp. with mobile resistance elements and biofilm-associated virulence factors, suggesting a potential role in AMR persistence within aquaculture settings. These findings support the need for targeted AMR surveillance in fish-associated microbiota as part of integrated One Health strategies. | 2025 | 40760424 |
| 2712 | 1 | 0.9976 | Antibiotic Resistance Profiles of Bacteria Isolated from Hotspot Environments in Bahir Dar City, Northwestern Ethiopia. BACKGROUND: Wastes generated from hotspot environments contain a wide range of antibiotics and pathogens that play a significant role in the dissemination of antibiotic-resistant bacteria in the environment. This study was carried out to isolate bacteria from hotspot environments and determine their resistance profiles to commonly used antibiotics in Bahir Dar city, Ethiopia. METHODS: A cross-sectional study was conducted from October 2020 to June 2021 in Bahir Dar City. A total of 126 waste and wastewater samples were aseptically collected, transported, and processed for bacteriological isolation and susceptibility testing following standard procedures. RESULTS: A total of 411 bacterial isolates were recovered and the highest value of 122 (29.7%) bacterial isolates were obtained from medical wastewater samples, and the most frequently isolated bacteria were assigned to the species Escherichia coli with 82 strains (19.5%). The results revealed that the highest resistance profile of 69 (95.8%) was obtained in Staphylococcus aureus against ampicillin and 46 (86.8%) Citrobacter spp. against tetracycline. Two hundred and sixteen (52.6%) of bacteria showed multi-drug resistance and the highest multi-drug resistance was observed in Pseudomonas spp. 47 (65.3%), followed by Escherichia coli 51 (62.2%). The highest resistance profile of 12 (85.7%) and 60 (74.1%) for tetracycline were obtained from beef waste and wastewater and medical wastewater samples. The highest multi-drug resistance was recorded in isolates isolated from beef waste and wastewater samples 11 (64.7%), followed by medical wastewater samples 84 (64.1%). Even though a higher (>0.2) multi-antibiotic resistance index was found in all hotspot environments, the highest multi-antibiotic resistance index (0.477) was recorded in bacteria isolated from medical wastewater. CONCLUSION: It was concluded that wastes generated from hotspot environments and released in the environment contain large numbers of antibiotic-resistant, multidrug, extensively, and pan-drug-resistant bacteria. Proper waste management strategies should be established. | 2022 | 35785260 |
| 2132 | 2 | 0.9976 | Prevailing Antibiotic Resistance Patterns in Hospitalized Patients with Urinary Tract Infections in a Vietnamese Teaching Hospital (2014 - 2021). PURPOSE: In a Vietnamese teaching hospital, this study examined the prevalence and patterns of antimicrobial resistance (AMR) of common bacteria isolated from hospitalized patients with urinary tract infections (UTIs) between 2014 and 2021. METHODS: From 4060 urine samples collected, common pathogens were isolated using quantitative culture on brilliance UTI Clarity agar and blood agar. Bacterial identification, antimicrobial susceptibility testing, and multidrug resistance (MDR) classification followed standardized techniques. Bacteria with a frequency of less than 2% were excluded. Statistical analysis was performed using R software, with the chi-square test applied and significance set at p < 0.05. RESULTS: Of 4060 urine samples collected, 892 (22.0%) had positive results for common infections. Gram-negative bacteria predominated (591/892; 66.3%), with Escherichia coli being the most prevalent (336/892; 37.7%). Enterococcus spp. (152/892; 17.0%) was the leading Gram-positive pathogen. Some antibiotics had significant resistance rates, especially in Gram-negative bacteria, with ampicillin having the greatest resistance rate (92.8%). Carbapenems and nitrofurantoin remained generally effective. Among Gram-positive bacteria, high resistance was seen for macrolides ranging from 85.5% (azithromycin) to 89.8% (erythromycin), and for tetracyclines, ranging from 0% (teicoplanin) to 85.2% (tetracycline). There was no resistance to tigecycline and teicoplanin, indicating their potential efficacy against multidrug resistance (MDR) bacteria causing UTIs. MDR rates were higher in Gram-negative bacteria (64.8% versus 43.5%), with Klebsiella pneumoniae having the highest rate (78.7%). CONCLUSION: This study underscores the urgent need for ongoing surveillance of AMR patterns in Vietnam and emphasizes the significance of efficient infection prevention methods, prudent use of antibiotics, and targeted interventions to combat antimicrobial resistance. | 2025 | 39911566 |
| 2713 | 3 | 0.9975 | Identification of Escherichia coli from broiler chickens in Jordan, their antimicrobial resistance, gene characterization and the associated risk factors. BACKGROUND: Avian pathogenic Escherichia coli (APEC) is the principle cause of colibacillosis affecting poultry. The main challenge to the poultry industry is antimicrobial resistance and the emergence of multidrug resistant bacteria that threaten the safety of the food chain. Risk factors associated with emergence of antimicrobial resistance among avian pathogenic E. coli were correlated with the inappropriate use of antimicrobials along with inadequate hygienic practices, which encourages the selection pressure of antimicrobial resistant APEC. The aim of this study was to isolate, identify, serogroup and genotype APEC from broilers, assess their antibiotic resistance profile, expressed genes and the associated risk factors. RESULTS: APEC was isolated from the visceral organs of sick chickens with a prevalence of 53.4%. The most prevalent serotypes were O1, O2, O25 and O78, in percentage of 14.8, 12.6, 4.4 and 23.7%, respectively. Virulence Associated Genes; SitA, iss, iucD, iucC, astA, tsh cvi and irp2 were detected in rate of 97.4, 93.3, 75, 74, 71, 46.5, 39 and 34%, respectively and 186 (69.2%) isolates possess > 5-10 genes. The highest resistance was found against sulphamethoxazole-trimethoprim, florfenicol, amoxicillin, doxycycline and spectinomycin in percentage; 95.5, 93.7, 93.3, 92.2 and 92.2%, respectively. Sixty-eight percent of APEC isolates were found to have at least 5 out of 8 antimicrobial resistant genes. The most predominant genes were Int1 97%, tetA 78.4%, bla TEM 72.9%, Sul1 72.4%, Sul2 70.2%. Two risk factors were found to be associated with the presence of multi-drug resistant APEC in broiler chickens, with a P value ≤0.05; the use of ground water as source of drinking water and farms located in proximity to other farms. CONCLUSIONS: This study characterized the VAGs of avian pathogenic E. coli and establish their antimicrobial resistance patterns. The widespread of antimicrobial resistance of APEC isolates and detection of ARGs highlighted the need to monitor the spread of ARGs in poultry farms and the environment in Jordan. Use of ground water and closely located farms were significant risk factors associated with the presence of MDR APEC in broiler chickens in Jordan. | 2019 | 31118039 |
| 1290 | 4 | 0.9975 | Acinetobacter baumannii in sheep, goat, and camel raw meat: virulence and antibiotic resistance pattern. Acinetobacter genus belongs to a group of Gram-negative coccobacillus. These bacteria are isolated from human and animal origins. Antimicrobial agents play a vital role in treating infectious diseases in both humans and animals, and Acinetobacter in this regard is defined as an organism of low virulence. The current study aimed to evaluate antibiotic resistance properties and virulence factor genes in Acinetobacter baumannii strains isolated from raw animal meat samples. Fresh meat samples from 124 sheep, 162 goat, and 95 camels were randomly collected from Isfahan and Shahrekord cities in Iran. Most A. baumannii strains isolated from sheep meat samples represented fimH (82.35%), aac(3)-IV (78.43%), sul1 (78.43%) and Integron Class I (96.07%) genes. Moreover, more than 50% of A. baumannii strains isolated from sheep samples were resistant to streptomycin (54.90%), gentamycin (74.50%), co-trimoxazole (70.58%), tetracycline (82.35%), and trimethoprim (62.74%). Current findings revealed significant association between the presence of fimH, cnfI, afa/draBC, dfrA1, sulI, aac(3)-IV genes in sheep samples. Furthermore, significant association was observed between fimH, cnfI, sfa/focDE and dfrA1genes in goat meat samples. In sheep meat samples, significant differences were identified in resistance to gentamicin, tetracycline, and co-trimoxazole in comparison with other antibiotics. Finally, there were statistically significant differences between the incidences of resistance to gentamicin, tetracycline, and co-trimoxazole in comparison with other antibiotics in all strains. In conclusion, the presence of virulence factors and antibiotic resistance in A. baumannii strains isolated from animal meat samples showed that animals should be considered as a potential reservoir of multidrug-resistant A. baumannii. | 2019 | 31663061 |
| 5267 | 5 | 0.9974 | Diversity and antibiotic resistance of cultivable bacteria in bulk tank milk from dairy farms in Shandong Province, China. INTRODUCTION: This study systematically analyzed bacterial diversity and antimicrobial resistance (AMR) profiles in bulk tank milk from five dairy farms (n = 30) in Shandong Province, China, to assess public health risks associated with microbial contamination and provide critical data for regional quality control and AMR risk assessment in dairy production systems. METHODS: Total bacterial counts were quantified, revealing significant inter-farm variation (P < 0.05) with a range of 3.94-6.68 log CFU/mL. Among 129 bacterial isolates, genus-level dominance and species prevalence were identified. Antimicrobial susceptibility testing (AST) against 10 agents was performed using integrated resistance criteria combining Clinical and Laboratory Standards Institute (CLSI) standards and epidemiological cutoff values (ECOFFs). Nine resistance genes targeting seven antibiotic classes were detected via PCR. RESULTS: The highest resistance rate was observed for sulfadiazine (53.2%) and the lowest for levofloxacin (6.0%). Multidrug resistance was detected in 23% (20/87) of isolates, with 14 strains meeting ECOFFs-based resistance criteria. PCR analysis showed sul1 (70.5%) and ant(4')-Ia (54.3%) as the most prevalent resistance genes, while mcr-1, lnu (B), and bla (NDM-1) were absent in all isolates. Regional resistance variations correlated significantly with farm management practices. DISCUSSION: These findings underscore the impact of historical antibiotic use on AMR dissemination. Enhanced AMR surveillance in raw milk, improved antibiotic stewardship, and targeted interventions are crucial to mitigate public health risks from microbial contamination and horizontal gene transfer of resistance determinants. | 2025 | 40771950 |
| 1285 | 6 | 0.9974 | Antimicrobial Resistance Profiles and Genes in Streptococcus uberis Associated With Bovine Mastitis in Thailand. Streptococcus uberis is recognized as an environmental mastitis pathogen in dairy cattle. The varied success rate of antibiotic treatment for S. uberis intramammary infection may be associated with the antimicrobial resistance (AMR) of these bacteria. This observational study aimed to analyze 228 S. uberis strains associated with bovine mastitis in northern Thailand from 2010 to 2017. AMR and AMR genes were determined by the minimum inhibitory concentration (MIC) using a microdilution method and polymerase chain reaction, respectively. The majority of S. uberis strains were resistant to tetracycline (187/228, 82.02%), followed by ceftiofur (44/228, 19.30%), and erythromycin (19/228, 8.33%). The MIC50 and MIC90 of ceftiofur in 2017 were 2-4-fold higher than those in 2010 (P < 0.01). Resistance to tetracycline and ceftiofur significantly increased between 2010 and 2017 (P < 0.05). The most common gene detected in S. uberis was tetM (199/228, 87.28%), followed by ermB (151/228, 66.23 %) and blaZ (15/228, 6.58 %). The association between tetracycline resistance and tetM detection was statistically significant (P < 0.01). The detection rates of tetM significantly increased, while the detection rates of tetO and ermB significantly decreased during 2010-2017. AMR monitoring for bovine mastitis pathogens, especially S. uberis, is necessary to understand the trend of AMR among mastitis pathogens, which can help create an AMR stewardship program for dairy farms in Thailand. | 2021 | 34485432 |
| 2942 | 7 | 0.9974 | Longitudinal Shedding Patterns and Characterization of Antibiotic Resistant E. coli in Pastured Goats using a Cohort Study. There is a scarcity of information on antibiotic resistance in goats. To understand shedding of resistant Escherichia coli in pastured goats, we collected fecal samples from a mixed age cohort over a one-year period. No antibiotic had been used on the study animals one year prior to and during the study period. Resistant isolates were detected in all age groups and prevalence in goat kids was significantly higher than adults; 43-48% vs 8-25% respectively. The proportion of resistant isolates was higher when animals were congregated near handling facility than on pasture. Most isolates were resistant to tetracycline (51%) and streptomycin (30%), but also to antibiotics that had never been used on the farm; ampicillin (19%). TetB, bla(-TEM), (aadA and strpA/strpB) genes were detected in 70%, 43%, (44% and 24%) of tetracycline, ampicillin, and streptomycin resistant isolates respectively. Resistant isolates also harbored virulent genes and some belonged to D and B2 phylogenetic groups. Thus, pastured goats, despite minimal exposure to antibiotics, are reservoirs of resistant E. coli that may contaminate the environment and food chain and spread resistant genes to pathogenic bacteria and some that are potential animal and human pathogens. Environmental sources may play a role in acquisition of resistant bacteria in pastured goats. | 2019 | 31480769 |
| 1284 | 8 | 0.9974 | Research Note: Molecular characterization of antimicrobial resistance and virulence gene analysis of Enterococcus faecalis in poultry in Tai'an, China. Enterococcus faecalis (E. faecalis) is a zoonotic pathogen that causes severe economic losses in the poultry-breeding industry. In our study, cecal samples from broilers with cecal enlargement at slaughterhouses in Tai'an, China, were analyzed. The results revealed that the 61 E. faecalis strains had drug resistance rates ranging from 96.72 to 8.20% against 11 antibiotics in 5 classes, of which erythromycin (96.72%) and tetracycline (96.72%) had the highest rates and vancomycin (8.20%) the lowest. The highest detection rate of multiple drug-resistant strains in 61 isolates was 72.13%. The results of polymerase chain reaction showed that, of the 12 virulence genes, ccf had the highest detection rate (80.33%), followed by asal and cob (both 78.69%), whereas hyl had the lowest (6.56%). Among 15 drug resistance genes, ermB had the highest detection rate (95.08%), followed by tetM (91.80%) and tetL (90.16%), whereas tetK (0.00%) and vanB (0.00%) remained undetected. Of the 34 sequence types found with multilocus sequence typing, the most predominant were ST631 (13.11%, 8/61) and ST634 (8.2%, 5/61). Our results provide a theoretical basis for guiding the rational use of antibiotics and preventing the spread of drug-resistant bacteria, along with epidemiological data for the risk analysis of food-borne bacteria and antimicrobial resistance in poultry farms in Shandong Province. | 2022 | 35263706 |
| 1282 | 9 | 0.9974 | Subclinical Mastitis in Selected Bovine Dairy Herds in North Upper Egypt: Assessment of Prevalence, Causative Bacterial Pathogens, Antimicrobial Resistance and Virulence-Associated Genes. Mastitis is a significant disease affecting dairy cattle farms in Egypt. The current study aimed to investigate the prevalence and major bacterial pathogens causing subclinical mastitis (SCM) in three bovine dairy herds, with a history of SCM, at three Governorates in North Upper Egypt. The antimicrobial resistance profiles and specific virulence-associated genes causing bovine SCM were investigated. One thousand sixty-quarter milk samples (QMS) were collected aseptically from 270 apparently healthy cows in three farms and examined. The total prevalence of SCM was 46% and 44.8% based on California Mastitis Test (CMT) and Somatic Cell Count (SCC), respectively. Bacteriological examination of CMT positive quarters revealed that the prevalence of bacterial isolation in subclinically mastitic quarters was 90.4% (26 and 64.3% had single and mixed isolates, respectively). The most frequent bacterial isolates were E. coli (49.8%), Staphylococcus aureus (44.9%), streptococci (44.1%) and non-aureus staphylococci (NAS) (37.1%). Antimicrobial susceptibility testing of isolates revealed a high degree of resistance to the most commonly used antimicrobial compound in human and veterinary medicine. Implementation of PCR revealed the presence of mecA and blaZ genes in 60% and 46.7% of S. aureus isolates and in 26.7% and 53.3% of NAS, respectively. Meanwhile 73.3% of streptococci isolates harbored aph(3')-IIIa gene conferring resistance to aminoglycosides and cfb gene. All E. coli isolates harbored tetA gene conferring resistance to tetracycline and sul1 gene conferring resistance to sulfonamides. The fimH and tsh genes were found in 80% and 60%, respectively. A significant association between the phenotypes and genotypes of AMR in different bacteria was recorded. The presence of a high prevalence of SCM in dairy animals impacts milk production and milk quality. The coexistence of pathogenic bacteria in milk is alarming, threatens human health and has a public health significance. Herd health improvement interventions are required to protect human health and society. | 2021 | 34072543 |
| 2727 | 10 | 0.9974 | Prevalence and Antibiotic Resistance Pattern of Streptococcus, Staphylococcus, Neisseria meningitidis and Enterobacteriaceae in Two Reference Hospitals of Yaoundé: An Overview before and during COVID-19 Pandemic Era. The COVID-19 pandemic led to tremendously use of antimicrobial due to the lack of proper treatment strategies, raising concerns about emergence of antimicrobial resistance (AMR). This study aimed at determining the prevalence and antibiotic resistance pattern of selected bacteria isolates in 02 referral health facilities in Yaoundé before and during the COVID-19 pandemic era. We conducted a retrospective study over a period of 03 years (from 1 January 2019 to 31 December 2021) in the bacteriology units of the Central and General Hospitals of Yaoundé, Cameroon. Data on bacteria genera (Streptococcus, Staphylococcus, Neisseria meningitidis and Enterobacteriaceae) as well as their corresponding specifics antibiotics: Cefixime, azythromycin and erythromycin were obtained from laboratory records. The global resistance rate of bacteria as well as their correlation with antibiotics according to COVID-19 pandemic era was determined and compared. For p < 0.05, the difference was statistically significant. In all, 426 bacterial strains were included. It appeared that the highest number of bacteria isolates and lowest rate of bacterial resistance were recorded during the pre-COVID-19 period in 2019 (160 isolates vs. 58.8% resistance rate). Conversely, lower bacteria strains but greater resistance burden were recorded during the pandemic era (2020 and 2021) with the lowest bacteria amount and peak of bacteria resistance registered in 2020, the year of COVID-19 onset (120 isolates vs. 70% resistance in 2020 and 146 isolates vs. 58.9% resistance in 2021). In contrast to almost all others groups of bacteria where the resistance burden was quite constant or decreasing over years, the Enterobacteriaceae exhibited greater resistance rate during the pandemic period [60% (48/80) in 2019 to 86.9% (60/69) in 2020 and 64.5% (61/95) in 2021)]. Concerning antibiotics, unlike erythromycin, azythromycin related resitance increased during the pandemic period and the resistance to Cefixim tends to decrease the year of the pandemic onset (2020) and re-increase one year therafter. A significant association was found between resistant Enterobacteriaceae strains and cefixime (R = 0.7; p = 0.0001) and also, between resistant Staphylococcus strains and erythromycin (R = 0.8; p = 0.0001). These retrospective data showed a herogeneous MDR bacteria rate and antibiotic resistance pattern over time before and during the COVID-19 pandemic era suggesting that antimicrobial resistance needs to be more closely monitored. | 2023 | 37237832 |
| 1288 | 11 | 0.9974 | Assessment of virulence factors and antimicrobial resistance among the Pseudomonas aeruginosa strains isolated from animal meat and carcass samples. BACKGROUND: Pseudomonas aeruginosa bacteria are emerging causes of food spoilage and foodborne diseases. Raw meat of animal species may consider a reservoir of P. aeruginosa strains. OBJECTIVES: The present survey was done to assess the prevalence, antibiotic resistance properties and distribution of virulence factors among the P. aeruginosa strains isolated from raw meat and carcass surface swab samples of animal species. METHODS: Five hundred and fifty raw meat and carcass surface swab samples were collected from cattle and sheep species referred to as slaughterhouses. P. aeruginosa bacteria were identified using culture and biochemical tests. The pattern of antibiotic resistance was determined by disk diffusion. The distribution of virulence and antibiotic resistance genes was determined using polymerase chain reaction. RESULTS: Forty-seven of 550 (8.54%) examined samples were contaminated with P. aeruginosa. The prevalence of P. aeruginosa in raw meat and carcass surface swab samples were 6.57 and 12%, respectively. P. aeruginosa isolates showed the maximum resistance rate toward penicillin (87.23%), ampicillin (85.10%), tetracycline (85.10%), gentamicin (65.95%) and trimethoprim (57.44%). The most commonly detected antibiotic resistance genes were BlaCTX-M (53.19%), blaDHA (42.55%) and blaTEM (27.65%). The most commonly detected virulence factors was ExoS (42.55%), algD (31.91%), lasA (31.91%), plcH (31.91%) and exoU (25.53%). CONCLUSIONS: Meat and carcass surface swab samples may be sources of resistant and virulent P. aeruginosa, which pose a hygienic threat in their consumption. However, further investigations are required to identify additional epidemiological features of P. aeruginosa in meat and carcass surface samples. | 2023 | 36418165 |
| 2715 | 12 | 0.9973 | From the Farms to the Dining Table: The Distribution and Molecular Characteristics of Antibiotic-Resistant Enterococcus spp. in Intensive Pig Farming in South Africa. Foodborne pathogens, including antibiotic-resistant species, constitute a severe menace to food safety globally, especially food animals. Identifying points of concern that need immediate mitigation measures to prevent these bacteria from reaching households requires a broad understanding of these pathogens' spread along the food production chain. We investigated the distribution, antibiotic susceptibility, molecular characterization and clonality of Enterococcus spp. in an intensive pig production continuum in South Africa, using the farm-to-fork approach. Enterococcus spp. were isolated from 452 samples obtained along the pig farm-to-fork continuum (farm, transport, abattoir, and retail meat) using the IDEXX Enterolert(®)/Quanti-Tray(®) 2000 system. Pure colonies were obtained on selective media and confirmed by real-time PCR, targeting genus- and species-specific genes. The susceptibility to antibiotics was determined by the Kirby-Bauer disk diffusion method against 16 antibiotics recommended by the WHO-AGISAR using EUCAST guidelines. Selected antibiotic resistance and virulence genes were detected by real-time PCR. Clonal relatedness between isolates across the continuum was evaluated by REP-PCR. A total of 284 isolates, consisting of 79.2% E. faecalis, 6.7% E. faecium, 2.5% E. casseliflavus, 0.4% E. gallinarum, and 11.2% other Enterococcus spp., were collected along the farm-to-fork continuum. The isolates were most resistant to sulfamethoxazole-trimethoprim (78.8%) and least resistant to levofloxacin (5.6%). No resistance was observed to vancomycin, teicoplanin, tigecycline and linezolid. E. faecium displayed 44.4% resistance to quinupristin-dalfopristin. Also, 78% of the isolates were multidrug-resistant. Phenotypic resistance to tetracycline, aminoglycosides, and macrolides was corroborated by the presence of the tetM, aph(3')-IIIa, and ermB genes in 99.1%, 96.1%, and 88.3% of the isolates, respectively. The most detected virulence gene was gelE. Clonality revealed that E. faecalis isolates belonged to diverse clones along the continuum with major REP-types, mainly isolates from the same sampling source but different sampling rounds (on the farm). E. faecium isolates revealed a less diverse profile. The results suggest that intensive pig farming could serve as a reservoir of antibiotic-resistant bacteria that could be transmitted to occupationally exposed workers via direct contact with animals or consumers through animal products/food. This highlights the need for more robust guidelines for antibiotic use in intensive farming practices and the necessity of including Enterococcus spp. as an indicator in antibiotic resistance surveillance systems in food animals. | 2021 | 33918989 |
| 2346 | 13 | 0.9973 | Antibiotic resistance genes and molecular typing of Streptococcus agalactiae isolated from pregnant women. BACKGROUND: The antibiotic resistance of genital tract colonizing Streptococcus agalactiae in pregnant women is increasing. We aimed to determine the antibiotic resistance genes of different clonal types of this bacterium in pregnant women. METHODS: Four hundred twenty non-repeated vaginal and rectal specimens were collected from pregnant women and were transferred to the laboratory using Todd Hewitt Broth. The samples were cultured on a selective medium, and the grown bacteria were identified by standard microbiological and biochemical tests. Antimicrobial resistance pattern and inducible clindamycin resistance of the isolates were determined using the disk agar diffusion method. The genomic DNAs of S. agalactiae strains were extracted using an extraction kit, and the antibiotic resistance genes and RAPD types were detected using the PCR method. RESULTS: The average age of the participants was 30.74 ± 5.25 years. There was a significant relationship between the weeks of pregnancy and the number of positive bacterial cultures (P-value < 0.05). Moreover, 31 pregnant women had a history of abortion, and 18 had a history of membrane rupture. Among 420 specimens, 106 S. agalactiae isolates were detected. The highest antibiotic resistance rate was found against tetracycline (94.33%), and all isolates were susceptible to linezolid. Moreover, 15, 15, 42, and 7 isolates showed an iMLS(B), M-, cMLS(B), and L-phenotype. The ermB was the most prevalent resistance gene in the present study, while 38 (35.84%), 8 (7.54%), 79 (74.52%), 37 (34.9%), and 20 (18.86%) isolates were contained the ermTR, mefA/E, tetM, tetO, and aphA3 gene, respectively. CONCLUSIONS: The high-level antibiotic resistance and prevalence of resistance genes may be due to the arbitrarily use, livestock industry consumption, and the preventive use of antibiotics in pregnant women. Thus, the need to re-considering this problem seems to be necessary. | 2023 | 36658541 |
| 2649 | 14 | 0.9973 | Multidrug Resistance and Virulence Traits of Salmonella enterica Isolated from Cattle: Genotypic and Phenotypic Insights. Background/Objective: Non-typhoidal Salmonella is a leading cause of foodborne illness worldwide and presents a significant One Health concern due to zoonotic transmission. Although antibiotic therapy remains a standard approach for treating salmonellosis in severe cases in animals, the widespread misuse of antibiotics has contributed to the emergence of multidrug-resistant (MDR) Salmonella strains. This study provides insights into the genotypic and phenotypic characteristics among Salmonella isolates from necropsied cattle. Methods: A total of 1008 samples were collected from necropsied cattle. Salmonella enterica subspecies were identified by MALDI-TOF MS and subsequently confirmed by serotyping. The biofilm-forming ability of the isolated bacteria was assessed using a crystal violet assay. The motility of the isolates was assessed on soft agar plates. Additionally, the antimicrobial resistance genes (ARGs) and virulence genes were investigated. Antimicrobial resistance patterns were investigated against 19 antibiotics representing 9 different classes. Results:Salmonella species were isolated and identified in 27 necropsied cattle. Salmonella Dublin was the most prevalent serotype (29.6%). Additionally, all the isolates were biofilm producers at different levels of intensity, and 96.3% of the isolates exhibited both swarming and swimming motility. Furthermore, virulence genes, including invA, hilA, fimA, and csgA, were detected in all the isolates. The highest resistance was observed to macrolides (azithromycin and clindamycin) (100%), followed by imipenem (92.6%), and chloramphenicol (85.2%). All isolates were multidrug-resistant, with a multiple antibiotic resistance (MAR) index ranging between 0.32 and 0.74. The aminoglycoside resistance gene aac(6')-Ib was detected in all the isolates (100%), whereas the distribution of other antimicrobial resistance genes (ARGs) varied among the isolates. Conclusions: The increasing prevalence of MDR Salmonella poses a significant public health risk. These resistant strains can reduce the effectiveness of standard treatments and elevate outbreak risks. Strengthening surveillance and regulating antibiotic use in livestock are essential to mitigating these threats. | 2025 | 40723992 |
| 2721 | 15 | 0.9973 | A large sampling study on the occurrence and characteristics of Pseudomonas aeruginosa and heterotrophic bacteria in mineral water over seasons and in different containers. This study investigated the presence of Pseudomonas aeruginosa and heterotrophic bacteria in 1150 samples of bottled mineral water. P. aeruginosa was initially isolated using membrane filtration on selective agar and subsequently confirmed by PCR. Further characterization included pulsed-field gel electrophoresis (PFGE), detection of virulence genes, antimicrobial resistance profiling, Caco-2 cell invasion, and biofilm formation on different packaging materials. P. aeruginosa was detected in 11.5 % of samples, with the highest prevalence in reusable 20 L plastic jugs. PFGE revealed 41 distinct genetic profiles, indicating high diversity. The most frequent virulence genes detected were phzM (89.5 %), ExoS (88.8 %), toxA (86.8 %), and lasB (79.8 %). The more clinically relevant gene ExoU was found in 10.5 % of isolates. Antibiotic susceptibility tests showed that 14 % of isolates were multidrug-resistant, with resistance to piperacillin-tazobactam (26 %), gentamicin (18 %), and fluoroquinolones (12 %). Caco-2 cell assays showed that 73 % of strains exhibited high invasion potential (37.9-62.3 %), comparable to clinical isolates. Biofilm assays demonstrated strong adherence to materials commonly used in bottled water packaging, with the highest biofilm density observed on polypropylene. These findings suggest that reusable containers may be more prone to persistent contamination. Although the overall occurrence of P. aeruginosa was low, the presence of multidrug-resistant and virulent strains raises concerns, especially for immunocompromised individuals. These results emphasize the need for strict hygienic practices, particularly in reusable packaging systems, and routine microbial monitoring to ensure the microbiological safety of bottled mineral water. | 2025 | 40925222 |
| 2680 | 16 | 0.9973 | Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks. Backyard birds are small flocks that are more common in developing countries. They are used for poultry meat and egg production. However, they are also implicated in the maintenance and transmission of several zoonotic diseases, including multidrug-resistant bacteria. Enterococci are one of the most common zoonotic bacteria. They colonize numerous body sites and cause a wide range of serious nosocomial infections in humans. Therefore, the objective of the present study was to investigate the diversity in Enterococcus spp. in healthy birds and to determine the occurrence of multidrug resistance (MDR), multi-locus sequence types, and virulence genes and biofilm formation. From March 2019 to December 2020, cloacal swabs were collected from 15 healthy backyard broiler flocks. A total of 90 enterococci strains were recovered and classified according to the 16S rRNA sequence into Enterococcus faecalis (50%); Enterococcus faecium (33.33%), Enterococcus hirae (13.33%), and Enterococcus avium (3.33%). The isolates exhibited high resistance to tetracycline (55.6%), erythromycin (31.1%), and ampicillin (30%). However, all of the isolates were susceptible to linezolid. Multidrug resistance (MDR) was identified in 30 (33.3%) isolates. The enterococci AMR-associated genes ermB, ermA, tetM, tetL, vanA, cat, and pbp5 were identified in 24 (26.6%), 11 (12.2%), 39 (43.3%), 34 (37.7%), 1 (1.1%), 4 (4.4%), and 23 (25.5%) isolates, respectively. Of the 90 enterococci, 21 (23.3%), 27 (30%), and 36 (40%) isolates showed the presence of cylA, gelE, and agg virulence-associated genes, respectively. Seventy-three (81.1%) isolates exhibited biofilm formation. A statistically significant correlation was obtained for biofilm formation versus the MAR index and MDR. Multi-locus sequence typing (MLST) identified eleven and eight different STs for E. faecalis and E. faecium, respectively. Seven different rep-family plasmid genes (rep1-2, rep3, rep5-6, rep9, and rep11) were detected in the MDR enterococci. Two-thirds (20/30; 66.6%) of the enterococci were positive for one or two rep-families. In conclusion, the results show that healthy backyard chickens could act as a reservoir for MDR and virulent Enterococcus spp. Thus, an effective antimicrobial stewardship program and further studies using a One Health approach are required to investigate the role of backyard chickens as vectors for AMR transmission to humans. | 2022 | 35326843 |
| 2655 | 17 | 0.9973 | Prevalence, virulence factors, and antibiotic resistance of Staphylococcus aureus in seafood products. INTRODUCTION: Seafood contamination by bacteria is a pervasive issue, contributing to foodborne illnesses. This study investigates the prevalence, virulence factors, and antibiotic resistance in Staphylococcus aureus (S. aureus) isolated from various seafood products. METHODS: A total of 460 samples, including fresh, smoked, salted, and dried fish, as well as oysters, crab, lobster, and shrimp, were collected in Shahrekord, Iran. S. aureus isolation followed ISO standards, with confirmation via PCR for 16S rRNA and nuc genes. Antibiotic susceptibility was determined via Kirby-Bauer disc diffusion, while PCR detected enterotoxin and antibiotic resistance genes. FINDINGS: S. aureus was prevalent in all seafood types, with 27.83% positivity. Methicillin-resistant S. aureus (MRSA) was found in most samples, except oysters and crabs. Virulence genes were common, with Sea, Seb, Sed, Sec, and See being the most prevalent. High resistance to penicillin G and ampicillin (70%- 100%) was observed. Resistance varied for other antibiotics, with linezolid showing 100% susceptibility. The mecA gene was present in over 50% of isolates, with blaZ being the most detected resistance gene. CONCLUSION: The study underscores the need for Good Hygiene Practices (GHP) in seafood processing to mitigate S. aureus transmission. While specific comparisons between sample types were limited, the findings emphasize the prevalence of virulence factors and antibiotic resistance in seafood-associated S. aureus, highlighting the importance of vigilant food safety measures. | 2025 | 40247155 |
| 2157 | 18 | 0.9973 | Prevalence and antibiotic resistance pattern of bacteria isolated from urinary tract infections in Northern Iran. BACKGROUND: This study aimed to investigate the bacteria associated with urinary tract infection (UTI) and antibiotic susceptibility pattern of the isolates during 2013-2015 in Northern Iran. MATERIALS AND METHODS: Overall 3798 patients with clinical symptoms of UTI were subjected as samples, and they were cultured and pure isolated bacteria were identified using biochemical tests and subjected to antibiogram assessment using disc diffusion method. RESULTS: Totally, 568 (14.96%) from 3798 patients had positive UTI. Four hundred and ninety-seven (87.5%) from 568 isolated bacteria were resistant to at least one antibiotic. Escherichia coli, Staphylococcus spp., and Pseudomonas spp. were the most prevalent bacteria. Isolated bacteria indicated the highest antibiotic resistance to methicillin (76.06%) and ampicillin (89.29%) and also revealed the most sensitivity to imipenem (99.1%) and amikacin (91.57%). Statistical analysis of the resistance pattern trend during 3 years indicated the insignificant increase (P > 0.05) in antibiotic resistance of the isolates. CONCLUSION: The results of this study revealed a great concern for emerging UTI-related multidrug-resistant strains of bacteria causing UTI in Iran. | 2017 | 29026424 |
| 2706 | 19 | 0.9973 | Prevalence and antimicrobial resistance profile of bacterial foodborne pathogens in Nile tilapia fish (Oreochromis niloticus) at points of retail sale in Nairobi, Kenya. Proteus spp., Staphylococcus spp., Pseudeomonas spp., and pathogenic Vibrios are among the major foodborne pathogens associated with the consumption of contaminated fish. The increasing occurrence of antimicrobial resistance in these pathogens is a serious public health concern globally and therefore continuous monitoring of antimicrobial resistance of these bacteria along the food chain is crucial for for control of foodborne illnesses. The aim of this study was to assess the prevalence, antimicrobial resistance patterns, antibiotic resistance genes, and genetic diversity of bacterial foodborne pathogens recovered from fresh Nile tilapia (Oreochromis niloticus) obtained from retail markets in Nairobi, Kenya. A total of 68 O. niloticus fish with an average weight of 300.12 ± 25.66 g and body length of 23.00 ± 0.82 cm were randomly sampled from retail markets and tested for the presence of Proteus, Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholerae, and Vibrio parahaemolyticus. Standard culture-based microbiological and Kirby-Bauer agar disk diffusion methods were used to isolate and determine the antimicrobial resistance patterns of the isolates to 11 selected antibiotics. Statistical analysis was performed using Minitab v17.1, with p < 0.05 considered significant. The genetic diversity of the multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria was determined using 16S rRNA sequencing and phylogenetic analysis, and polymerase chain reaction (PCR) was used for detection of antibiotic resistance genes in MDR bacterial isolates. High levels of bacterial contamination were detected in fresh O. niloticus fish (44/68, 64.71%). The most prevalent bacteria were Proteus spp. (44.12%), with the rest of the bacterial species registering a prevalence of 10.29%, 4.41%, 2.94%, and 2.94% (for S. aureus, P. aeruginosa, V. cholerae, and V. parahaemolyticus, respectively). Antimicrobial resistance was detected in all the bacteria species and all the isolates were resistant to at least one antibiotic except cefepime (30 µg). Additionally, 86.36% of the isolates exhibited multidrug resistance, with higher multiple antibiotic resistance indices (MAR index >0.3) indicating that fresh O. niloticus fish were highly contaminated with MDR bacteria. Results of 16S rRNA sequences, BLASTn analysis, and phylogenetic trees confirmed the identified MDR bacterial isolates as Proteus mirabilis and other Proteus spp., S. aureus, P. aeruginosa, V. cholerae, and V. parahaemolyticus. PCR analysis confirmed the presence of multiple antibiotic resistance genes blaTEM-1, blaCMY-2, tetA, tetC, Sul2, dfrA7, strA, and aadA belonging to β-lactamases, tetracycline, sulfonamide, trimethoprim, and aminoglycosides in all the MDR bacterial isolates. There was strong correlation between antibiotic- resistant genes and phenotypic resistance to antibiotics of MDR bacteria. This study showed high prevalence of multidrug resistance among foodborne bacterial isolates from fresh O. niloticus fish obtained from retail markets. From this study, we conclude that fresh O. niloticus fish are a potential source of MDR bacteria, which could be a major risk to public health as a consequence of their dissemination along the human food chain. These results highlight the prevalence of antimicrobial-resistant foodborne pathogens in fish purchased from retail markets and underscore the risk associated with improper handling of fish. | 2023 | 39816642 |