# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 2680 | 0 | 1.0000 | 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 |
| 2681 | 1 | 0.9999 | Determination of the Prevalence and Antimicrobial Resistance of Enterococcus faecalis and Enterococcus faecium Associated with Poultry in Four Districts in Zambia. The presence of antimicrobial-resistant Enterococci in poultry is a growing public health concern worldwide due to its potential for transmission to humans. The aim of this study was to determine the prevalence and patterns of antimicrobial resistance and to detect drug-resistant genes in Enterococcus faecalis and E. faecium in poultry from four districts in Zambia. Identification of Enterococci was conducted using phenotypic methods. Antimicrobial resistance was determined using the disc diffusion method and antimicrobial resistance genes were detected using polymerase chain reaction and gene-specific primers. The overall prevalence of Enterococci was 31.1% (153/492, 95% CI: 27.1-35.4). Enterococcus faecalis had a significantly higher prevalence at 37.9% (58/153, 95% CI: 30.3-46.1) compared with E. faecium, which had a prevalence of 10.5% (16/153, 95% CI: 6.3-16.7). Most of the E. faecalis and E. faecium isolates were resistant to tetracycline (66/74, 89.2%) and ampicillin and erythromycin (51/74, 68.9%). The majority of isolates were susceptible to vancomycin (72/74, 97.3%). The results show that poultry are a potential source of multidrug-resistant E. faecalis and E. faecium strains, which can be transmitted to humans. Resistance genes in the Enterococcus species can also be transmitted to pathogenic bacteria if they colonize the same poultry, thus threatening the safety of poultry production, leading to significant public health concerns. | 2023 | 37107019 |
| 1286 | 2 | 0.9999 | High prevalence of antibiotic resistance in pathogenic foodborne bacteria isolated from bovine milk. This study aimed to investigate the prevalence of foodborne pathogenic bacteria in bovine milk, their antibiogram phenotype, and the carriage of antibiotic resistance genes. Raw bovine milk samples (n = 100) were randomly collected from different suppliers in the northwest of Iran. Antibiotic-resistant patterns and the presence of antibiotic resistance genes were evaluated in the isolates. Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp. were isolated from 78%, 47%, 25%, and 21% of samples, respectively. All isolates showed high rates of resistance to amoxicillin, penicillin, and cefalexin. The bla(TEM) and bla(SHV) genes were detected in 50.0% and 6.4% of E. coli isolates, respectively. Also, 28.5% and 19.0% of Salmonella isolates were positive for bla(TEM) and bla(SHV). The frequency of mecA and bla(Z) in S. aureus isolates was 20.0% and 12.0%, respectively. The high prevalence of bovine milk contamination with antimicrobial-resistant species in this study necessitates precise control on antibiotic prescription in veterinary medicine. | 2022 | 35264647 |
| 2678 | 3 | 0.9999 | Phenotypic and molecular characterization of multidrug-resistant mastitis causing pathogens in dairy cattle. This study focused on isolating antibiotic-resistant mastitogens from cow milk; 57% of 100 samples tested positive by California mastitis test. Bacterial species from each milk sample were isolated and identified using Vitek® 2 automated system. Out of the 167 bacterial strains isolated, 14 were multidrug-resistant (MDR) and were further identified as belonging to Staphylococcus spp. Enterobacter spp. Morganella spp. and Elizabethkingia spp. Staphylococcus strains showed the highest resistance by phenotypic and genotypic screening, with 8% of mastitis isolates identified as MDR. These MDR bacterial strains were also found to harbour antibiotic resistance genes such as mecA (21%), blaZ (43%), gyrA (50%), and gyrB (59%). The tissue culture plate assay showed 11 multidrug-resistant bacteria as strong biofilm formers and the biofilm-related atlE gene was analysed from Staphylococcal strain M33.1. The findings highlight a public health risk from resistant dairy bacteria, emphasizing prophylactic measures and responsible antimicrobial use to prevent zoonotic transmission. | 2025 | 41115007 |
| 1200 | 4 | 0.9999 | Virulence and Antimicrobial Resistance Patterns of Salmonella spp. Recovered From Migratory and Captive Wild Birds. BACKGROUND: Salmonella spp., especially those are resistant to extended-spectrum β-lactamase (ESBL), are considered as major concern to global health due to their emergence and dissemination. AIM: The aim of this study was to investigate the virulence and antimicrobial resistance (AMR) profile of Salmonella spp. from migratory and captive wild birds. METHOD: A total 262 faecal samples were collected, and the identification of Salmonella spp. was carried out using a standard culture and PCR as well as molecular detection of virulence and AMR genes. RESULTS: The overall prevalence of Salmonella was determined to be 30.92% (95% CI = 25.63-36.75). Migratory birds exhibited highest prevalence (38.10%), whereas wild birds in captivity showed a lower prevalence (23.40%). The agfA gene was detected at a higher rate at 24.69%. Salmonella spp. exhibited 100% resistance to tetracycline, followed by 58% ampicillin and 46% streptomycin. In addition, there was a resistance rate to ceftriaxone of 17% and to colistin sulphate of 25%. Interestingly, levofloxacin alone displayed 100% sensitivity across all isolates, while ciprofloxacin and azithromycin showed 73% and 64% sensitivity, respectively. The MAR index was 0.25 and 0.42, and 74.07% of all isolates showed multidrug resistance (MDR). It was shown that migratory and captive wild birds contained ESBL genes blaTEM (94.34% and 49.06%) and blaSHV (13.33% and 10%), respectively. Genes responsible for sulphonamide (sul1) resistance were detected in 13.33% and 79% of wild and migratory birds, respectively. CONCLUSION: Salmonella has been found in captive wild and migratory birds and could act as reservoirs for the transmission of MDR and ESBL bacteria. | 2024 | 39494993 |
| 2679 | 5 | 0.9999 | Detection and Molecular Characterization of Staphylococci from Eggs of Household Chickens. Eggs are a healthy and nutritious food source, but may be contaminated by bacteria. Previous studies have reported the presence of staphylococci in eggs of farmed chickens, but no study has evaluated the staphylococcal population of eggs from household chickens. In this study, staphylococci from eggs (n = 275) of household chickens collected from November 2016 to March 2017 from different villages of Khyber Pakhtunkhwa province, Pakistan, were characterized. Seven species of staphylococci were identified from 65 eggs, including the predominant species, Staphylococcus xylosus (49/275; 17.8%). S. xylosus isolates (n = 73) were tested for antimicrobial susceptibility, presence of resistance genes, genetic relatedness, and inhibitory activity against other bacteria. The majority of isolates were resistant to oxacillin (83.6%) and tetracycline (24.7%), but also exhibited resistance to daptomycin and linezolid (5.5% each). Of the 10 resistance genes tested, isolates were only positive for mecA (35.6%; 26/73), mecC/C1 (2.7%; 2/73), and tet(K) (14/73; 19%). Using pulsed-field gel electrophoresis (PFGE), nine clusters had identical PFGE patterns. Isolates produced inhibitory activity against a broad spectrum of bacteria; 20.5%, 19.2%, 17.8%, and 16.4% of S. xylosus were able to inhibit growth of Salmonella enterica serotype Typhi, methicillin-susceptible Staphylococcus aureus, Escherichia coli, and methicillin-resistant Staphylococcus aureus, respectively. This study demonstrated the presence of genetically related antimicrobial-resistant S. xylosus from eggs from household chickens. Like table eggs, eggs of household chickens also contain staphylococci that may be resistant to antimicrobials used to treat human infections. These data will allow comparison between staphylococci from eggs from different sources and may indicate the relative safety of eggs from household chickens. Further study of these egg types and their microbial composition is warranted. | 2019 | 31009262 |
| 2972 | 6 | 0.9999 | Genetic characterisation of class 1 integrons among multidrug-resistant Salmonella serotypes in broiler chicken farms. OBJECTIVES: Antimicrobial resistance in Salmonella serotypes has been reported. Integrons play an important role in the dissemination of antimicrobial resistance genes in bacteria. Scarce literature is available on the identification of integrons in Salmonella isolated from broiler chickens. In this study, antimicrobial susceptibility testing and characterisation of class 1 integrons among multidrug-resistant (MDR) Salmonella enterica serotypes in broiler chicken farms in Egypt were performed. METHODS: Antimicrobial susceptibility was determined by the disk diffusion method. PCR was performed to detect antimicrobial resistance genes and class 1 integrons in the tested Salmonella serotypes. Gene sequencing of the variable region of a class 1 integron was performed. RESULTS: Salmonella spp. were detected in 26 (13.5%) of 192 broiler samples, with Salmonella Enteritidis being the most frequently detected serotype, followed by Salmonella Kentucky and Salmonella Typhimurium and other serotypes. A very high resistance rate was observed to trimethoprim/sulfamethoxazole (100%), whilst a low resistance rate was observed to cefuroxime (57.7%). MDR S. enterica isolates displayed resistance to ciprofloxacin and azithromycin. Class 1 integrons were detected in 20 (76.9%) of the 26 Salmonella isolates. A high prevalence of class 1 integrons, as the first recorded percentage in the literature, associated with MDR Salmonella isolates was observed. CONCLUSIONS: Antimicrobial resistance rates in Salmonella serotypes from broiler chicken farms were alarming, especially for ciprofloxacin and azithromycin. Thus, another therapeutic strategy other than antimicrobials is recommended to prevent outbreaks of MDR Salmonella. | 2018 | 29684574 |
| 2670 | 7 | 0.9998 | Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China. INTRODUCTION: Streptococcus agalactiae (S. agalactiae) is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock sector. To understand the distribution and drug resistance characteristics of S. agalactiae from dairy cow mastitis cases in China, multilocus sequence typing (MLST) was carried out and the serotypes and drug resistance characteristics of the bacteria in the region were analysed. MATERIAL AND METHODS: A total of 21 strains of bovine S. agalactiae were characterised based on MLST, molecular serotyping, antimicrobial susceptibility testing, and the presence of drug resistance genes. RESULTS: The serotypes were mainly Ia and II, accounting for 47.6% and 42.9% of all serotypes, respectively. Five sequence types (STs) were identified through MLST. The ST103 and ST1878 strains were predominant, with rates of 52.4% and 28.6%, respectively. The latter is a novel, previously uncharacterised sequence type. More than 90% of S. agalactiae strains were susceptible to penicillin, oxacillin, cephalothin, ceftiofur, gentamicin, florfenicol and sulfamethoxazole. The bacteria showed high resistance to tetracycline (85.7%), clindamycin (52.1%) and erythromycin (47.6%). Resistant genes were detected by PCR, the result of which showed that 47.6%, 33.3% and 38.1% of isolates carried the tet(M), tet(O) and erm(B) genes, respectively. CONCLUSION: The results of this study indicate that S. agalactiae show a high level of antimicrobial resistance. It is necessary to monitor the pathogens of mastitis to prevent the transmission of these bacteria. | 2023 | 38143824 |
| 2668 | 8 | 0.9998 | Genotyping and distribution of putative virulence factors and antibiotic resistance genes of Acinetobacter baumannii strains isolated from raw meat. BACKGROUND: Acinetobacter baumannii strains with multiple antimicrobial resistance are primarily known as opportunistic nosocomial bacteria but they may also be regarded as emerging bacterial contaminants of food samples of animal origin. Here we aimed to study the molecular characteristics of the A. baumanni strains isolated from raw meat samples. METHODS: A total of 22 A. baumanni strains were isolated from 126 animal meat samples and were genotyped by ERIC-PCR method and by PCR detection of their virulence and antimicrobial resistance determinants. A. baumannii strains with 80% and more similarities were considered as one cluster. RESULTS: Sixteen different genetic clusters were found amongst the 22 A. baumanni strains. Of the 22 strains, 12 (54.54%) had similar genetic cluster. A. baumannii strains exhibited the highest percentage of resistance against tetracycline (90.90%), trimethoprim (59.09%), cotrimoxazole (54.54%) and gentamicin (50.00%). TetA (81.81%), tetB (72.72%), dfrA1 (63.63%), aac(3)-IV (63.63%), sul1 (63.63%) and aadA1 (45.45%) were the most commonly detected antibiotic resistance genes. FimH (81.81%), afa/draBC (63.63%), csgA (63.63%), cnf1 (59.09%), cnf2 (54.54%) and iutA (50.00%) were the most commonly detected virulence factors. A. baumannii strains isolated from the chicken meat samples had the highest similarities in the genetic cluster. CONCLUSIONS: A. baumannii strains with similar genetic cluster (ERIC-Type) had the same prevalence of antibiotic resistance, antibiotic resistance genes and virulence factors. Genetic cluster of the A. baumannii strains is the main factor affected the similarities in the genotypic and phenotypic properties of the A. baumannii strains. | 2018 | 30323923 |
| 2662 | 9 | 0.9998 | Nasal Carriage of Methicillin-Resistant Staphylococcus Sciuri Group by Residents of an Urban Informal Settlement in Kenya. BACKGROUND: The Staphylococcus sciuri group constitutes animal-associated bacteria but can comprise up to 4% of coagulase-negative staphylococci isolated from human clinical samples. They are reservoirs of resistance genes that are transferable to Staphylococcus aureus but their distribution in communities in sub-Saharan Africa is unknown despite the clinical importance of methicillin-resistant S. aureus. OBJECTIVES: We characterised methicillin-resistant S. sciuri group isolates from nasal swabs of presumably healthy people living in an informal settlement in Nairobi to identify their resistance patterns, and carriage of two methicillin resistance genes. METHOD: Presumptive methicillin-resistant S. sciuri group were isolated from HardyCHROM™ methicillin-resistant S. aureus media. Isolate identification and antibiotic susceptibility testing were done using the VITEK(®)2 Compact. DNA was extracted using the ISOLATE II genomic kit and polymerase chain reaction used to detect mecA and mecC genes. Results: Of 37 presumptive isolates, 43% (16/37) were methicillin-resistant including - S. sciuri (50%; 8/16), S. lentus (31%; 5/16) and S. vitulinus (19%; 3/16). All isolates were susceptible to ciprofloxacin, gentamycin, levofloxacin, moxifloxacin, nitrofurantoin and tigecycline. Resistance was observed to clindamycin (63%), tetracycline (56%), erythromycin (56%), sulfamethoxazole/trimethoprim (25%), daptomycin (19%), rifampicin (13%), doxycycline, linezolid, and vancomycin (each 6%). Most isolates (88%; 14/16) were resistant to at least 2 antibiotic combinations, including methicillin. The mecA and mecC genes were identified in 75% and 50% of isolates, respectively. CONCLUSION: Colonizing S. sciuri group bacteria can carry resistance to methicillin and other therapeutic antibiotics. This highlights their potential to facilitate antimicrobial resistance transmission in community and hospital settings. Surveillance for emerging multidrug resistant strains should be considered in high transmission settings where human-animal interactions are prevalent. Our study scope precluded identifying other molecular determinants for all the observed resistance phenotypes. Larger studies that address the prevalence and risk factors for colonization with S. sciuri group and adopt a one health approach can complement the surveillance efforts. | 2023 | 37529492 |
| 2974 | 10 | 0.9998 | Diversity of Virulence Genes in Multidrug Resistant Escherichia coli from a Hospital in Western China. BACKGROUND: Escherichia coli strains are the most commonly isolated bacteria in hospitals. The normally harmless commensal E. coli can become a highly adapted pathogen, capable of causing various diseases both in healthy and immunocompromised individuals, by acquiring a combination of mobile genetic elements. Our aim was to characterize E. coli strains from a hospital in western China to determine their virulence and antimicrobial resistance potential. METHODS: A total of 97 E. coli clinical isolates were collected from the First Affiliated Hospital of Chengdu Medical College from 2015 to 2016. Microbiological methods, PCR, and antimicrobial susceptibility tests were used in this study. RESULTS: The frequency of occurrence of the virulence genes fimC, irp2, fimH, fyuA, lpfA, hlyA, sat, and cnf1 in the E. coli isolates was 93.81, 92.78, 91.75, 84.54, 41.24, 32.99, 28.86, and 7.22%, respectively. Ninety-five (97.9%) isolates carried two or more different virulence genes. Of these, 44 (45.4%) isolates simultaneously harbored five virulence genes, 24 (24.7%) isolates harbored four virulence genes, and 17 (17.5%) isolates harbored six virulence genes. In addition, all E. coli isolates were multidrug resistant and had a high degree of antimicrobial resistance. CONCLUSION: These results indicate a high frequency of occurrence and heterogeneity of virulence gene profiles among clinical multidrug resistant E. coli isolates. Therefore, appropriate surveillance and control measures are essential to prevent the further spread of these isolates in hospitals. | 2019 | 31824179 |
| 2675 | 11 | 0.9998 | Prevalence and Zoonotic Risk of Multidrug-Resistant Escherichia coli in Bovine Subclinical Mastitis Milk: Insights Into the Virulence and Antimicrobial Resistance. The emergence of antibiotic-resistant microorganisms has made antimicrobial resistance a global issue, and milk is a potential source for the propagation of resistant bacteria causing zoonotic diseases. Subclinical mastitis (SCM) cases, often overlooked and mixed with normal milk in dairy farms, frequently involve E. coli, which can spread through contaminated milk. We conducted this study to determine the prevalence of virulence genes, antibiotic resistance genes (ARGs), antimicrobial susceptibility, and the genetic relatedness of multidrug-resistant (MDR) Shiga toxin-producing E. coli (STEC) isolated from SCM milk. SCM-positive bovine milk was subjected to E. coli detection using cultural, biochemical, and molecular methods. Further, we detected STEC virulence genes including stx1, stx2, and eaeA. STEC isolates were tested for ARGs including blaSHV, CITM, tetA, and aac(3)-IV, and underwent antimicrobial susceptibility tests. Moreover, we performed a phylogenetic analysis of the stx1 gene of MDR-STEC. SCM was detected in 47.2% of milk samples of which 50.54% were E. coli positive. About 17.20% of E. coli isolates contained STEC virulence genes, and stx2 was the most prevalent. Moreover, all STEC isolates harbored at least one of the ARGs, while about 43.75% of the isolates carried multiple ARGs. Additionally, all the STEC isolates showed multidrug resistance, and were found to be fully resistant against amoxicillin, followed by ampicillin (87.50%) and gentamycin (75%); and were mostly sensitive to aztreonam (81.25%) and meropenem (68.75%). In phylogeny analysis, the stx1 gene of isolated MDR-STEC showed close relatedness with disease-causing non-O157 and O157 strains of different sources including cattle, humans, and food. | 2025 | 39816483 |
| 2358 | 12 | 0.9998 | Genotypic and Phenotypic Evaluation of Biofilm Production and Antimicrobial Resistance in Staphylococcus aureus Isolated from Milk, North West Province, South Africa. Background: Biofilm formation in S. aureus may reduce the rate of penetration of antibiotics, thereby complicating treatment of infections caused by these bacteria. The aim of this study was to correlate biofilm-forming potentials, antimicrobial resistance, and genes in S. aureus isolates. Methods: A total of 64 milk samples were analysed, and 77 S. aureus were isolated. Results: Seventy (90.9%) isolates were biofilm producers. The ica biofilm-forming genes were detected among 75.3% of the isolates, with icaA being the most prevalent (49, 63.6%). The icaB gene was significantly (P = 0.027) higher in isolates with strong biofilm formation potentials. High resistance (60%-90%) of the isolates was observed against ceftriaxone, vancomycin, and penicillin, and 25 (32.5%) of S. aureus showed multidrug resistance (MDR) to at least three antibiotics. Five resistance genes, namely blaZ (29, 37.7%), vanC (29, 37.7%), tetK (24, 31.2%), tetL (21, 27.3%), and msrA/B (16, 20.8%) were detected. Most MDR phenotypes possessed at least one resistance gene alongside the biofilm genes. However, no distinct pattern was identified among the resistance and biofilm phenotypes. Conclusions: The high frequency of potentially pathogenic MDR S. aureus in milk samples intended for human consumption, demonstrates the public health relevance of this pathogen in the region. | 2020 | 32252278 |
| 1196 | 13 | 0.9998 | Prediction of Phenotypic Antimicrobial Resistance Profiles From Whole Genome Sequences of Non-typhoidal Salmonella enterica. Surveillance of antimicrobial resistance (AMR) in non-typhoidal Salmonella enterica (NTS), is essential for monitoring transmission of resistance from the food chain to humans, and for establishing effective treatment protocols. We evaluated the prediction of phenotypic resistance in NTS from genotypic profiles derived from whole genome sequencing (WGS). Genes and chromosomal mutations responsible for phenotypic resistance were sought in WGS data from 3,491 NTS isolates received by Public Health England's Gastrointestinal Bacteria Reference Unit between April 2014 and March 2015. Inferred genotypic AMR profiles were compared with phenotypic susceptibilities determined for fifteen antimicrobials using EUCAST guidelines. Discrepancies between phenotypic and genotypic profiles for one or more antimicrobials were detected for 76 isolates (2.18%) although only 88/52,365 (0.17%) isolate/antimicrobial combinations were discordant. Of the discrepant results, the largest number were associated with streptomycin (67.05%, n = 59). Pan-susceptibility was observed in 2,190 isolates (62.73%). Overall, resistance to tetracyclines was most common (26.27% of isolates, n = 917) followed by sulphonamides (23.72%, n = 828) and ampicillin (21.43%, n = 748). Multidrug resistance (MDR), i.e., resistance to three or more antimicrobial classes, was detected in 848 isolates (24.29%) with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines being the most common MDR profile (n = 231; 27.24%). For isolates with this profile, all but one were S. Typhimurium and 94.81% (n = 219) had the resistance determinants bla(TEM-1,)strA-strB, sul2 and tet(A). Extended-spectrum β-lactamase genes were identified in 41 isolates (1.17%) and multiple mutations in chromosomal genes associated with ciprofloxacin resistance in 82 isolates (2.35%). This study showed that WGS is suitable as a rapid means of determining AMR patterns of NTS for public health surveillance. | 2018 | 29636749 |
| 1287 | 14 | 0.9998 | Frequently used therapeutic antimicrobials and their resistance patterns on Staphylococcus aureus and Escherichia coli in mastitis affected lactating cows. Mastitis is one of the most frequent and costly production diseases of dairy cattle. It is frequently treated with broad-spectrum antimicrobials. The objectives of this work were to investigate the prevalence of Staphylococcus aureus and Escherichia coli, find out the antimicrobials used in mastitis treatment, and explore the antimicrobial resistance profile including detection of resistance genes. Bacterial species and antimicrobial resistance genes were confirmed by the polymerase-chain reaction. A total of 450 cows were screened, where 23 (5.11%) and 173 (38.44%) were affected with clinical and sub-clinical mastitis, respectively. The prevalence of S. aureus was 39.13% (n = 9) and 47.97%(n = 83) while, E. coli was 30.43% (n = 7) and 15.60% (n = 27) in clinical and sub-clinical mastitis affected cows, respectively. The highest antimicrobials used for mastitis treatment were ciprofloxacin (83.34%), amoxycillin (80%) and ceftriaxone (76.67%). More than, 70% of S. aureus showed resistance against ampicillin, oxacillin, and tetracycline and more than 60% of E. coli exhibited resistance against oxacillin and sulfamethoxazole-trimethoprim. Selected antimicrobial resistance genes (mecA, tetK, tetL, tetM, tetA, tetB, tetC, sul1, sul2 and sul3) were identified from S. aureus and E. coli. Surprisingly, 7 (7.61%) S. aureus carried the mecA gene and were confirmed as methicillin-resistant S. aureus (MRSA). The most prevalent resistance genes were tetK 18 (19.57%) and tetL 13 (14.13%) for S. aureus, whereas sul1 16 (47.06%), tetA 12 (35.29%), sul2 11 (32.35%) and tetB 7 (20.59%) were the most common resistance genes in E. coli. Indiscriminate use of antimicrobials and the presence of multidrug-resistant bacteria suggest a potential threat to public health. | 2022 | 35291582 |
| 1283 | 15 | 0.9998 | Antimicrobial Resistance Profiles of Staphylococcus Isolated from Cows with Subclinical Mastitis: Do Strains from the Environment and from Humans Contribute to the Dissemination of Resistance among Bacteria on Dairy Farms in Colombia? Staphylococcus is a very prevalent etiologic agent of bovine mastitis, and antibiotic resistance contributes to the successful colonization and dissemination of these bacteria in different environments and hosts on dairy farms. This study aimed to identify the antimicrobial resistance (AMR) genotypes and phenotypes of Staphylococcus spp. isolates from different sources on dairy farms and their relationship with the use of antibiotics. An antimicrobial susceptibility test was performed on 349 Staphylococcus strains (S. aureus, n = 152; non-aureus staphylococci (NAS), n = 197) isolated from quarter milk samples (QMSs) from cows with subclinical mastitis (176), the teats of cows (116), the milking parlor environment (32), and the nasal cavities of milk workers (25). Resistance and multidrug resistance percentages found for S. aureus and NAS were (S. aureus = 63.2%, NAS = 55.8%) and (S. aureus = 4.6%, NAS = 11.7%), respectively. S. aureus and NAS isolates showed resistance mainly to penicillin (10 IU) (54.1% and 32.4%) and ampicillin (10 mg) (50.3% and 27.0%) drugs. The prevalence of AMR Staphylococcus was higher in environmental samples (81.3%) compared to other sources (52.6-76.0%). In S. aureus isolates, the identification of the blaZ (83.9%), aacAaphD (48.6%), ermC (23.5%), tetK (12.9%), and mecA (12.1%) genes did not entirely agree with the AMR phenotype. We conclude that the use of β-lactam antibiotics influences the expression of AMR in Staphylococcus circulating on dairy farms and that S. aureus isolates from the environment and humans may be reservoirs of AMR for other bacteria on dairy farms. | 2023 | 37998777 |
| 1197 | 16 | 0.9998 | Sink survey to investigate multidrug resistance pattern of common foodborne bacteria from wholesale chicken markets in Dhaka city of Bangladesh. Antimicrobial resistance (AMR) among foodborne bacteria is a well-known public health problem. A sink survey was conducted to determine the AMR pattern of common foodborne bacteria in cloacal swab of broiler chickens and sewage samples from five wholesale chicken markets of Dhaka city in Bangladesh. Bacteria were identified by culture-based and molecular methods, and subjected to antimicrobial susceptibility testing. Resistance genes were identified by multiplex PCR and sequencing. Multidrug resistance (MDR) was observed in 93.2% of E. coli, 100% of Salmonella spp., and 97.2% of S. aureus from cloacal swab samples. For sewage samples, 80% of E. coli, and 100% of Salmonella and S. aureus showed MDR. Noteworthy, 8.3% of S. aureus from cloacal swab samples showed possible extensively drug resistance. Antimicrobial resistance genes (beta-lactamase-blaTEM, blaSHV; quinolone resistance gene-qnrS) were detected in a number of E. coli and Salmonella isolates from cloacal swab and sewage samples. The methicillin resistance gene (mecA) was detected in 47.2% and 25% S. aureus from cloacal swab and sewage samples, respectively. The findings envisage the potential public health risk and environmental health hazard through spillover of common foodborne MDR bacteria. | 2022 | 35752640 |
| 1290 | 17 | 0.9998 | 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 |
| 2673 | 18 | 0.9998 | Geographical and ecological analysis of resistance, coresistance, and coupled resistance to antimicrobials in respiratory pathogenic bacteria in Spain. A multicenter susceptibility surveillance (the S.A.U.C.E. project) including 2,721 Streptococcus pneumoniae, 3,174 Streptococcus pyogenes, and 2,645 Haemophilus influenzae consecutive isolates was carried out in 25 hospitals all over Spain from November 2001 to October 2002 to evaluate the current epidemiology of resistance of the main bacteria involved in community-acquired respiratory tract infections. Susceptibility testing was performed in a single centralized laboratory by a broth microdilution method. The prevalence of resistant S. pneumoniae strains was 0.4% for cefotaxime, 4.4% for amoxicillin and amoxicillin-clavulanic acid, 25.6% for cefuroxime-axetil, 34.5% for erythromycin, clarithromycin, and azithromycin, and 36.0% for cefaclor. Phenotypes of resistance to erythromycin were MLS(B) (macrolide-lincosamide-streptogramin B) in 89.9% (gene ermB) and M (macrolide) in 9.7% of cases (gene mefA). No strain harbored both genes simultaneously. Serotypes 19, 6, 23, 14, and 3 were the most prevalent, accounting for 54.6% of the total isolates. Resistance to macrolides seems to be the most alarming point, since among penicillin-susceptible isolates it reached 15.1% compared to 55.8% among penicillin-resistant strains. Geographically, a number of regions had rates of erythromycin resistance above 40% (even higher in children). Resistance to erythromycin was also high in S. pyogenes isolates: mean regional 33.2%, beta-lactamase-producing H. influenzae were 20%, whereas 4.4% had a beta-lactamase-negative, ampicillin-resistant phenotype. We highlight the importance of different geographical frequencies of coresistance (associations of resistance to different drugs within the same species) and coupled resistance (association of resistance between different species) probably resulting from different local coselective events. | 2005 | 15855520 |
| 1280 | 19 | 0.9998 | Antimicrobial-Resistant Staphylococcus spp. Harbored by Hedgehogs (Erinaceus europaeus) in Central Italy. BACKGROUND/OBJECTIVES: European hedgehogs (Erinaceus europaeus) are present in areas where there is human activity; therefore, they can be a source of pathogens for other animals and humans. METHODS: Eighteen hedgehog carcasses were collected and analyzed for Staphylococcus spp. Isolated strains were typed and analyzed for exfoliative toxins genes and the phenotypic and genotypic characteristics of antimicrobial resistance. RESULTS: A total of 54 strains were isolated and typed as S. aureus, S. xylosus, S. sciuri, S. pseudintermedius, S. simulans, S. chromogenes, S. epidermidis, S. hyicus, and S. lentus. No strains had the eta and etb genes coding for exfoliative toxins. Overall, 39/54 (72.20%) isolates showed phenotypic resistance to at least one antimicrobial and 21/54 (38.80%) showed more than one resistance. The lowest efficacy was observed for erythromycin, with 40/54 (74.08%) strains classified as intermediate and 6/54 (11.11%) classified as resistant. Among the 29 isolates shown to be penicillin-resistant, 11 (37.93%) were oxacillin-resistant, with a minimum inhibitory concentration (MIC). Among the 54 staphylococcal strains, 2 (3.70%) were resistant to vancomycin, both with an MIC value equal to the maximum concentration of the antibiotic tested (256 μg/mL) and 2 (3.70%) had an intermediate resistance profile with an 8 μg/mL MIC value. No strains had the genes vanA and vanB. Two of the 29 (6.90%) penicillin-resistant strains had the blaZ gene; 8 (27.13%) strains had the mecA gene. Overall, 2/54 (3.70%) isolates were classified as extensively drug-resistant (XDR) and 9/54 (16.66%) were classified as multidrug-resistant (MDR). CONCLUSIONS: Hedgehogs can harbor antimicrobial-resistant staphylococci and can be sources of these bacteria for other animals and humans. They can also serve as bioindicators of the pathogens and antimicrobial-resistant bacteria circulating in a given habitat. | 2025 | 40724026 |