Characterization of antibiotic resistance in Escherichia coli isolated from shrimps and their environment. - Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
130501.0000Characterization of antibiotic resistance in Escherichia coli isolated from shrimps and their environment. Antimicrobial resistance in bacteria associated with food and water is a global concern. To survey the risk, 312 Escherichia coli isolates from shrimp farms and markets in Thailand were examined for susceptibility to 10 antimicrobials. The results showed that 17.6% of isolates (55 of 312) were resistant to at least one of the tested drugs, and high resistance rates were observed to tetracycline (14.4%; 45 of 312), ampicillin (8.0%; 25 of 312), and trimethroprim (6.7%; 21 of 312); 29.1% (16 of 55) were multidrug resistant. PCR assay of the tet (A), tet (B), tet (C), tet (D), tet (E), and tet (G) genes detected one or more of these genes in 47 of the 55 resistant isolates. Among these genes, tet (A) (69.1%; 38 of 55) was the most common followed by tet (B) (56.4%; 31 of 55) and tet (C) (3.6%; 2 of 55). The resistant isolates were further investigated for class 1 integrons. Of the 55 resistant isolates, 16 carried class 1 integrons and 7 carried gene cassettes encoding trimethoprim resistance (dfrA12 or dfrA17) and aminoglycosides resistance (aadA2 or aadA5). Two class 1 integrons, In54 (dfrA17-aadA5) and In27 (dfrA12-orfF-aadA2), were found in four and three isolates, respectively. These results indicate a risk of drug-resistant E. coli contamination in shrimp farms and selling places. The occurrence of multidrug-resistant E. coli carrying tet genes and class 1 integrons indicates an urgent need to monitor the emergence of drug-resistant E. coli to control the dissemination of drug-resistant strains and the further spread of resistance genes to other pathogenic bacteria.201425198603
130610.9999Escherichia coli from healthy farm animals: Antimicrobial resistance, resistance genes and mobile genetic elements. The use of antibiotics in agriculture and subsequent environmental pollution are associated with the emergence and spread of multidrug-resistant (MDR) bacteria including Escherichia coli. The aim of this study was to detect antimicrobial resistance, resistance genes and mobile genetic elements of 72 E. coli strains isolated from faeces of healthy farm animals. Disk diffusion test showed resistance to ampicillin (59.7%), tetracycline (48.6%), chloramphenicol (16.7%), cefoperazone and ceftriaxone (13.9%), cefepime and aztreonam (12.5%), norfloxacin and ciprofloxacin (8.3%), levofloxacin (6.9%), gentamicin and amikacin (2.8%) among the studied strains. Antibiotic resistance genes (ARGs) were detected by polymerase chain reaction: the prevalence of blaTEM was the highest (59.7% of all strains), followed by tetA (30.6%), blaCTX-M (11.1%), catA1 (9.7%), less than 5% strains contained blaSHV, cmlA, floR, qnrB, qnrS, tetM. 26.4% of E. coli strains had a MDR phenotype. MDR E. coli more often contained class 1 integrons, bacteriophages, conjugative F-like plasmids, than non-MDR strains. ARGs were successfully transferred from faecal E. coli strains into the E. coli Nissle 1917 N4i strain by conjugation. Conjugation frequencies varied from (1.0 ± 0.1) * 10-5 to (7.9 ± 2.6) * 10-4 per recipient. Monitoring mobile genetic elements of E. coli for antibiotic resistance is important for farm animal health, as well as for public health and food safety.202439259602
137820.9999Antimicrobial resistance and resistance genes in Escherichia coli strains isolated from commercial fish and seafood. The purpose of this study was to investigate the antimicrobial resistance and to characterize the implicated genes in Escherichia coli isolated from commercial fish and seafood. Fish and seafood samples (n=2663) were collected from wholesale and retail markets in Seoul, Korea between 2005 and 2008. A total of 179 E. coli isolates (6.7%) from those samples were tested for resistance to a range of antimicrobial agents. High rates of resistance to the following drugs were observed: tetracycline (30.7%), streptomycin (12.8%), cephalothin (11.7%), ampicillin (6.7%) and ticarcillin (6.1%). No resistances to amikacin, amoxicillin/clavulanic acid and cefoxitin were observed. Seventy out of 179 isolates which were resistant to one or more drugs were investigated by PCR for the presence of 3 classes of antimicrobial resistance genes (tetracycline, aminoglycosides and beta-lactams), class 1, 2 and 3 integrons. Gene cassettes of classes 1 and 2 integrons were further characterized by amplicon sequencing. The tetracycline resistance genes tetB and tetD were found in 29 (41.4%) isolates and 14 (20%) isolates, respectively. The beta-lactam resistance gene, bla(TEM) was found in 15 (21.4%) isolates. The aminoglycoside resistance gene, aadA was found in 18 (25.7%) isolates. Class 1 integron was detected in 41.4% (n=29) of the isolates, while only 2.9% (n=2) of the isolates were positive for the presence of class 2 integron. Two different gene cassettes arrangements were identified in class 1 integron-positive isolates: dfrA12-aadA2 (1.8 kb, five isolates) and aadB-aadA2 (1.6 kb, four isolates). One isolate containing class 2 integron presented the dfrA1-sat-aadA1 gene cassette array. These data suggest that commercial fish and seafood may act as the reservoir for multi-resistant bacteria and facilitate the dissemination of the resistance genes.201222071288
115630.9999Detection of qnr, aac(6')-Ib-cr and qepA genes in Escherichia coli isolated from cooked meat products in Henan, China. Antimicrobial resistance in Escherichia coli has increased in recent years in China. Antimicrobial resistant isolates and resistance genes of E. coli can be transferred to humans through the food chain and this presents a public health risk. However, few studies have investigated the prevalence of antimicrobial resistance-encoding genes in E. coli isolated from food samples in China. The aim of this study was to investigate the presence of quinolone resistance genes (QRGs) and extended-spectrum β-lactamases (ESBLs) in E. coli isolated from cooked meat products in Henan, China. A total of 75 E. coli isolates (12.1%) were detected from 620 samples. High rates of resistance to the following drugs were observed: tetracycline (56.0%), trimethoprim/sulfamethoxazole (41.3%), streptomycin (29.3%), ampicillin (26.7%) and nalidixic acid (14.7%). Of the 75 isolates, QRGs were present in 10 isolates (13.3%), with qnr and aac(6')-Ib-cr detected alone or in combination in five (6.7%) and eight isolates (10.7%). The qnr genes detected in this study included qnrS (n=3) and qnrA (n=2). The qepA gene was absent among these isolates. Three types of β-lactamase genes were identified in the five ESBL-producing E. coli isolates: blaCTX-M-1, blaCTX-M-9, and blaTEM-1. The qnrS gene was found to be co-transferred with blaCTX-M-1 and blaTEM-1 in one isolate. Our data suggest that cooked meat products may act as reservoirs for multi-resistant bacteria and facilitate the dissemination of antimicrobial resistance genes.201425036771
137740.9999Characterization and Horizontal Transfer of Antimicrobial Resistance Genes and Integrons in Bacteria Isolated from Cooked Meat Products in China. The aim of this study was to investigate antimicrobial resistance and the presence and transferability of corresponding resistance genes and integrons in bacteria isolated from cooked meat samples in the People's Republic of China. A total of 150 isolates (22 species belonging to 15 genera) were isolated from 49 samples. Resistance of these isolates to antimicrobials was commonly observed; 42.7, 36.0, and 25.3% of the isolates were resistant to tetracycline, streptomycin, and ampicillin, respectively. Multidrug resistance was observed in 41 (27.3%) of the isolates. Sixteen resistance genes, i.e., bla(TEM-1) and bla(CTX-M-14) (β-lactams), aac(3)-IIa (gentamicin), strA and strB (streptomycin), qnrB and qnrS (fluoroquinolone), sul1, sul2, and sul3 (sulfamethoxazole), cat1 and cat2 (chloramphenicol), and tetM, tetA, tetS, and tetB (tetracycline), were found in 54 isolates. One isolate of Pseudomonas putida carried qnrB, and sequence analysis of the PCR product revealed 96% identity to qnrB2. The qnr genes were found coresiding and were cotransferred with bla genes in two isolates. Twelve isolates were positive for the class 1 integrase gene, and four isolates carried the class 2 integrase gene. However, no class 3 integrase gene was detected. One isolate of Proteus mirabilis carried dfrA32-ereA-aadA2, and this unusual array could be transferred to Escherichia coli. Nonclassic class 1 integrons lacking qacEΔ1 and sul1 genes were found in 2 of the 12 intI1-positive isolates. Our results revealed the presence of multidrug-resistant bacteria in cooked meats and the presence and transferability of resistance genes in some isolates, suggesting that cooked meat products may act as reservoirs of drug-resistant bacteria and may facilitate the spread of resistance genes.201729148877
115550.9999Prevalence and antimicrobial resistance profiles of Escherichia coli isolated from free-range pigs. INTRODUCTION: Numerous studies about antimicrobial resistant Escherichia coli (E. coli) of animal origins have been conducted around the world, most of them focus on bacteria from animals raised in intensive breeding farms, but systematic studies on antimicrobial resistance in E. coli of free range animals are still lacking. METHODOLOGY: This study aimed to investigate the prevalence and antimicrobial resistance profiles of E. coli from free-range pigs in Laiwu mountainous areas, eastern China. RESULTS: Among 123 fecal samples, 123 non-duplicate E. coli were obtained with an isolation rate of 100.0％ (123/123). These E. coli showed the highest resistance rate to tetracycline (77/123, 62.6％), but all were sensitive to amoxicillin/clavulanic acid. Thirty-eight E. coli (38/123, 30.9％) showed multidrug resistance (MDR). Among 123 E. coli isolates, only 39 carried antimicrobial resistant genes detected in this study. Of these 39 isolates, blaTEM-1, blaCTX-M-14, blaCTX-M-15, qnrB, qnrD, qnrS1, floR and cfr genes were detected in 13, 9, 4, 7, 10, 7, 20, and 7 isolates, respectively. blaTEM-1 and blaCTX-M-14 genes were concomitantly detected in 6 isolates, and blaTEM, qnrB, qnrS and qnrD genes were concomitantly detected in 7 isolates. CONCLUSIONS: Free-ranging pigs may be regarded as a potential reservoir for antibiotic resistant genes.201731085827
202560.9999Diverse Gene Cassette Arrays Prevail in Commensal Escherichia coli From Intensive Farming Swine in Four Provinces of China. Multiple-drug resistance bacteria containing antimicrobial resistance genes (ARGs) are a concern for public health. Integrons are bacterial genetic elements that can capture, rearrange, and express mobile gene cassettes responsible for the spread of ARGs. Few studies link genotype and phenotype of swine-related ARGs in the context of mobile gene cassette arrays among commensal Escherichia coli (E. coli) in nonclinical livestock isolates from intensive farms. In the present study, a total of 264 isolates were obtained from 330 rectal swabs to determine the prevalence and characteristics of antibiotic-resistant gene being carried by commensal E. coli in the healthy swine from four intensive farms at Anhui, Hebei, Shanxi, and Shaanxi, in China. Antimicrobial resistance phenotypes of the recovered isolates were determined for 19 antimicrobials. The E. coli isolates were commonly nonsusceptible to doxycycline (75.8%), tetracycline (73.5%), sulfamethoxazole-trimethoprim (71.6%), amoxicillin (68.2%), sulfasalazine (67.1%), ampicillin (58.0%), florfenicol (56.1%), and streptomycin (53.0%), but all isolates were susceptible to imipenem (100%). Isolates [184 (69.7%)] exhibited multiple drug resistance with 11 patterns. Moreover, 197 isolates (74.6%) were detected carrying the integron-integrase gene (intI1) of class 1 integrons. A higher incidence of antimicrobial resistance was observed in the intI1-positive E. coli isolates than in the intI1-negative E. coli isolates. Furthermore, there were 17 kinds of gene cassette arrays in the 70 integrons as detected by sequencing amplicons of variable regions, with 66 isolates (94.3%) expressing their gene cassettes encoding for multiple drug resistance phenotypes for streptomycin, neomycin, gentamicin, kanamycin, amikacin, sulfamethoxazole-trimethoprim, sulfasalazine, and florfenicol. Notably, due to harboring multiple, hybrid, and recombination cassettes, complex cassette arrays were attributed to multiple drug resistance patterns than simple arrays. In conclusion, we demonstrated that the prevalence of multiple drug resistance and the incidence of class 1 integrons were 69.7 and 74.6% in commensal E. coli isolated from healthy swine, which were lower in frequency than that previously reported in China.202033154738
130470.9999Serovar and sequence type distribution and phenotypic and genotypic antimicrobial resistance of Salmonella originating from pet animals in Chongqing, China. A total of 334 Salmonella isolates were recovered from 6,223 pet rectal samples collected at 50 pet clinics, 42 pet shops, 7 residential areas, and 4 plazas. Forty serovars were identified that included all strains except for one isolate that did not cluster via self-agglutination, with Salmonella Typhimurium monophasic variant, Salmonella Kentucky, Salmonella Enteritidis, Salmonella Pomona, and Salmonella Give being the predominant serovars. Fifty-one sequence types were identified among the isolates, and ST198, ST11, ST19, ST451, ST34, and ST155 were the most common. The top four dominant antimicrobials to which isolates were resistant were sulfisoxazole, ampicillin, doxycycline, and tetracycline, and 217 isolates exhibited multidrug resistance. The prevalence of β-lactamase genes in Salmonella isolates was 59.6%, and among these isolates, 185 harbored bla(TEM), followed by bla(CTX-M) (66) and bla(OXA) (10). Moreover, six PMQR genes, namely, including qnrA (4.8%), qnrB (4.2%), qnrD (0.9%), qnrS (18.9%), aac(6')-Ib-cr (16.5%), and oqxB (1.5%), were detected. QRDR mutations (76.6%) were very common in Salmonella isolates, with the most frequent mutation in parC (T57S) (47.3%). Furthermore, we detected six tetracycline resistance genes in 176 isolates, namely, tet(A) (39.5%), tet(B) (8.1%), tet(M) (7.7%), tet(D) (5.4%), tet(J) (3.3%), and tet(C) (1.8%), and three sulfonamide resistance genes in 303 isolates, namely, sul1 (84.4%), sul2 (31.1%), and sul3 (4.2%). Finally, we found 86 isolates simultaneously harboring four types of resistance genes that cotransferred 2-7 resistance genes to recipient bacteria. The frequent occurrence of antimicrobial resistance, particularly in dogs and cats, suggests that antibiotic misuse may be driving multidrug-resistant Salmonella among pets.IMPORTANCEPet-associated human salmonellosis has been reported for many years, and antimicrobial resistance in pet-associated Salmonella has become a serious public health problem and has attracted increasing attention. There are no reports of Salmonella from pets and their antimicrobial resistance in Chongqing, China. In this study, we investigated the prevalence, serovar diversity, sequence types, and antimicrobial resistance of Salmonella strains isolated from pet fecal samples in Chongqing. In addition, β-lactamase, QRDR, PMQR, tetracycline and sulfonamide resistance genes, and mutations in QRDRs in Salmonella isolates were examined. Our findings demonstrated the diversity of serovars and sequence types of Salmonella isolates. The isolates were widely resistant to antimicrobials, notably with a high proportion of multidrug-resistant strains, which highlights the potential direct or indirect transmission of multidrug-resistant Salmonella from pets to humans. Furthermore, resistance genes were widely prevalent in the isolates, and most of the resistance genes were spread horizontally between strains.202438757951
137680.9998Incidence of class 1 integron and other antibiotic resistance determinants in Aeromonas spp. from rainbow trout farms in Australia. There is limited information on antibiotic resistance determinants present in bacteria of aquaculture origin in Australia. The presence of integron and other resistance determinants was investigated in 90 Aeromonas isolates derived from nine freshwater trout farms in Victoria (Australia). Polymerase chain reaction was carried out for the detection of integrase genes Int1, Int2 and Int3, gene cassette array, integron-associated aadA, sul1 and qac1 genes, streptomycin resistance genes strA-strB, β-lactamase resistance genes bla(TEM) and bla(SHV) , and tetracycline resistance genes tetA-E and tetM. Clonal analysis was performed by pulsed-field gel electrophoresis (PFGE). Class 1 integrons were detected in 28/90 (31%) and class 2 and class 3 in none of the strains, aadA gene in 19/27 (70%) streptomycin-resistant strains, sul1 in 13/15 (86.7%) sulphonamide-resistant strains and qac1 gene in 8/28 (28.6%) integron-bearing strains. Five strains from two different farms carried gene cassettes of 1000 bp each containing the aadA2 gene and PFGE analysis revealed genetic relatedness. tetC was detected in all and tetA in 9/18 (50%) tetracycline-resistant strains. The strA-strB, bla(TEM) or bla(SHV) genes were not detected in any of the strains. Aeromonas spp. carrying integrons and other resistance genes are present in farm-raised fish and sediments even though no antibiotics were licensed for use in Australian aquaculture at the time of the study.201121762170
115290.9998Gut Commensal Escherichia coli, a High-Risk Reservoir of Transferable Plasmid-Mediated Antimicrobial Resistance Traits. BACKGROUND: Escherichia coli (E. coli), the main human gut microorganism, is one of the evolved superbugs because of acquiring antimicrobial resistance (AMR) determinants via horizontal gene transfer (HGT). PURPOSE: This study aimed to screen isolates of gut commensal E. coli from healthy adult individuals for antimicrobial susceptibility and plasmid-mediated AMR encoding genes. METHODS: Gut commensal E. coli bacteria were isolated from fecal samples that were taken from healthy adult individuals and investigated phenotypically for their antimicrobial susceptibility against diverse classes of antimicrobials using the Kirby Bauer disc method. PCR-based molecular assays were carried out to detect diverse plasmid-carried AMR encoding genes and virulence genes of different E. coli pathotypes (eaeA, stx, ipaH, est, elt, aggR and pCVD432). The examined AMR genes were β-lactam resistance encoding genes (bla (CTX-M1), bla (TEM), bla (CMY-2)), tetracycline resistance encoding genes (tetA, tetB), sulfonamides resistance encoding genes (sul1, sulII), aminoglycoside resistance encoding genes (aac(3)-II, aac(6')-Ib-cr) and quinolones resistance encoding genes (qnrA, qnrB, qnrS). RESULTS: PCR results revealed the absence of pathotypes genes in 56 isolates that were considered gut commensal isolates. E. coli isolates showed high resistance rates against tested antimicrobial agents belonging to both β-lactams and sulfonamides (42/56, 75%) followed by quinolones (35/56, 62.5%), tetracyclines (31/56, 55.4%), while the lowest resistance rate was to aminoglycosides (24/56, 42.9%). Antimicrobial susceptibility profiles revealed that 64.3% of isolates were multidrug-resistant (MDR). High prevalence frequencies of plasmid-carried AMR genes were detected including bla (TEM) (64%) sulI (60.7%), qnrA (51.8%), aac(3)-II (37.5%), and tetA (46.4%). All isolates harbored more than one gene with the most frequent genetic profile among isolates was bla (TEM)-bla (CTX-M1-like)-qnrA-qnrB-tetA-sulI. CONCLUSION: Results are significant in the evaluation of plasmid-carried AMR genes in the human gut commensal E. coli, suggesting a potential human health risk and the necessity of strict regulation of the use of antibiotics in Egypt. Commensal E. coli bacteria may constitute a potential reservoir of AMR genes that can be transferred to other bacterial species.202235321080
2024100.9998Research Note: Longitudinal monitoring of chicken houses in a commercial layer farm for antimicrobial resistance in Escherichia coli with special reference to plasmid-mediated quinolone resistance. Plasmid-mediated quinolone resistance (PMQR) genes located on conjugative plasmids can be transferred to other bacteria in the absence of antimicrobial selective pressure. To elucidate the prevalence of resistance, including PMQR in an egg-producing commercial layer farm in western Japan where no antimicrobials were used, minimum inhibitory concentrations (MIC) for a total of 375 Escherichia coli isolates obtained from chicken houses in the farm between 2012 and 2017 were determined using the agar dilution methods. Eighty-seven isolates resistant to oxytetracycline (OTC) accounted for 23.0% of the tested isolates, followed by isolates resistant to dihydrostreptomycin (DSM) (18.4%), sulfisoxazole (18.1%), ampicillin (AMP) (14.4%), trimethoprim (TMP) (14.4%), and nalidixic acid (10.1%). The prevalence rate of multidrug-resistant (MDR) isolates-which are resistant to 3 or more antimicrobial classes, including β-lactams, aminoglycosides, quinolones, folate pathway inhibitors, tetracyclines, and phenicols-was inversely related to the age of chickens at the time of bacterial examination. Probably, the prevalence of MDR isolates in layer chickens may have decreased with age owing to the absence of selective pressure. Furthermore, 45 isolates exhibiting enrofloxacin MICs of more than 0.25 μg/mL were examined for PMQR genes. The transfer of PMQR genes was tested by conjugation analysis. Southern blot analysis of genomic DNA revealed that the qnrS1 (5 isolates), qnrS2 (1 isolate), and qnrS13 genes (1 isolate) were located on plasmids with sizes ranging from approximately 60 to 120 kpb. In 1 of the 5 qnrS1-positive isolates and in an isolate with qnrS13, the qnrS genes were transferred to recipient strains. The plasmid harboring the qnrS1 gene was typed as IncF by PCR-based replicon typing. On this plasmid, the bla(TEM), aadA, tetA, and dfrA1 genes responsible for resistance to AMP, DSM, OTC, and TMP, respectively, were detected. The tetA gene was detected in the plasmid harboring the qnrS13 gene, which was typed as IncI1. These results suggest that despite the low prevalence of quinolone resistance in this farm, various PMQR genes, located on diverse plasmids, exist.202032036966
1312110.9998Antimicrobial resistance profiles among Escherichia coli strains isolated from commercial and cooked foods. A total of 4330 food samples of which microbiological standard for Escherichia coli is negative in Korea were determined for the frequency of E. coli. Ninety six samples (2.2%) were positive for E. coli. Detection rate of E. coli varied significantly by food type and ranged from 0.3% to 10.9%. Seasoned raw meat (yukhoe) and cold bean-soup had the highest prevalence for E. coli (10.9%) followed by gimbap (5.2%), meat broth for cold noodle (2.9%) and sprout (2.1%). E. coli isolates (n=96) were investigated for their phenotypic and genotypic antimicrobial resistance patterns. Seventeen E. coli isolates (17.7%) were resistant to one or more antimicrobial agents tested. High rates of resistance to the following drugs were observed: tetracycline (15.6%), streptomycin (12.5%), ampicillin (10.4%), nalidixic acid (9.4%) and ticarcillin (9.4%). All ampicillin resistant isolates were screened for extended-spectrum β-lactamase (ESBL) production by the combination disk test. None of the E. coli isolates produced ESBLs. Seventeen out of 96 E. coli isolates which were resistant to at least one antibiotic were investigated by PCR for the presence of 3 classes of antimicrobial resistance genes (tetracycline, aminoglycosides and beta-lactams). The tetracycline resistance genes tetA and tetB were found in 7 and 5 isolates, respectively. The aminoglycoside resistance genes, strA/B, aphA1, aadA and aac(3)-IV were found in 9, 5, 2 and 2 isolates, respectively. The beta-lactam resistance gene, bla(TEM) was found in 7 isolates. Results of this study show that 13 E. coli isolates were multidrug resistant (to three or more antibiotics) and 12 isolates carried at least one antimicrobial resistance gene. These isolates can act as the reservoir for antimicrobial resistance genes and facilitate the dissemination of these genes to other pathogenic and commensal bacteria. Adequate intervention to reduce microbial contamination of these foods is strongly recommended.201223107506
1154120.9998Migratory wild birds carrying multidrug-resistant Escherichia coli as potential transmitters of antimicrobial resistance in China. Migratory birds play an important role in the spread of multidrug-resistant (MDR) bacteria. To investigate the prevalence of MDR Escherichia coli in migratory birds in China and potential relationships with the environment, a total of 1387 samples (fecal samples, cloacal swabs, or throat swabs) were collected from migratory birds from three different river basins in China. The collected samples were processed and subjected to bacteriological examinations. Antimicrobial susceptibility testing of the recovered isolates was performed using the E-test for the detection of minimum inhibitory concentrations (MICs). Some antibiotic resistance genes were detected and the PCR products were confirmed by sequencing. In total, 478 (34.7%) E. coli isolates were recovered. The results showed that the drug-resistant E. coli isolates were highly resistant to β-lactams (43.7%) and tetracycline (22.6%), and 73 (15.3%) were MDR, including eight that were extended spectrum β-lactamase-positive. The retrieved strains harbored the blaCTX-M, blaTEM-1, tet(A), tet(B), tet(M), sul1, sul2, sul3, cmlA, floR, and intI1 genes with a prevalence of 5.9%, 36.4%, 80.5%, 11.9%, 6.8%, 6.8%, 47.5%, 12.7%, 50.8%, 37.3%, and 61.0%, respectively. The drug resistance rate of the isolates from southern China was higher than those from northern China. The E. coli samples collected for migratory birds in the Pearl River Basin had the highest proportion (46.7%) MDR isolates. Furthermore, MDR bacteria carried by migratory birds were closely related to the antibiotic content in the basin, which confirms that MDR bacteria carried by migratory birds are likely acquired from the environment. This study also confirmed that migratory birds are potential transmitters of MDR bacteria, demonstrating the need to reduce the use and emission of antibiotics and further in-depth studies on the mechanisms underlying drug resistance of bacteria.202134910771
2023130.9998Class 1 and class 2 integrons and plasmid-mediated antibiotic resistance in coliforms isolated from ten rivers in northern Turkey. We aimed to determine the molecular mechanisms of antibiotic resistance in coliforms isolated from ten rivers in northern region of Turkey. A total of 183 isolates were tested for antimicrobial susceptibility by disk diffusion and agar dilution methods. Resistance to ampicillin, streptomycin, trimethoprim, tetracycline, and chloramphenicol was detected in 58%, 51.9%, 24%, 28.4%, and 12.5%, respectively. Twelve (6.5%) phylogenetically distant organisms were detected to harbor self-transmissible plasmids ranging 52 to >147 kb in sizes. Resistances to ampicillin, tetracycline, trimethoprim, streptomycin, and nalidixic acid were commonly transferable traits. Transferable nalidixic acid-resistant strains harbored qnrS gene, which was the first report of plasmid-mediated quinolone resistance in bacteria of environmental origin in Turkey. Fourteen and five coliforms harbored class 1 and class 2 integrons, respectively, and some of them were located on transferable plasmids. Sequence analyses of variable regions of the class 1 and 2 integrons harbored various gene cassettes, dfrA1, dfr2d, dfrA7, dfrA16, dfrA17, aadA1, aadA5, bla(oxA-30), and sat1. A gene cassette array, dfrA16 has been demonstrated for the first time in a Citrobacter koseri isolate. Class 1 and class 2-bearing strains were clustered in different groups by BOX-PCR fingerprinting. Rivers in the northern Turkey may act as receptacle for the multi-drug resistant enterobacteria and can serve as reservoirs of the antimicrobial resistance determinants in the environment. The actual risk to public health is the transfer of resistance genes from the environmental bacteria to human pathogens.200919229487
1143140.9998Antimicrobial Resistance and Virulence Profiles of mcr-1-Positive Escherichia coli Isolated from Swine Farms in Heilongjiang Province of China. ABSTRACT: The emergence and global distribution of the mcr-1 gene for colistin resistance have become a public concern because of threats to the role of colistin as the last line of defense against some bacteria. Because of the prevalence of mcr-1-positive Escherichia coli isolates in food animals, production of these animals has been regarded as one of the major sources of amplification and spread of mcr-1. In this study, 249 E. coli isolates were recovered from 300 fecal samples collected from swine farms in Heilongjiang Province, People's Republic of China. Susceptibility testing revealed that 186 (74.70%) of these isolates were colistin resistant, and 86 were positive for mcr-1. The mcr-1-positive isolates had extensive antimicrobial resistance profiles and additional resistance genes, including blaTEM, blaCTX-M, aac3-IV, tet(A), floR, sul1, sul2, sul3, and oqxAB. No mutations in genes pmrAB and mgrB were associated with colistin resistance. Phylogenetic group analysis revealed that the mcr-1-positive E. coli isolates belonged to groups A (52.33% of isolates), B1 (33.72%), B2 (5.81%), and D (8.14%). The prevalence of the virulence-associated genes iutA, iroN, fimH, vat, ompA, and traT was moderate. Seven mcr-1-positive isolates were identified as extraintestinal pathogenic. Among 20 mcr-1-positive E. coli isolates, multilocus sequence typing revealed that sequence type 10 was the most common (five isolates). The conjugation assays revealed that the majority of mcr-1 genes were transferable at frequencies of 7.05 × 10-7 to 7.57 × 10-4. The results of this study indicate the need for monitoring and minimizing the further dissemination of mcr-1 among E. coli isolates in food animals, particularly swine.202032730609
1368150.9998Prevalence and characterisation of antimicrobial resistance genes and class 1 and 2 integrons in multiresistant Escherichia coli isolated from poultry production. A global increase in the populations of drug resistant bacteria exerts negative effects on animal production and human health. Our study has been focused on the assessment of resistance determinants in relation to phenotypic resistance of the 74 commensal E. coli isolates present in different ecological environments. The samples were collected from poultry litter, feces, and neck skin. Among the microorganisms isolated from the poultry litter (group A), the highest resistance was noted against AMP and DOX (100%). In the E. coli extracts from the cloacal swabs (group B), the highest resistance was observed against AMP (100%) and CIP (92%). The meat samples (group C) were characterized by resistance to AMP (100%) and STX (94.7%). Genes encoding resistance to β-lactams (bla(TEM), bla(CTX-M)), fluoroquinolones (qnrA, qnrB, qnrS), aminoglycosides (strA-strB, aphA1, aac(3)-II), sulfonamides (sul1, sul2, sul3), trimethoprim (dfr1, dfr5, dfr7/17) and tetracyclines (tetA, tetB) were detected in the studied bacterial isolates. The presence of class 1 and 2 integrons was confirmed in 75% of the MDR E. coli isolates (plasmid DNA), of which 60% contained class 1 integrons, 15% contained class 2 integrons, and 11.7% carried integrons of both classes. Thus, it may be concluded that integrons are the common mediators of antimicrobial resistance among commensal multidrug resistant Escherichia coli at important stages of poultry production.202235410349
1149160.9998Antimicrobial resistance, Extended-Spectrum β-Lactamase production and virulence genes in Salmonella enterica and Escherichia coli isolates from estuarine environment. The impact of antimicrobial resistance (AMR) on global public health has been widely documented. AMR in the environment poses a serious threat to both human and animal health but is frequently overlooked. This study aimed to characterize the association between phenotype and genotype of AMR, virulence genes and Extended-Spectrum β-Lactamase (ESBL) production from estuarine environment. The Salmonella (n = 126) and E. coli (n = 409) were isolated from oysters and estuarine water in Thailand. The isolates of Salmonella (96.9%) and E. coli (91.4%) showed resistance to at least one antimicrobial agent. Multidrug resistance (MDR) was 40.1% of Salmonella and 23.0% of E. coli. Resistance to sulfamethoxazole was most common in Salmonella (95.2%) and E. coli (77.8%). The common resistance genes found in Salmonella were sul3 (14.3%), followed by blaTEM (11.9%), and cmlA (11.9%), while most E. coli were blaTEM (31.5%) and tetA (25.4%). The ESBL production was detected in Salmonella (1.6%, n = 2) of which one isolate was positive to blaTEM-1. Eight E. coli isolates (2.0%) were ESBL producers, of which three isolates carried blaCTX-M-55 and one isolate was blaTEM-1. Predominant virulence genes identified in Salmonella were invA (77.0%), stn (77.0%), and fimA (69.0%), while those in E. coli isolates were stx1 (17.8%), lt (11.7%), and stx2 (1.2%). Logistic regression models showed the statistical association between resistance phenotype, virulence genes and ESBL production (p < 0.05). The findings highlighted that estuarine environment were potential hotspots of resistance. One Health should be implemented to prevent AMR bacteria spreading.202337115770
1361170.9998Multi-drug resistance and diversity of mobile genetic elements in Escherichia coli isolated from migratory bird in Poyang Lake. With the spread of antibiotic resistance genes such as blaCTX-M-2, dfrA1 and blaNDM-1, the problem of drug resistance in E. coli is becoming increasingly serious [1]. This study aimed to identify integrons genes and MGEs in E. coli isolated from migratory birds' feces at Poyang Lake, Jiangxi Province, focusing on their role in antimicrobial resistance (AMR). The 114 isolated E. coli strains were tested by standard disk diffusion method and genetic testing method. Results showed 64.04 % (73/114) of isolates were multi-drug resistance (MDR), mainly resistant to 3-6 antibiotics. Common resistances included neomycin (50 %) and streptomycin (48.25 %). We detected 21 mobile genetic elements, including IS903 (92.11 %), traA (72.81 %), ISCR3 (64.91 %), and ISpa7 (50 %). These elements were present in all isolates, forming 112 combinations. Significant differences in resistance rates were found between class I integron-positive and negative strains for doxycycline, tetracycline, bacitracin, and streptomycin (P < 0.01), and for neomycin (P < 0.05). Class II integron-positive bacteria showed higher resistance to doxycycline (P < 0.01) and ceftizoxime (P < 0.05). No significant differences were observed for class III integron-positive strains. This study underscores the prevalence of multidrug-resistant and the diversity of mobile genetic elements in E. coli, emphasizing the need for continuous monitoring.202540651621
1274180.9998Characterization of antimicrobial resistance among Escherichia coli isolates from chickens in China between 2001 and 2006. Escherichia coli is a common commensal bacterium and is regarded as a good indicator organism for antimicrobial resistance for a wide range of bacteria in the community and on farms. Antimicrobial resistance of E. coli isolated from chickens from 49 farms in China between 2001 and 2006 was studied. A total of 536 E. coli isolates were collected, and minimal inhibitory concentrations (MICs) of eight antimicrobials were determined by the broth microdilution method. Isolates exhibited high levels of resistance to ampicillin (80.2%), doxycycline (75.0%) and enrofloxacin (67.5%). Relatively lower resistance rates to cephalothin (32.8%), cefazolin (17.0%) and amikacin (6.5%) were observed. Strains were comparatively susceptible to colistin (MIC(50) = 1 microg mL(-1)). A marked increase in isolates with elevated MICs for florfenicol was observed over the study period. Therefore, five resistance genes leading to the dissemination of phenicol resistance in the isolates (n = 113) with florfenicol MICs > or = 32 microg mL(-1) were analyzed. The gene floR was the most prevalent resistance gene and was detected in 92% of the 113 isolates, followed by the cmlA (53%), catA1 (23%) and catA2 (10%) genes. catA3 was not detected in these isolates. Eight isolates with florfenicol MICs = 32 microg mL(-1) and one with MIC = 64 microg mL(-1) were negative for the floR gene.200818680521
968190.9998Molecular analysis of antimicrobial resistance in gram-negative bacteria isolated from fish farms in Egypt. As little is known about antimicrobial resistance genes in fish farms, this study was conducted to monitor the incidence and prevalence of a wide range of antimicrobial resistance genes in Gram-negative bacteria isolated from water samples taken from fish farms in the northern part of Egypt. Ninety-one out of two hundred seventy-four (33.2%) non-repetitive isolates of Gram-negative bacteria showed multidrug resistance phenotypes and harbored at least one antimicrobial resistance gene. PCR and DNA sequencing results showed that 72 (26.3%) isolates contain tetracycline resistance genes and 19 (6.9%) isolates were positive for class 1 integrons with 12 different gene cassettes. The beta-lactamase-encoding genes were identified in 14 (5.1%) isolates. The plasmid-mediated quinolone resistance genes, qnr and aac(6')-Ib-cr, were identified in 16 (5.8%) and 3 (1.1%) isolates, respectively. Finally, the florphenicol resistance gene, floR, was identified in four (1.5%) isolates. To the best of our knowledge, this is the first report for molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from fish farms in Africa.201020145377