Department of Pathology, Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet, 3100, Bangladesh.
ABEx Bio-Research Center, Dhaka, Bangladesh.
Sci Rep. 2020 Dec 15;10(1):21999. doi: 10.1038/s41598-020-78367-2.
Antibiotic-resistant Escherichia coli (E. coli) are common in retail poultry products. In this study, we aimed to isolate and characterize multidrug resistant (MDR) E. coli in raw chicken meat samples collected from poultry shops in Sylhet division, Bangladesh, as well as to determine correlation between resistance phenotype and genotype. A total of 600 chicken meat swabs (divided equally between broiler and layer farms, n = 300 each) were collected and the isolates identified as E. coli (n = 381) were selected. Disc diffusion antimicrobial susceptibility assay showed resistance of these isolates to ampicillin, erythromycin, tetracycline, streptomycin, trimethoprim-sulfamethoxazole, chloramphenicol, and gentamicin. Polymerase chain reaction (PCR) identified several antibiotic resistance genes (ARGs) in our isolates. Among these ARGs, the prevalence of tetA (for tetracycline) was the highest (72.58%) in broiler chicken isolates, followed by sul1 (for sulfonamide; 44.16%), aadA1 (for streptomycin; 33.50%), ereA (for erythromycin; 27.41%), aac-3-IV (for gentamicin; 25.38%), and the two genes cmlA (24.87%) and catA1 (8.63%) for chloramphenicol. On the other hand, the respective prevalence in layer chicken isolates were 82.06%, 47.83%, 35.87%, 35.33%, 23.91%, 19.02%, and 5.43%. Furthermore, 49.23% of the isolates from broiler chicken were MDR, with the presence of multiple antibiotic resistance genes, including 3 (40.11%) and 4 (9.13%) genes. On the other hand, 51.09% of layer chicken E. coli isolates were MDR, with 3, 4 or 5 ARGs detected in 36.41%, 14.13%, and 0.54% of the isolates, respectively. We also found that 12.8% of broiler chicken E. coli isolates and 7.61% of layer chicken isolates carried genes coding for extended-spectrum SHV beta-lactamases. Lastly, we report the presence of the AmpC beta-lactamase producing gene (CITM) in 4.56% and 3.26% of broiler and layer chicken E. coli isolates, respectively. We found significant correlations between most of the antimicrobial resistant phenotypes and genotypes observed among the investigated E. coli isolates. Our findings highlight the need for the prudent use of antimicrobials in chickens to minimize the development of antibiotic-resistant bacterial strains.
食源性耐多药大肠杆菌的研究进展
食源性耐多药大肠杆菌（E. coli）在零售禽类产品中很常见。本研究旨在从孟加拉国锡尔赫特地区的家禽店采集的生鸡肉样本中分离和鉴定多药耐药（MDR）大肠杆菌，并确定耐药表型与基因型之间的相关性。共采集了 600 份鸡肉拭子（肉鸡和蛋鸡农场各 300 份），并从中分离出 381 株大肠杆菌。药敏试验结果显示，这些分离株对氨苄西林、红霉素、四环素、链霉素、复方磺胺甲噁唑、氯霉素和庆大霉素均有耐药性。聚合酶链反应（PCR）鉴定出我们的分离株存在多种抗生素耐药基因（ARGs）。在这些 ARGs 中，tetA（用于四环素）在肉鸡分离株中的检出率最高（72.58%），其次是 sul1（用于磺胺类药物；44.16%）、aadA1（用于链霉素；33.50%）、ereA（用于红霉素；27.41%）、aac-3-IV（用于庆大霉素；25.38%）和 cmlA（24.87%）和 catA1（用于氯霉素；8.63%）。另一方面，蛋鸡分离株的相应检出率分别为 82.06%、47.83%、35.87%、35.33%、23.91%、19.02%和 5.43%。此外，49.23%的肉鸡大肠杆菌分离株为多药耐药株，存在多种抗生素耐药基因，包括 3 种（40.11%）和 4 种（9.13%）基因。另一方面，51.09%的蛋鸡大肠杆菌分离株为多药耐药株，在 36.41%、14.13%和 0.54%的分离株中分别检测到 3、4 或 5 种 ARGs。我们还发现，12.8%的肉鸡大肠杆菌分离株和 7.61%的蛋鸡分离株携带编码超广谱 SHV β-内酰胺酶的基因。最后，我们报告了在 4.56%和 3.26%的肉鸡和蛋鸡大肠杆菌分离株中存在 AmpC 型β-内酰胺酶产生基因（CITM）。我们发现，在所研究的大肠杆菌分离株中，大多数观察到的抗菌药物耐药表型和基因型之间存在显著相关性。我们的研究结果强调了在养鸡过程中谨慎使用抗生素的必要性，以尽量减少抗生素耐药菌株的产生。
