Department of Pathology and Parasitology, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram, Bangladesh.
Melbourne Veterinary School, Faculty of Science, University of Melbourne, Parkville, Australia.
Vet Med Sci. 2024 Nov;10(6):e70032. doi: 10.1002/vms3.70032.
The emergence and dissemination of multidrug resistant (MDR) bacteria pose a severe threat to public health by limiting clinical treatment and prophylactic options.
This study investigates the prevalence of Escherichia coli in broilers, their phenotypic antimicrobial resistance (AMR) profiles and the presence of virulence-associated genes (VAGs) and antimicrobial resistance genes (ARGs) using polymerase chain reaction (PCR).
A total of 216 pooled cloacal samples were collected from 1080 broilers across six districts of Bangladesh. Each pooled sample comprised randomly selected cloacal swabs from five birds per farm. E. coli isolates were identified using standard bacteriological approach, followed by biochemical assays and PCR. Antimicrobial susceptibility was assessed using the Kirby-Bauer disc diffusion method, and the presence of ARGs and VAGs was determined via PCR. Five selected isolates were partially sequenced for five VAGs using Sanger sequencing.
A total of 177 E. coli isolates (81.94%, 95% confidence interval: 76.24%-86.53%) were identified. The isolates showed the highest resistance to ampicillin (93.79%), followed by tetracycline (91.53%), erythromycin (89.27%) and ciprofloxacin (87%). Conversely, ceftriaxone (80.79%) showed highest susceptibility, followed by gentamicin (37.29%) and neomycin (31.07%). All isolates were MDR, with a multiple antibiotic resistance indexes were <0.3. A significant percentage (16.38%) of E. coli isolates were MDR to five antimicrobial classes and harboured bla, sul1, ere (A), tetA, tetB and tetC genes. The highest prevalent ARGs were bla (88.14%) followed by ere (A) (83.62%) and sul 1 (72.32%). The prevalence of VAGs was astA (56.50%), iucD (31.07%), iss (21.47%), irp2 (15.82%) and cva/cvi (3.39%), respectively.
This study highlights the presence of ARGs contributing to the development of MDR in E. coli carrying VAGs in broilers. Effective monitoring and surveillance of antimicrobial usage in poultry production systems are urgently required to prevent emergence and dissemination of AMR.
多药耐药（MDR）细菌的出现和传播对公共卫生构成了严重威胁，限制了临床治疗和预防选择。
本研究使用聚合酶链反应（PCR）调查孟加拉国六个地区肉鸡中大肠杆菌的流行情况、其表型抗菌药物耐药（AMR）谱以及毒力相关基因（VAGs）和抗菌药物耐药基因（ARGs）的存在情况。
从孟加拉国六个地区的 1080 只肉鸡中采集了 216 个组合的泄殖腔样本。每个组合样本由每个农场的五只鸡随机选择的泄殖腔拭子组成。使用标准细菌学方法鉴定大肠杆菌分离株，然后进行生化检测和 PCR。使用 Kirby-Bauer 圆盘扩散法评估抗菌药物敏感性，通过 PCR 确定 ARGs 和 VAGs 的存在。使用 Sanger 测序对 5 个选定的分离株的 5 个 VAGs 进行部分测序。
共鉴定出 177 株大肠杆菌分离株（81.94%，95%置信区间：76.24%-86.53%）。这些分离株对氨苄西林（93.79%）的耐药性最高，其次是四环素（91.53%）、红霉素（89.27%）和环丙沙星（87%）。相反，头孢曲松（80.79%）的敏感性最高，其次是庆大霉素（37.29%）和新霉素（31.07%）。所有分离株均为多重耐药，其多重抗生素耐药指数均<0.3。大肠杆菌分离株中有 16.38%对 5 种抗菌药物类别的耐药性较高，且携带 bla、sul1、ere（A）、tetA、tetB 和 tetC 基因。最常见的 ARGs 是 bla（88.14%），其次是 ere（A）（83.62%）和 sul1（72.32%）。VAGs 的流行率分别为 astA（56.50%）、iucD（31.07%）、iss（21.47%）、irp2（15.82%）和 cva/cvi（3.39%）。
本研究强调了在携带 VAGs 的肉鸡中，携带 ARGs 的大肠杆菌对 MDR 的发展。迫切需要对家禽生产系统中抗菌药物的使用进行有效监测和监测，以防止 AMR 的出现和传播。
