Faculty of Veterinary Medicine, Ferdowsi University of Mashhad.
Department of Pathobiology, Faculty of Veterinary Medicine, Islamic Azad University- Garmsar branch, Garmsar, Iran
Vet Ital. 2021 Dec 31;57(3). doi: 10.12834/VetIt.2269.13773.1.
The poultry industry in Iran is the main supplier of protein in the food chain. In the present study, we showed the importance of the possible dissemination of clonally related multiple drug resistant (MDR) Salmonella Infantis in broiler farms in Iran. In total, 156 fecal samples belonging to 23 poultry farms in Razavi Khorasan province, northeast of Iran, were examined for the presence of Salmonella serovars. Molecular serotypes and serogroups, class 1 and 2 integron types, colistin resistance genes ( mcr1 and mcr2) and antimicrobial susceptibility patterns were determined on the recovered Salmonella isolates. Based on PCR analysis, 30 recovered Salmonella isolates were identified asS. Infantis (23 isolates; 76.6%),S. Enteritidis (six isolates; 20%), and one isolate (3.3%) was not serotyped by the applied method. Class 1 integrons were detected in 22 isolates (95.6%) and class 2 integrons were not detected in any of the isolates. Although colistin resistance was prevalent in disc diffusion test, mcr-1 and mcr-2 genes were not detected. All class 1 integrons carried the cassette aadA1 gene. All Salmonella isolates were resistant to colistin and amoxicillin/clavulanic acid and MDR patterns were observed in most (96.6%) isolates. This study revealed a high prevalence rate of S. Infantis and the presence of class 1 integrons in broiler farms. The presence of the same integron cassettes in the sequenced isolates suggests that strains are clonally related. Stringent monitoring programs are required to prevent the spreading of MDR Salmonella serovars into food chain via poultry products.
伊朗的家禽业是食物链中蛋白质的主要供应者。在本研究中，我们表明了在伊朗肉鸡养殖场中，克隆相关的多重耐药（MDR）肠炎沙门氏菌可能传播的重要性。总共检查了来自伊朗东北部拉扎维霍拉桑省 23 个家禽养殖场的 156 份粪便样本，以确定沙门氏菌血清型的存在。在回收的沙门氏菌分离物上确定了分子血清型和血清群、1 类和 2 类整合子类型、黏菌素耐药基因（mcr1 和 mcr2）和抗菌药物敏感性模式。基于 PCR 分析，从 30 株回收的沙门氏菌分离物中鉴定出 23 株（76.6%）为肠炎沙门氏菌、6 株（20%）为肠炎沙门氏菌和 1 株（3.3%）未通过应用方法定型。在 22 株分离物中检测到 1 类整合子（95.6%），未在任何分离物中检测到 2 类整合子。虽然在圆盘扩散试验中普遍存在黏菌素耐药性，但未检测到 mcr-1 和 mcr-2 基因。所有 1 类整合子都携带 aadA1 基因盒。所有沙门氏菌分离物均对黏菌素和阿莫西林/克拉维酸耐药，且大多数（96.6%）分离物表现出 MDR 模式。本研究揭示了肉鸡养殖场中肠炎沙门氏菌和 1 类整合子的高流行率。测序分离物中存在相同的整合子盒表明菌株具有克隆相关性。需要实施严格的监测计划，以防止 MDR 沙门氏菌血清型通过禽产品传播到食物链中。
