Wild rats are known to carry different microorganisms and are considered a reservoir of zoonotic pathogens worldwide. The urban rats were collected from five districts of Tehran and Gram-negative bacteria (GNB) were isolated from fecal samples and were identified using classical biochemical tests. The antibiotic susceptibility patterns of isolated bacteria were determined by Kirby–Bauer disk diffusion method, the results of which were interpreted in line with CLSI guideline. The frequency of antibiotic-resistant genes was identified using multiplex-PCR. Moreover, PCR method was used to identify the frequency of Escherichia coli O157:H7 and main categories of diarrheagenic E. coli including EPEC, ETEC, EIEC, EAEC, and STEC pathotypes. A total of 100 Rattus norvegicus were trapped and fecal samples were collected. Overall, 72 fecal samples were positive for GNB. E. coli ( n = 46/72) had the highest frequency among the isolated GNB. Among E. coli isolates, the highest and lowest resistance rates belonged to ampicillin (56.5%) and ceftriaxone (0%), respectively. Klebsiella spp. was 100% resistant to imipenem, and streptomycin (0%) was the most effective antimicrobial agent on Klebsiella spp. Among surveyed genes, bla TEM (95.8%) and bla aadA-1 (58.3%) had the highest frequency, while bla KPC , and bla CMY-2 were not detected among Enterobacteriaceae . Herein, O157: H7 serotype was not detected and aEPEC (87%) was the most common pathotype detected. Results suggested that rodents might be a reservoir of antimicrobial-resistant pathogens and rodent control along with implementation of surveillance programs should be considered as a critical priority for urban health.

中文翻译：

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伊朗德黑兰共生褐家鼠携带的肠杆菌科成员的检测和表征

众所周知，野生大鼠携带不同的微生物，被认为是全世界人畜共患病原体的宿主。从德黑兰的五个地区收集城市大鼠，从粪便样本中分离出革兰氏阴性菌 (GNB)，并使用经典生化测试进行鉴定。分离细菌的抗生素敏感性模式通过柯比-鲍尔圆盘扩散法确定，其结果按照 CLSI 指南进行解释。使用多重PCR鉴定抗生素抗性基因的频率。此外，PCR方法用于鉴定大肠杆菌O157:H7的频率和主要的腹泻性大肠杆菌类别，包括EPEC、ETEC、EIEC、EAEC和STEC致病型。共捕获了 100 只褐家鼠并收集了粪便样本。全面的，72 份粪便样本呈 GNB 阳性。大肠杆菌 (n = 46/72) 在分离的 GNB 中频率最高。在大肠杆菌分离株中，最高和最低的耐药率分别属于氨苄青霉素 (56.5%) 和头孢曲松 (0%)。克雷伯氏菌属 对亚胺培南 100% 耐药，链霉素 (0%) 是对克雷伯氏菌最有效的抗菌剂。在调查的基因中，bla TEM (95.8%) 和bla aadA-1 (58.3%) 的频率最高，而bla KPC 和bla CMY-2 在肠杆菌科中未检测到。在此，O157：H7 血清型未检测到，aEPEC (87%) 是最常见的致病型。结果表明，啮齿动物可能是抗微生物病原体的宿主，啮齿动物控制以及监测计划的实施应被视为城市健康的关键优先事项。