Heydari Farzad Esavand, Bonyadian Mojtaba, Moshtaghi Hamdallah, Sami Masoud
Department of Health and Food Quality Control, Shahrekord University, Shahrekord, Iran.
Department of Health and Food Quality Control, Institute of Zoonoses Research, Shahrekord University, Shahrekord, Iran.
Iran J Microbiol. 2020 Aug;12(4):289-295. doi: 10.18502/ijm.v12i4.3931.
Enterohemorrhagic (EHEC) causes bloody and non-bloody diarrhea, intestinal infection and extraintestinal complications in humans. This study aimed to isolate and evaluate the prevalence of O157: H7 and other Shiga toxin-producing (STEC) and identify the virulence genes ( and ) from patients with diarrhea. Also, the antibiotic resistance profile of the isolated strains was evaluated.
A total of 100 stool samples were collected from patients with acute diarrhea referring to the hospital and clinics in Isfahan County, Iran. Phenotypic tests and PCR assay were used for detection of O157: H7 and other Shiga toxin-producing . The presence of virulence genes ( and ) were identified by PCR. The antibiotic resistance profile of the isolates was determined using the agar disk diffusion method. The results were analyzed descriptively by Sigma stat version 4 software.
Seventy - eight out of 100 samples (78%) were contaminated with O157 was isolated from five samples (6.4%), of which only two strains (2.56%) were identified as O157: H7. According to the results, out of two O157: H7 isolates, one (50%) isolate contained and two isolates (100%) contained genes. Out of three (3.84%) O157: HN, one of the isolate (33.3%) contained and, two isolates (66.7%) were positive for genes. Also, the results revealed that six strains (7.69%) were non-O157: H7 STEC, of which two isolates (33.3%) contained and four isolates (66.7%) were positive for and genes. The results of antibiogram tests revealed that all of the STEC isolates (100%) were sensitive to imipenem followed by kanamycin, gentamicin and nitrofurantoin (91%). High resistance (54.5%) to ampicillin and ciprofloxacin was observed among the STEC isolates.
The results of the current study showed that although the prevalence of O157: H7 was low among patients with diarrhea, the other STEC strains with relative resistance to antibiotics are more prevalent.
肠出血性大肠杆菌（EHEC）可导致人类出现血性和非血性腹泻、肠道感染及肠外并发症。本研究旨在从腹泻患者中分离并评估O157:H7及其他产志贺毒素大肠杆菌（STEC）的流行情况，鉴定其毒力基因（和），并评估分离菌株的抗生素耐药谱。
从伊朗伊斯法罕县医院和诊所的急性腹泻患者中总共收集了100份粪便样本。采用表型试验和PCR检测法检测O157:H7及其他产志贺毒素大肠杆菌。通过PCR鉴定毒力基因（和）的存在情况。采用琼脂纸片扩散法测定分离菌株的抗生素耐药谱。结果用Sigma stat 4软件进行描述性分析。
100份样本中有78份（78%）被污染，从5份样本（6.4%）中分离出O157，其中只有2株（2.56%）被鉴定为O157:H7。结果显示，在2株O157:H7分离株中，1株（50%）含有基因，2株（100%）含有基因。在3株（3.84%）O157:HN中，1株（33.3%）含有基因，2株（66.7%）的基因呈阳性。此外，结果显示有6株（7.69%）为非O157:H7 STEC，其中2株（33.3%）含有基因，4株（66.7%）的和基因呈阳性。药敏试验结果显示，所有STEC分离株（100%）对亚胺培南敏感，其次是卡那霉素、庆大霉素和呋喃妥因（91%）。STEC分离株对氨苄西林和环丙沙星的耐药性较高（54.5%）。
本研究结果表明，虽然腹泻患者中O157:H7的流行率较低，但其他对抗生素具有相对耐药性的STEC菌株更为普遍。
