Ghanbarpour Reza, Kiani Mojtaba
Microbiology Department of Faculty of Veterinary Medicine, Shahid Bahonar University, 76169-14111, Kerman, Iran.
Trop Anim Health Prod. 2013 Feb;45(2):641-8. doi: 10.1007/s11250-012-0271-5. Epub 2012 Sep 27.
The objectives of this study were to determine the presence and prevalence of non-O157 shiga toxin-producing Escherichia coli (STEC) isolates from faeces of healthy fat-tailed sheep and detection of phylogenetic background and antibiotic resistance profile of isolates. One hundred ninety-two E. coli isolates were recovered from obtained rectal swabs and were confirmed by biochemical tests. Antibiotic resistance profiles of isolates were detected and phylogenetic background of isolates was determined according to the presence of the chuA, yjaA and TspE4.C2 genetic markers. The isolates were examined to determine stx (1), stx (2) and eae genes. Non-O157 STEC isolates were identified by using O157 specific antiserum. Forty-three isolates (22.40 %) were positive for one of the stx (1), stx (2) and eae genes, whereas 10.42 % were positive for stx (1), 19.38 % for eae and 2.60 % for stx (2) gene. None of the positive isolates belonged to O157 serogroup. Twenty isolates possessed stx ( 1 ) were distributed in A (six isolates), B1 (13) and D (one) phylogroups, whereas stx (2) positive isolates fell into A (three isolates) and B1 (two) phylogenetic groups. Eighteen isolates contained eae gene belonged to A (five isolates), B1 (seven) and D (six) phylogroups. The maximum and minimum resistance rates were recorded against to penicillin and co-trimoxazole respectively. The positive isolates for stx (1), stx (2) and eae genes showed several antibiotic resistance patterns, whereas belonged to A, B1 and D phylogroups. In conclusion, faeces of healthy sheep could be considered as the important sources of non-O157 STEC and also multidrug-resistant E. coli isolates.
本研究的目的是确定健康肥尾羊粪便中产生志贺毒素的非O157大肠杆菌（STEC）分离株的存在情况和流行率，并检测分离株的系统发育背景和抗生素耐药谱。从采集的直肠拭子中分离出192株大肠杆菌分离株，并通过生化试验进行确认。检测分离株的抗生素耐药谱，并根据chuA、yjaA和TspE4.C2基因标记的存在情况确定分离株的系统发育背景。对分离株进行检测以确定stx（1）、stx（2）和eae基因。使用O157特异性抗血清鉴定非O157 STEC分离株。43株分离株（22.40%）stx（1）、stx（2）和eae基因之一呈阳性，而stx（1）基因阳性率为10.42%，eae基因阳性率为19.38%，stx（2）基因阳性率为2.60%。阳性分离株均不属于O157血清型。20株携带stx（1）的分离株分布在A（6株）、B1（13株）和D（1株）系统发育群中，而stx（2）阳性分离株属于A（3株）和B1（2株）系统发育群。18株含有eae基因的分离株属于A（5株）、B1（7株）和D（6株）系统发育群。对青霉素和复方新诺明的耐药率分别为最高和最低。stx（1）、stx（2）和eae基因阳性的分离株表现出多种抗生素耐药模式，且属于A、B1和D系统发育群。总之，健康绵羊的粪便可被视为非O157 STEC以及多重耐药大肠杆菌分离株的重要来源。
