SHIGATOXIN-PRODUCING ESCHERICHIA COLI DETECTED IN DAIRY CATTLE FECES

ABSTRACT The purpose of this study was to determine the prevalence of Shigatoxigenic Escherichia coli (STEC) and serogroups O157, O111 and O113 in dairy cattle from Jaboticabal, state of São Paulo, Brazil. Feces samples were collected from 10 herds and assessed for the presence of the virulence genes stx1, stx2 and eae by polymerase chain reaction (PCR). All samples positive for stx and eae were submitted to a second PCR reaction targeting the sequences rfb O157, rfb O111 and rfb O113. A high prevalence of stx (72.16%) was detected in the fecal samples, the most frequent being stx1 associated to stx2. The prevalence of sequences rfb O157, rfb O111 and rfb O113 was 14.77%, 0.2% and 30.83%, respectively. STEC and serogroup O113 was identified in all herds (100%), and serogroups O157 and O111 were observed in 60% and 10% of the herds. In conclusion, the high STEC prevalence detected in dairy herds evidences that bovine feces might play an important role as a contamination source in the region of Jaboticabal.

摘要 本研究旨在明确巴西圣保罗州雅博蒂卡瓦尔地区乳牛中产志贺毒素大肠杆菌（Shigatoxigenic Escherichia coli, STEC）以及O157、O111、O113血清群的流行率。研究人员从10个牛群中采集粪便样本，通过聚合酶链反应（Polymerase Chain Reaction, PCR）检测样本中毒力基因stx1、stx2与eae的存在情况。所有stx与eae检测呈阳性的样本，将接受第二轮靶向扩增rfb O157、rfb O111及rfb O113序列的PCR反应。粪便样本中stx的检出率高达72.16%，其中最常见的为stx1与stx2联合阳性。rfb O157、rfb O111及rfb O113序列的检出率分别为14.77%、0.2%与30.83%。所有10个牛群中均检出STEC与O113血清群（100%），60%的牛群检出O157血清群，10%的牛群检出O111血清群。综上，本次研究在乳牛牛群中检出的高STEC流行率表明，牛粪便可能是雅博蒂卡瓦尔地区污染的重要传染源之一。