Hornitzky M A, Bettelheim K A, Djordjevic S P
Elizabeth Macarthur Agricultural Institute, New South Wales Agriculture, National Escherichia coli Reference, Private Mail Bag, 8, Camden, NSW 2570 Australia.
FEMS Microbiol Lett. 2001 Apr 20;198(1):17-22. doi: 10.1111/j.1574-6968.2001.tb10613.x.
The prevalence of complex Shiga toxin-producing Escherichia coli (STEC), i.e. STEC containing accessory virulence factors intimin (eaeA) and/or enterohaemorrhagic E. coli haemolysin (ehxA) and their serotypes were determined in diagnostic bovine faecal samples processed during a 3 months period. The presence of complex STEC was determined using PCR and vancomycin-cefixime-cefsulodin blood agar (BVCCA) using a dual approach which involved (i) direct culture of faecal samples on BVCCA followed by mutiplex PCR of BVCCA positive colonies and (ii) culture of faecal samples enriched in modified EC (mEC) broth (with a complex STEC profile determined by PCR) on BVCCA followed by multiplex PCR of BVCCA positive colonies. Using both techniques complex STEC were isolated from 23 (18.7%) of the 123 faecal samples. Complex STEC were isolated from 14 faecal samples by direct culture on BVCCA and 13 faecal samples yielded complex STEC by culture of mEC broths with a complex STEC profile on BVCCA. Only four samples were positive using both techniques. The serotypes isolated included O5:H-, O26:H-, O26:H11, O91:H21, O111:H-, O111:H8, O104:H11, O113:H21 and O157:H8. This study confirms that non-O157 STEC can be isolated from bovine faeces and that they carry types associated with human disease. This work also demonstrates that the use of a dual approach is advisable to increase the likelihood of isolating complex STEC.
在三个月期间对用于诊断的牛粪便样本进行检测，以确定产志贺毒素大肠杆菌（STEC）复合体的流行情况，即含有辅助毒力因子紧密黏附素（eaeA）和/或肠出血性大肠杆菌溶血素（ehxA）的STEC及其血清型。采用双重方法，通过PCR和万古霉素 - 头孢克肟 - 头孢磺啶血琼脂（BVCCA）检测复杂STEC的存在，该方法包括：（i）将粪便样本直接接种于BVCCA上进行培养，随后对BVCCA阳性菌落进行多重PCR；（ii）将在改良EC（mEC）肉汤中富集的粪便样本（通过PCR确定具有复杂STEC谱）接种于BVCCA上进行培养，随后对BVCCA阳性菌落进行多重PCR。使用这两种技术，从123份粪便样本中的23份（18.7%）中分离出了复杂STEC。通过直接接种于BVCCA从14份粪便样本中分离出复杂STEC，通过将具有复杂STEC谱的mEC肉汤接种于BVCCA从13份粪便样本中分离出复杂STEC。只有4份样本在两种技术下均呈阳性。分离出的血清型包括O5:H - 、O26:H - 、O26:H11、O91:H21、O111:H - 、O111:H8、O104:H11、O113:H21和O157:H8。本研究证实，非O157 STEC可从牛粪便中分离出来，并且它们携带与人类疾病相关的类型。这项工作还表明，采用双重方法有助于提高分离复杂STEC的可能性。
