Departamento de Patologia Veterinária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, SP, Brazil.
OIE Reference Laboratory for Escherichia coli (EcL), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada.
Vet Microbiol. 2014 Feb 21;169(1-2):89-95. doi: 10.1016/j.vetmic.2013.12.013. Epub 2013 Dec 25.
Sheep harbor pathogenic Escherichia coli, which may cause severe disease in humans. In this study, the prevalence of Shiga toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC) was examined in sheep feces and carcasses on three farms and at an abattoir in Brazil. The isolates were further characterized for the presence of markers recently associated with disease in humans, to investigate their possible origin and role as food-borne pathogens. At the abattoir, 99 carcass samples yielded two STEC and 10 EPEC isolates while 101 fecal samples yielded five EPEC and eight STEC isolates. On the other hand, on the farms, 202 samples yielded 44 STEC and eight EPEC isolates. The 77 isolates were typed by PFGE. Isolates with the same PFGE pattern and also those that were not restricted with XbaI were termed as "clones" (n=49). The isolates of any one clone mostly originated from the same sampling site. In addition, seven isolates encoded for novel Stx2 variants and five for Stx2e, the subtype related to porcine edema disease, which was for the first time isolated from sheep feces and carcasses. Also, three stx2-only isolates harbored genes of predicted Stx2 variants that were formed by A and B subunits of different types including Stx2a and Stx2d. The EPEC isolates were heterogeneous, 21 (91.3%) of them possessing efa1, ehxA, lpfAO113 or paa genes associated with diarrhea in humans. Thus, using markers recently associated with disease, we have demonstrated that E. coli similar to those pathogenic for humans are present in the sheep intestinal microflora, particularly at the abattoir, underlining the potential for food-borne transmission.
绵羊携带致病性大肠杆菌，可能导致人类严重疾病。本研究在巴西的三个农场和一个屠宰场检测了绵羊粪便和胴体中的产志贺毒素大肠杆菌（STEC）和肠致病性大肠杆菌（EPEC）的流行情况。进一步对分离株进行了特征分析，以确定其与人类疾病相关的标记物，以研究其可能的来源和作为食源性致病菌的作用。在屠宰场，99 个胴体样本中分离出 2 株 STEC 和 10 株 EPEC 分离株，而 101 个粪便样本中分离出 5 株 EPEC 和 8 株 STEC 分离株。另一方面，在农场，202 个样本中分离出 44 株 STEC 和 8 株 EPEC 分离株。77 个分离株通过 PFGE 进行了分型。具有相同 PFGE 模式的分离株和未被 XbaI 限制的分离株被称为“克隆”（n=49）。任何一个克隆的分离株主要来自同一个采样点。此外，有 7 个分离株编码新型 Stx2 变体，5 个分离株编码 Stx2e，该亚型与猪水肿病有关，这是首次从绵羊粪便和胴体中分离出来。此外，有 3 个仅携带 stx2 的分离株携带不同类型的 A 和 B 亚单位组成的预测 Stx2 变体的基因，包括 Stx2a 和 Stx2d。EPEC 分离株具有异质性，其中 21 株（91.3%）携带与人腹泻相关的 efa1、ehxA、lpfAO113 或 paa 基因。因此，使用与疾病相关的标记物，我们证明了类似于人类致病的大肠杆菌存在于绵羊肠道微生物群中，特别是在屠宰场，强调了食源性传播的潜力。
