Servicio Fisiopatogenia, Departamento de Bacteriología, Instituto Nacional de Enfermedades Infecciosas-ANLIS Dr. Carlos G. Malbrán, Av. Vélez Sarsfield 563, 1281 Buenos Aires, Argentina.
Vet Microbiol. 2010 Jul 14;143(2-4):307-13. doi: 10.1016/j.vetmic.2009.11.028. Epub 2009 Nov 27.
For comparison purposes, the prevalence of 8 virulence markers was investigated, by PCR, in 153 cattle and 47 human Locus for Enterocyte Effacement (LEE)-negative Shiga toxin-producing Escherichia coli (STEC) strains isolated in Argentina. Also, their correlation with severe disease was established. The virulence markers studied comprises 5 fimbrial and nonfimbrial adhesin-encoding genes (fimA, iha, efa1, lpfA(O113), and saa) and 3 toxin genes (cdt-V, subAB and astA) in addition to the Shiga toxins. The most prevalent virulence marker found was that encoded by the lpfA(O113) gene (199/200, 99%). Comparatively, the lpfA(O113), fimA, iha, saa, subAB, cdt-V and astA genes were detected in 100%, 92.8%, 85%, 52.9%, 36%, 11.8% and 9.8% of the cattle strains and in 97.9%, 95.7%, 89.4%, 40.4%, 32%, 17% and 10.6% of the human strains, respectively. All STEC strains were efa1 negative. The most prevalent profile observed among cattle and human STEC strains was lpfA(O113)iha fimA. These results show that bovine LEE-negative STEC strains possessed genes encoding virulence factors present in human LEE-negative STEC strains that are associated with disease. Despite a great diversity of virulence profiles observed, further studies comparing wild type strains and their allelic mutants are needed to evaluate the role of each factor in the pathogenesis of LEE-negative STEC strains during human infections.
为了进行比较，通过 PCR 检测了在阿根廷分离的 153 株牛源和 47 株人源 LEE 阴性志贺毒素产生大肠杆菌（STEC）菌株中的 8 种毒力标记物的流行情况，并确定了它们与严重疾病的相关性。研究的毒力标记物包括 5 种菌毛和非菌毛粘附素编码基因（fimA、iha、efa1、lpfA(O113)和 saa）和 3 种毒素基因（cdt-V、subAB 和 astA）以及志贺毒素。发现最常见的毒力标记物是由 lpfA(O113)基因编码的（199/200，99%）。相对而言，lpfA(O113)、fimA、iha、saa、subAB、cdt-V 和 astA 基因分别在 100%、92.8%、85%、52.9%、36%、11.8%和 9.8%的牛源菌株和 97.9%、95.7%、89.4%、40.4%、32%、17%和 10.6%的人源菌株中被检测到。所有 STEC 菌株均为 efa1 阴性。在牛源和人源 STEC 菌株中观察到的最常见的毒力谱是 lpfA(O113)iha fimA。这些结果表明，牛源 LEE 阴性 STEC 菌株具有编码与疾病相关的人源 LEE 阴性 STEC 菌株中存在的毒力因子的基因。尽管观察到了多样性的毒力谱，但需要进一步比较野生型菌株及其等位基因突变体的研究，以评估每个因子在人感染 LEE 阴性 STEC 菌株发病机制中的作用。
