Sváb Domonkos, Falgenhauer Linda, Mag Tünde, Chakraborty Trinad, Tóth István
Veterinary Medical Research Institute, Budapest, Hungary.
Institute of Hygiene and Environmental Medicine and German Center for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Justus Liebig University Giessen, Giessen, Germany.
Front Microbiol. 2022 Jul 5;13:896296. doi: 10.3389/fmicb.2022.896296. eCollection 2022.
belonging to the enterohemorrhagic (EHEC), Shiga toxin-producing (STEC) and atypical enteropathogenic (aEPEC) pathotypes are significant foodborne zoonotic pathogens posing serious health risks, with healthy cattle as their main reservoir. A representative sampling of Hungarian cattle farms during 2017-2018 yielded a prevalence of 6.5 and 5.8% for STEC and aEPEC out of 309 samples. The draft genomes of twelve STEC (of them 9 EHEC) and four aEPEC of bovine origin were determined. For comparative purposes, we also included 3 EHEC and 2 aEPEC strains of human origin, as well four commensal isolates and one extraintestinal pathogenic (ExPEC) obtained from animals in a final set of 26 strains for a WGS-based analysis. Apart from key virulence genes, these isolates harbored several additional virulence genes with arrays characteristic for the site of isolation. The most frequent insertion site of Shiga toxin encoding prophages was for the Stx1 prophage and and for Stx2. For O157:H7 strains, the locus of enterocyte effacement pathogenicity island was present at the site, with integration at for other serotypes, and in the case of O26:H11 strains. Several LEE-negative STEC and aEPEC as well as commensal isolates carried additional prophages, with an average of ten prophage regions per isolate. Comparative phylogenomic analysis showed no clear separation between bovine and human lineages among the isolates characterized in the current study. Similarities in virulence gene arrays and close phylogenetic relations of bovine and human isolates underline the zoonotic potential of bovine aEPEC and STEC and emphasize the need for frequent monitoring of these pathogens in livestock.
肠出血性大肠杆菌（EHEC）、产志贺毒素大肠杆菌（STEC）和非典型肠致病性大肠杆菌（aEPEC）属于重要的食源性人畜共患病原体，会带来严重的健康风险，健康牛是其主要宿主。2017 - 2018年对匈牙利养牛场进行的代表性抽样显示，在309份样本中，STEC和aEPEC的检出率分别为6.5%和5.8%。测定了12株牛源STEC（其中9株为EHEC）和4株牛源aEPEC的基因组草图。为了进行比较，我们还纳入了3株人源EHEC和2株人源aEPEC菌株，以及从动物中获得的4株共生菌和1株肠道外致病性（ExPEC）菌株，最终共有26株菌株用于基于全基因组测序（WGS）的分析。除关键毒力基因外，这些分离株还含有一些额外的毒力基因，其排列具有分离部位的特征。编码志贺毒素的前噬菌体最常见的插入位点是Stx1前噬菌体的[具体位点1]和Stx2的[具体位点2]。对于O157:H7菌株，肠细胞脱落致病性岛位于[具体位点3]，其他血清型在[具体位点4]整合，O26:H11菌株则在[具体位点5]。几株LEE阴性的STEC和aEPEC以及共生菌分离株携带额外的前噬菌体，每个分离株平均有10个前噬菌体区域。比较系统发育基因组分析表明，在本研究中鉴定的分离株中，牛源和人源谱系之间没有明显的区分。牛源和人源分离株在毒力基因阵列上的相似性以及密切的系统发育关系，突显了牛源aEPEC和STEC的人畜共患病潜力，并强调了对家畜中这些病原体进行频繁监测的必要性。
