Han Yue, Liu Minqi, Han Ying, Shi Naiyang, Wang Qiang, Cui Tingting, Yang Liuqing, Zhang Xuefeng, Zhu Liguo, Qian Huimin, Jin Hui, Dong Chen
Key Laboratory of Environmental Medicine Engineering, Ministry of Education School of Public Health Southeast University, Nanjing, China.
Department of Epidemiology and Health Statistics School of Public Health, Southeast University, Nanjing, China.
J Appl Microbiol. 2022 May;132(5):3925-3936. doi: 10.1111/jam.15494. Epub 2022 Feb 26.
There are knowledge gaps regarding STEC and EPEC strains in livestock in Jiangsu, China. This study aimed to evaluate the potential public health significance of STEC and EPEC strains isolated from livestock by determining the serotypes, virulence profiles, and genetic relationship with international STEC strains.
A total of 68 STEC and 37 EPEC strains were obtained from 231 faecal sheep samples and 70 faecal cattle samples. By using whole-genome sequencing (WGS) analysis, all STEC belonged to 15 O: H serotypes, and the most prevalent serotypes were O6:H10 (19.1%), O155:H21 (14.7%), and O21:H25 (10.3%). The main Shiga toxin gene subtypes detected were stx1c (41.2%), stx1a (26.5%), stx2b (14.7%), and stx2k (14.7%). Only the STEC from cattle carried eae gene. Other adherence-associated or toxin-related genes, including lpfA (70.6%), iha (48.5%), subA (54.4%), and ehxA (33.8%), were found in STEC. All EPEC strains were bfpA-negative, and the predominant eae variants were eae-β1 (62.2%), eae-ζ (21.6%), and eae-θ (8.1%). The core-genome multi-locus sequence typing (cgMLST) analysis revealed nine scattered clusters in STEC and one dominant cluster in EPEC. The strains with the same serotypes, including O22:H8 and O43:H2 in the two towns, possessed a closely genomic distance. The core genome single-nucleotide polymorphism (cgSNP) showed that part of STEC strains in this study was clustered with isolates possessing the same serotypes from the Netherlands, Sweden, and Xinjiang of China. Five serotypes of STEC isolates were associated with the clinical STEC strains from databases.
This study provided the diverse serotypes and the virulence genes profiles in STEC and EPEC strains. Local strains possessed widely diverse and scattered clusters by cgMLST. Closely genomic correlation with clinical isolates displayed that part of the STEC strains may threaten to public health.
Non-O157 STEC strains act as important pathogens for human infections. This study supports the increased surveillance work of non-O157 STEC rather than just O157 STEC in this region.
在中国江苏省，关于家畜中的肠出血性大肠杆菌（STEC）和肠致病性大肠杆菌（EPEC）菌株存在知识空白。本研究旨在通过确定血清型、毒力谱以及与国际STEC菌株的遗传关系，评估从家畜中分离出的STEC和EPEC菌株对公共卫生的潜在重要性。
从231份绵羊粪便样本和70份牛粪便样本中总共获得了68株STEC和37株EPEC菌株。通过全基因组测序（WGS）分析，所有STEC属于15种O:H血清型，最常见的血清型为O6:H10（19.1%）、O155:H21（14.7%）和O21:H25（10.3%）。检测到的主要志贺毒素基因亚型为stx1c（41.2%）、stx1a（26.5%）、stx2b（14.7%）和stx2k（14.7%）。仅牛源的STEC携带eae基因。在STEC中还发现了其他与黏附相关或毒素相关的基因，包括lpfA（70.6%）、iha（48.5%）、subA（54.4%）和ehxA（33.8%）。所有EPEC菌株均为bfpA阴性，主要的eae变体为eae-β1（62.2%）、eae-ζ（21.6%）和eae-θ（8.1%）。核心基因组多位点序列分型（cgMLST）分析显示STEC中有9个分散的簇，EPEC中有1个主要簇。两个镇中具有相同血清型的菌株，如O22:H8和O43:H2，基因组距离较近。核心基因组单核苷酸多态性（cgSNP）表明，本研究中的部分STEC菌株与来自荷兰、瑞典和中国新疆的具有相同血清型的分离株聚类在一起。5种血清型的STEC分离株与数据库中的临床STEC菌株相关。
本研究提供了STEC和EPEC菌株多样的血清型和毒力基因谱。通过cgMLST分析，本地菌株具有广泛多样且分散的簇。与临床分离株密切的基因组相关性表明部分STEC菌株可能对公共卫生构成威胁。
非O157 STEC菌株是人类感染的重要病原体。本研究支持在该地区加强对非O157 STEC而非仅O157 STEC的监测工作。
