Epidemiology, Surveilance and Risk Group, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, Surrey KT15 3NB, UK.
Vet Microbiol. 2012 Nov 9;160(1-2):197-206. doi: 10.1016/j.vetmic.2012.05.029. Epub 2012 May 30.
Escherichia coli, the most common cause of bacteraemia in humans in the UK, can also cause serious diseases in animals. However the population structure, virulence and antimicrobial resistance genes of those from extraintestinal organs of livestock animals are poorly characterised. The aims of this study were to investigate the diversity of these isolates from livestock animals and to understand if there was any correlation between the virulence and antimicrobial resistance genes and the genetic backbone of the bacteria and if these isolates were similar to those isolated from humans. Here 39 E. coli isolates from liver (n=31), spleen (n=5) and blood (n=3) of cattle (n=34), sheep (n=3), chicken (n=1) and pig (n=1) were assigned to 19 serogroups with O8 being the most common (n=7), followed by O101, O20 (both n=3) and O153 (n=2). They belong to 29 multi-locus sequence types, 20 clonal complexes with ST23 (n=7), ST10 (n=6), ST117 and ST155 (both n=3) being most common and were distributed among phylogenetic group A (n=16), B1 (n=12), B2 (n=2) and D (n=9). The pattern of a subset of putative virulence genes was different in almost all isolates. No correlation between serogroups, animal hosts, MLST types, virulence and antimicrobial resistance genes was identified. The distributions of clonal complexes and virulence genes were similar to other extraintestinal or commensal E. coli from humans and other animals, suggesting a zoonotic potential. The diverse and various combinations of virulence genes implied that the infections were caused by different mechanisms and infection control will be challenging.
大肠埃希菌是英国人类血液感染中最常见的病原体，也可导致动物发生严重疾病。然而，家畜肠道外器官来源的大肠埃希菌的种群结构、毒力和抗菌药物耐药基因的特征尚不清楚。本研究的目的是调查这些家畜来源分离株的多样性，了解其毒力和抗菌药物耐药基因与细菌遗传背景之间是否存在相关性，以及这些分离株是否与人类分离株相似。本研究从牛（n=34）、羊（n=3）、鸡（n=1）和猪（n=1）的肝脏（n=31）、脾脏（n=5）和血液（n=3）中分离得到 39 株大肠埃希菌，血清型鉴定到 19 个血清群，其中 O8 血清型最为常见（n=7），其次是 O101、O20（均 n=3）和 O153（n=2）。这些菌株分属于 29 个多位点序列型，20 个克隆群，其中 ST23（n=7）、ST10（n=6）、ST117 和 ST155（均 n=3）最为常见，这些菌株分布在 A 群（n=16）、B1 群（n=12）、B2 群（n=2）和 D 群（n=9）中。几乎所有分离株的一组假定毒力基因的模式都不同。血清型、动物宿主、MLST 型、毒力和抗菌药物耐药基因之间没有相关性。克隆群和毒力基因的分布与其他肠道外或共生大肠埃希菌从人类和其他动物中分离到的相似，提示存在人畜共患病的可能性。不同的毒力基因组合暗示感染可能由不同的机制引起，感染控制将具有挑战性。
