Phylogenomic approaches to determine the zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) isolated from Zambian dairy cattle.
Phylogenomic approaches to determine the zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) isolated from Zambian dairy cattle.
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DOI：
10.1038/srep26589
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发表时间：
2016-05-25
影响因子：
4.6
通讯作者：
Gally DL
中科院分区：
文献类型：
--
作者：
Mainda G;Lupolova N;Sikakwa L;Bessell PR;Muma JB;Hoyle DV;McAteer SP;Gibbs K;Williams NJ;Sheppard SK;La Ragione RM;Cordoni G;Argyle SA;Wagner S;Chase-Topping ME;Dallman TJ;Stevens MP;Bronsvoort BM;Gally DL
本研究评估了从赞比亚中部地区104个奶牛场采样的产滋贺毒素大肠杆菌（STEC）的流行率和人畜共患病潜力，并将其与同一地区腹泻患者的分离株进行了比较。297 E.对大肠杆菌菌株进行测序，允许对phylo和sero-groups进行计算机分析。大多数牛菌株聚集在B1 'Escherosal' Escherosal群（67%）中，并包括多种血清群。11%（41/371）的赞比亚奶牛分离株含有滋贺毒素基因（stx），而73株人源分离株均为阴性。虽然证明了这些分离株的一个子集的毒性，但随机选择的STEC均不属于与人类疾病相关的关键血清群，也不编码与典型肠出血菌株同义的3型分泌系统。对E.大肠杆菌O 157：H7在整个养殖场中仅鉴定出一个阳性分离株，再次表明该血清型在这些动物中很罕见。综上所述，Stx编码的E.大肠杆菌菌株在这个乳制品群体中很常见，但这些菌株中的大多数不太可能在人类中引起疾病。然而，从这个水库中出现对人类有毒的菌株的威胁仍然存在。
This study assessed the prevalence and zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) sampled from 104 dairy units in the central region of Zambia and compared these with isolates from patients presenting with diarrhoea in the same region. A subset of 297 E. coli strains were sequenced allowing in silico analyses of phylo- and sero-groups. The majority of the bovine strains clustered in the B1 ‘commensal’ phylogroup (67%) and included a diverse array of serogroups. 11% (41/371) of the isolates from Zambian dairy cattle contained Shiga toxin genes (stx) while none (0/73) of the human isolates were positive. While the toxicity of a subset of these isolates was demonstrated, none of the randomly selected STEC belonged to key serogroups associated with human disease and none encoded a type 3 secretion system synonymous with typical enterohaemorrhagic strains. Positive selection for E. coli O157:H7 across the farms identified only one positive isolate again indicating this serotype is rare in these animals. In summary, while Stx-encoding E. coli strains are common in this dairy population, the majority of these strains are unlikely to cause disease in humans. However, the threat remains of the emergence of strains virulent to humans from this reservoir.