从巴西牛肉中分离的大肠杆菌的基因组特征和耐热性特征。

Genomic features and heat resistance profiles of Escherichia coli isolated from Brazilian beef.

机构信息

Postgraduate Program in Food, Nutrition and Metabolism (PPGNAM), Federal University of Mato Grosso (UFMT), Cuiabá, Mato Grosso 78060-900, Brazil.

Postgraduate program in Food Science (PPGCAL), Chemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro 21941-909, Brazil.

出版信息

J Appl Microbiol. 2023 Jan 23;134(1). doi: 10.1093/jambio/lxac027.

DOI:10.1093/jambio/lxac027

PMID:36724247

Abstract

AIMS

Characterize Escherichia coli and E. coli -producing (STEC) isolates from Brazilian beef to determine heat resistance and the presence of the transmissible locus of stress tolerance (tLST).

METHODS AND RESULTS

Twenty-two STEC previously isolated from beef and characterized as STEC by PCR were subjected to different heat survival challenges (60°C and 71°C). Furthermore, the three tLST-positive isolates and one tLST-negative isolate by PCR were selected for WGS analysis. Phenotypic results indicated that 3/22 (13.64%) were heat resistant, 12/22 (54.54%) were moderately resistant, and 7/22 (31.82%) were sensitive to heat treatments. WGS analyses showed that three isolates with heat resistance showed tLST with up to 80% and 42% of similarity by BLAST analysis, with the major tLST genes being responsible for the homeostasis module. However, WGS showed the absence of stx genes associated with tLST-positive isolates, albeit with virulence and resistance genes found in extraintestinal pathogenic E. coli (ExPEC).

CONCLUSION

Our findings demonstrate the presence of heat-resistant E. coli as well as confirm some tLST genes in E. coli isolated from Brazilian beef.

摘要

目的

对巴西牛肉中分离出的大肠杆菌和产志贺毒素大肠杆菌（STEC）进行分析，以确定其耐热性和可传播应激耐受基因座（tLST）的存在情况。

方法和结果

对 22 株先前从牛肉中分离并通过 PCR 鉴定为 STEC 的 STEC 进行了不同的耐热性生存挑战（60°C 和 71°C）。此外，还选择了 3 个 tLST 阳性和 1 个 tLST 阴性的 PCR 阳性分离株进行 WGS 分析。表型结果表明，3/22（13.64%）具有耐热性，12/22（54.54%）中度耐热，7/22（31.82%）对热处理敏感。WGS 分析显示，3 株耐热分离株的 tLST 与 BLAST 分析的相似度高达 80%和 42%，主要 tLST 基因负责体内平衡模块。然而，WGS 显示与 tLST 阳性分离株相关的 stx 基因缺失，尽管在肠外致病性大肠杆菌（ExPEC）中发现了毒力和耐药基因。