从埃及不同来源分离的非-O157 肠出血性大肠杆菌的特性。

Characterization of non-O157 enterohemorrhagic Escherichia coli isolated from different sources in Egypt.

机构信息

Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt.

出版信息

BMC Microbiol. 2024 Nov 21;24(1):488. doi: 10.1186/s12866-024-03636-3.

DOI:10.1186/s12866-024-03636-3

PMID:39574016

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11580514/

Abstract

BACKGROUND

Enterohemorrhagic Escherichia coli (EHEC) O157 is implicated in serious food and water-borne diseases as hemorrhagic colitis (HC), and the potentially fatal hemolytic uremic syndrome (HUS). However, new players of non-O157 EHEC have been implicated in serious infections worldwide. This work aims at analyzing serotype and genotypic-based virulence profile of EHEC local isolates.

METHODS

A total of 335 samples were collected from different sources in Egypt. E. coli was isolated and subjected to serotyping. Non-O157 EHEC isolates were tested for virulence genes using PCR, phenotypic examination, phylogenetic typing, and molecular investigation by ERIC typing and MLST to disclose genetic relatedness of isolates. A heat map was used to identify potential associations between the origin of the isolates, their phenotypic and genotypic characteristics.

RESULTS

A total of 105 out of 335 isolates were identified as E. coli. Surprisingly, 49.5% of these isolates were EHEC, where O111, O91, O26 and O55 were the most prevalent serotypes including 38.46% from stool, 21.15% urine, 23.1% cheese, 9.62% meat products, 3.85% from both yogurt and sewage water. Screening 15 different virulence genes revealed that sheA, stx2 and eae were the most prevalent with abundance rates of 85%, 75% and 36%, respectively. Fifteen profiles of virulence gene association were identified, where the most abundant one was stx2/sheA (19%) followed by stx2/stx2g/sheA/eae (11.5%). Both stx2/sheA/eae and stx2/stx2g/sheA were equally distributed in 9.6% of total isolates. Phylogenetic typing revealed that pathogenic phylogroups B2 and D were detected among clinical isolates only. Forty-six different patterns were detected by ERIC genotyping. MLST resolved three sequence types of ST70, ST120 and ST394. The heat map showed that 21 isolates were of 70% similarity, 9 groups were of 100% clonality.

CONCLUSIONS

The prevalence of non-O157 EHEC pathotype was marginally higher among the food isolates compared to the clinical ones. The endemic ST120 was detected in cheese, necessitating crucial measures to prevent the spread of this clone. Clinical EHEC isolates exhibited a higher score, and combination of virulence genes compared to food and sewage water isolates, thereby posing a significant public health concern.

摘要

背景

肠出血性大肠杆菌（EHEC）O157 与严重的食源性和水源性疾病有关，包括出血性结肠炎（HC）和潜在致命性溶血性尿毒综合征（HUS）。然而，新出现的非 O157 EHEC 也与全球严重感染有关。本研究旨在分析本地分离株的血清型和基于基因型的毒力特征。

方法

从埃及不同来源采集了 335 份样本。分离出大肠杆菌并进行血清分型。使用 PCR、表型检测、系统进化分型以及 ERIC 分型和 MLST 进行分子研究，检测非 O157 EHEC 分离株的毒力基因，以揭示分离株的遗传相关性。使用热图确定分离株的来源、表型和基因型特征之间的潜在关联。

结果

335 份标本中共有 105 份被鉴定为大肠杆菌。令人惊讶的是，其中 49.5%为 EHEC，最常见的血清型为 O111、O91、O26 和 O55，包括 38.46%来自粪便、21.15%来自尿液、23.1%来自奶酪、9.62%来自肉产品、3.85%来自酸奶和污水。筛选 15 种不同的毒力基因显示，sheA、stx2 和 eae 最为普遍，丰度分别为 85%、75%和 36%。共发现 15 种毒力基因关联谱，其中最为丰富的是 stx2/sheA（19%），其次是 stx2/stx2g/sheA/eae（11.5%）。stx2/sheA/eae 和 stx2/stx2g/sheA 在总分离株中各占 9.6%。系统进化分型显示，临床分离株中仅检测到致病性菌系 B2 和 D。ERIC 基因分型检测到 46 种不同模式。MLST 鉴定出 ST70、ST120 和 ST394 三种序列型。热图显示 21 个分离株相似度为 70%，9 个组相似度为 100%。