摘要

       产志贺毒素大肠杆菌 (STEC) 是一种重要的人畜共患食源性病原体，可引起与人类感染相关的急性胃肠道症状。在这项研究中，我们对 2010 年至 2016 年在中国东南部的 816 份零售生肉中分离出的 49 株 STEC 菌株的血清型、毒力相关基因、系统发育组、抗生素抗性和生物膜形成能力进行了表征。这些分离株属于 33 个不同的 O:H 血清型，其中 O157:H7（12.24%，6/49）是最常见的血清型。此外，22.45% (11/49) 的分离株属于最常与人类感染有关的“前六名”血清型。在研究的 11 个毒力相关基因中，stx2 (71.43%, 35/49) 是最普遍的毒力因子，87.76% (43/49) 的分离株携带两种或更多类型的毒力因子。 B1 (55.10%, 27/49) 和 D (28.57%, 14/49) 系统发育组在分离株中占主导地位，而没有菌株属于 B2 组。共有 59.18% (29/49) 的分离株对 16 种测试的抗微生物药物中的 13 种耐药，耐药率从头孢他啶和氯霉素的 4.08% (2/49) 到链霉素的 46.94% (23/49) 不等。我们检测到 30 个抗生素抗性基因中的 8 个（tetA、tetB、strA、strB、gyrA、floR、sulI 和 sulII），这些分离株的表型和基因型之间存在明显的错配。大多数菌株 (87.76%, 43/49) 产生生物膜，23.26% (10/43) 被归类为高生产者。总之，中国东南地区零售的生肉含有 STEC，具有多种血清型、毒力相关基因、抗菌素耐药性和生物膜形成能力，其中一些对消费者构成潜在的健康风险。

       Shiga toxin-producing Escherichia coli (STEC) is an important zoonotic foodborne pathogen that can induce acute gastrointestinal symptoms related to human infection. In this study, we characterized 49 STEC strains isolated from 816 retail raw meats from 2010 to 2016 in Southeast China for their serotype, virulence-associated genes, phylogenetic group, antibiotic resistance, and biofilm-forming ability. These isolates belonged to 33 divergent O: H serotypes, among which O157: H7 (12.24%, 6/49) was the most common serotype. Moreover, 22.45% (11/49) isolates belonged to the “top six” serotypes most frequently implicated in human infections. Among the 11 virulence-associated genes studied, stx2 (71.43%, 35/49) was the most prevalent virulence factor, with 87.76% (43/49) of isolates carrying two or more types of virulence factors. The B1 (55.10%, 27/49) and D (28.57%, 14/49) phylogenetic groups were predominant among isolates, whereas no strain belonged to group B2. A total of 59.18% (29/49) of isolates were resistant to 13 out of 16 tested antimicrobials, with resistance rate ranging from 4.08% (2/49) for both ceftazidime and chloramphenicol to 46.94% (23/49) for streptomycin. We detected eight out of 30 antibiotic-resistance genes (tetA, tetB, strA, strB, gyrA, floR, sulI, and sulII), with obvious mismatch between the phenotypes and genotypes of these isolates. Most strains (87.76%, 43/49) produced biofilms and 23.26% (10/43) were categorized as high producers. In conclusion, raw meats retailed in Southeast China contain STEC with multifarious serotypes, virulence-associated genes, antimicrobial resistance and biofilm-forming ability, some of which pose potential health risks to consumers.

https://www.sciencedirect.com/science/article/abs/pii/S0956713521001997