Prevalence and diversity of enterotoxin genes with genetic background of Staphylococcus aureus isolates from different origins in China
Prevalence and diversity of enterotoxin genes with genetic background of Staphylococcus aureus isolates from different origins in China
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DOI：
10.1016/j.ijfoodmicro.2015.07.018
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发表时间：
2015-10-15
影响因子：
5.4
通讯作者：
Wu, Yantao
中科院分区：
文献类型：
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作者：
Chao, Guoxiang;Bao, Guangyu;Wu, Yantao
葡萄球菌肠毒素 (SE) 会诱发毒素介导的疾病，例如食物中毒。在本研究中，对来自不同来源的 568 个分离株进行了 18 个 SE 基因的流行率测试，并进行了 spa 分型。此外，我们根据选定的 250 个分离株的多位点序列分型 (MIST)、spa 和葡萄球菌盒式染色体 mec (SCCmec) 分型，描述了 SE 基因分布与分子克隆之间的关系。来自不同来源的大约 54.40% 的分离株含有一种或多种 SE 基因，形成 120 个不同的基因谱。七个基因：sea、seb、seg、seo、sem、seq 和 sel 的检测频率较高。人类、动物和食源来源的分离株中 SE 基因的分布与环境分离株之间存在显着差异（P < 0.01）。食源性和人源分离株中的经典SE基因均显着高于动物源分离株（P < 0.01），而egc簇基因和其他基因在人、动物和食源分离株中的流行率相似（P > 0.05）。我们鉴定了两个重要的基因簇：sea-sek-seq（与医院获得性（HA）耐甲氧西林金黄色葡萄球菌（MRSA）-III密切相关）和egc簇（占所有基因的近一半）。大约71%的分离株可以通过spa进行分型，产生103个spa类型，其中18个spa类型是主要类型。在克隆复合体（CC）239（来自人类的重要亚洲 HA-MRSA-III 克隆）中，几乎所有分离株都具有完整或部分的 sea-sek-seq 簇；主要的 SPA 类型是 t030 和 t037。 CC630是中国重要的新群落相关（CA）MRSA-V CC，仅观察到散发的SE基因，三种主要的spa类型：t4549、t2196和t377。与其他基因共存的egc簇存在于CG、CC9、CC1281、CC1301、COO和序列类型(ST)25的分离株中，但在CC239、CC59、CC7和CC88的分离株中完全不存在。结果说明了不同来源的金黄色葡萄球菌分离株在 SE 基因方面的遗传克隆多样性和同一性，并强调了 SE 基因或基因簇与 CC、spa 和 MRSA 克隆之间的相关性。食源性和人类来源的分离株是经典葡萄球菌食源性中毒的主要潜在原因，而含有新基因的分离株则是食品安全的新的潜在危害。 (C) 2015 年由 Elsevier B.V. 出版
Staphylococcal enterotoxins (SE) induce toxin-mediated diseases, such as food poisoning. In the present study, 568 isolates from different sources were tested for the prevalence of 18 SE genes and performed spa typing. In addition, we characterized the relationships between the distribution of SE genes and molecular clones based on multilocus sequence typing (MIST), spa and staphylococcal cassette chromosome mec (SCCmec) typing in selected 250 isolates. Approximately 54.40% of the isolates from different sources harbored one or more SE genes forming 120 distinct gene profiles. Seven genes, sea, seb, seg, seo, sem, seq, and sel were more frequently detected. The distributions of the SE genes among the isolates from human, animals, and foodbome origins were highly different with isolates from environments (P < 0.01). The classic SE genes in both foodborne and human origin isolates were significantly higher than that in animal origin isolates (P < 0.01), whereas the prevalence of genes of egc cluster and the other genes was similar in human, animal, and foodbome origin isolates (P > 0.05). We identified two important gene clusters, sea-sek-seq, which is closely related to hospital-acquired (HA) methicillin-resistant Staphylococcus aureus (MRSA)-III, and the egc cluster, which accounts for nearly half of all genes. Approximately 71% isolates could be typed by spa, yielding 103 spa types, of which 18 spa types were primary types. In clonal complex (CC) 239, an important Asian HA-MRSA-III clone from humans, nearly all isolates harbored complete or partial sea-sek-seq cluster; the main spa types were t030 and t037. In CC630, an important new community-associated (CA) MRSA-V CC in China, only sporadic SE genes, three main spa types, t4549, t2196, and t377 were observed. The egc cluster coexisting with other genes was present in isolates of CG, CC9, CC1281, CC1301, COO and sequence type (ST) 25, but completely absent in isolates of CC239, CC59, CC7, and CC88. The results illustrate the genetic clonal diversity and the identity of S. aureus isolates from different sources with respect to SE genes and highlight a correlation between SE genes or gene clusters and CCs, spa, and MRSA clones. The foodborne and human origin isolates were the main potential causes of classic staphylococcal foodborne poisonings, whereas isolates harboring novel genes were new potential hazards to food safety. (C) 2015 Published by Elsevier B.V.