Association of beta2 toxin production with Clostridium perfringens type A human gastrointestinal disease isolates carrying a plasmid enterotoxin gene
Association of beta2 toxin production with Clostridium perfringens type A human gastrointestinal disease isolates carrying a plasmid enterotoxin gene
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DOI：
10.1111/j.1365-2958.2005.04573.x
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发表时间：
2005-05-01
影响因子：
3.6
通讯作者：
McClane, BA
中科院分区：
文献类型：
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作者：
Fisher, DJ;Miyamoto, K;McClane, BA
携带肠毒素（cpe）基因的A型产气荚膜梭菌是人类胃肠道疾病的重要原因，包括食物中毒、抗生素相关性腹泻（AAD）和散发性腹泻（SD）。目前的研究利用聚合酶链反应 (PCR) 确定，编码最近发现的 beta2 毒素的 cpb2 基因存在于 < 15% 的食物中毒分离株中，这些分离株通常携带染色体 cpe 基因。然而，> 75% 的 AAD/SD 分离株（通常携带质粒 cpe 基因）通过 PCR 检测出 cpb2(+)。蛋白质印迹分析表明，> 97% 的 cpb2(+)/cpe(+) AAD/SD 分离株可以产生 CPB2。其他 PCR 分析、测序研究和脉冲场凝胶电泳实验确定，当 IS1151 序列存在于 cpe 下游时，AAD/SD 分离株在同一质粒上携带 cpb2 和 cpe，但 cpb2 和 cpe 位于 AAD/SD 分离株中的不同质粒上，其中 IS1470 样序列存在于 cpe 下游。这些分析还表明，AAD/SD 分离株可以产生两种不同的 CPB2 变体（称为 CPB2h1 或 CPB2h2），具体取决于其 cpe 基因下游是否存在 IS1470 样序列或 IS1151 序列。 CPB2h1 对 CaCo-2 细胞的细胞毒性比 CPB2h2 强 10 倍。总的来说，这些结果表明 CPB2 可能是产气荚膜梭菌肠毒素 (CPE) 相关 AAD/SD 中的辅助毒素。
Clostridium perfringens type A isolates carrying an enterotoxin (cpe) gene are an important cause of human gastrointestinal diseases, including food poisoning, antibiotic-associated diarrhoea (AAD) and sporadic diarrhoea (SD). Using polymerase chain reaction (PCR), the current study determined that the cpb2 gene encoding the recently discovered beta2 toxin is present in < 15% of food poisoning isolates, which typically carry a chromosomal cpe gene. However, > 75% of AAD/SD isolates, which usually carry a plasmid cpe gene, tested cpb2(+) by PCR. Western blot analysis demonstrated that > 97% of those cpb2(+)/cpe(+) AAD/SD isolates can produce CPB2. Additional PCR analyses, sequencing studies and pulsed field gel electrophoresis experiments determined that AAD/SD isolates carry cpb2 and cpe on the same plasmid when IS1151 sequences are present downstream of cpe, but cpb2 and cpe are located on different plasmids in AAD/SD isolates where IS1470-like sequences are present downstream of cpe. Those analyses also demonstrated that two different CPB2 variants (named CPB2h1 or CPB2h2) can be produced by AAD/SD isolates, dependent on whether IS1470-like or IS1151 sequences are present downstream of their cpe gene. CPB2h1 is similar to 10-fold more cytotoxic for CaCo-2 cells than is CPB2h2. Collectively, these results suggest that CPB2 could be an accessory toxin in C. perfringens enterotoxin (CPE)-associated AAD/SD.