NanH Is Produced by Sporulating Cultures of Clostridium perfringens Type F Food Poisoning Strains and Enhances the Cytotoxicity of C. perfringens Enterotoxin.
NanH Is Produced by Sporulating Cultures of Clostridium perfringens Type F Food Poisoning Strains and Enhances the Cytotoxicity of C. perfringens Enterotoxin.
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产气荚膜梭菌F型食物中毒菌株产孢培养物产生NanH并增强C.产气荚膜杆菌肠毒素
DOI：
10.1128/msphere.00176-21
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发表时间：
2021-04-28
期刊：
影响因子：
4.8
通讯作者：
McClane BA
中科院分区：
文献类型：
--
作者：
Li J;McClane BA
在美国，F型产气荚膜梭菌是第二种最常见的食源性疾病。产气荚膜梭菌肠毒素(CPE)是这次食物中毒(FP)的腹泻和痉挛症状的罪魁祸首。先前的研究表明，纳米唾液酸酶在体外可以增强CPE的活性。F型产气荚膜梭菌食物中毒(FP)菌株是最常见的食源性疾病之一。当F型FP菌株在肠道内产生孢子并产生产气荚膜梭菌肠毒素(CPE)时，就会产生这种FP，这种毒素是导致这种疾病的腹泻和腹部痉挛的原因。虽然产气荚膜梭菌可以产生多达三种不同的唾液酸酶，但目前的研究调查了FP菌株，这证实了先前研究的结果，即它们始终携带纳米H唾液酸酶基因，通常作为它们唯一的唾液酸酶基因。研究发现，NanH的产生与调查的F FP菌株的孢子培养有关，包括SM101(FP菌株的可转化衍生品)。在改良邓肯-强培养基(MDS)中生长的菌株SM101与产孢量相关的调节涉及Spo0A，但它不需要产孢量的完成。当SM101在MDS中培养时，NanH的产生对SM101的生长或产孢量都不是必需的。在这些MDS培养中，NanH在产孢母细胞中积累，直到它与CPE同时释放。由于当母细胞裂解释放成熟孢子时，CPE变为胞外，这表明母细胞裂解对NanH的释放也很重要。裂解产孢子菌培养上清液中纳米羟基磷灰石和环丙沙星的共存可增强环丙沙星对Caco-2细胞的杀伤作用。这一增强归因于NanH增加了CPE结合，并可用纯化的重组NanH复制。这些体外研究结果提示，NanH可能是FFP的一个辅助毒力因子。重要性F型产气荚膜梭菌在美国引起第二常见的细菌性食源性疾病。产气荚膜梭菌肠毒素(CPE)是这次食物中毒(FP)的腹泻和痉挛症状的罪魁祸首。先前的研究表明，纳米唾液酸酶在体外可以增强CPE的活性。虽然许多F型FP菌株不产生NaNI，但它们确实始终如一地产生NanH唾液酸酶。这项研究表明，与CPE一样，NanH是由产孢型F FP菌株产生的，然后在其产孢细胞溶解释放成熟孢子时释放到细胞外。在体外，NanH通过增加CPE与培养的Caco-2细胞的结合而增强CPE的细胞毒性。这种增强可能很重要，因为许多FFP菌株产生的CPE比在动物模型中引起肠道病理所需的(纯化形式)要少。因此，NanH代表了FFP的一个潜在的辅助毒力因子。
Clostridium perfringens type F strains cause the second most common bacterial foodborne illness in the United States. C. perfringens enterotoxin (CPE) is responsible for the diarrhea and cramping symptoms of this food poisoning (FP). Previous studies showed that NanI sialidase can enhance CPE activity in vitro. Clostridium perfringens type F food poisoning (FP) strains cause one of the most common foodborne illnesses. This FP develops when type F FP strains sporulate in the intestines and produce C. perfringens enterotoxin (CPE), which is responsible for the diarrhea and abdominal cramps of this disease. While C. perfringens can produce up to three different sialidases, the current study surveyed FP strains, which confirmed the results of a previous study that they consistently carry the nanH sialidase gene, often as their only sialidase gene. NanH production was found to be associated with sporulating cultures of the surveyed type F FP strains, including SM101 (a transformable derivative of a FP strain). The sporulation-associated regulation of NanH production by strain SM101 growing in modified Duncan-Strong medium (MDS) was shown to involve Spo0A, but it did not require the completion of sporulation. NanH production was not necessary for either the growth or sporulation of SM101 when cultured in MDS. In those MDS cultures, NanH accumulated in the sporulating mother cell until it was released coincidently with CPE. Since CPE becomes extracellular when mother cells lyse to release their mature spores, this indicates that mother cell lysis is also important for NanH release. The copresence of NanH and CPE in supernatants from lysed sporulating cultures was shown to enhance CPE cytotoxicity for Caco-2 cells. This enhancement was attributable to NanH increasing CPE binding and could be replicated with purified recombinant NanH. These in vitro findings suggest that NanH may be an accessory virulence factor during type F FP. IMPORTANCE Clostridium perfringens type F strains cause the second most common bacterial foodborne illness in the United States. C. perfringens enterotoxin (CPE) is responsible for the diarrhea and cramping symptoms of this food poisoning (FP). Previous studies showed that NanI sialidase can enhance CPE activity in vitro. While many type F FP strains do not produce NanI, they do consistently make NanH sialidase. This study shows that, like CPE, NanH is produced by sporulating type F FP strains and then released extracellularly when their sporulating cells lyse to release their mature spore. NanH was shown to enhance CPE cytotoxicity in vitro by increasing CPE binding to cultured Caco-2 cells. This enhancement could be important because many type F FP strains produce less CPE than necessary (in a purified form) to cause intestinal pathology in animal models. Therefore, NanH represents a potential accessory virulence factor for type F FP.