Monma Chie, Hatakeyama Kaoru, Obata Hiromi, Yokoyama Keiko, Konishi Noriko, Itoh Takeshi, Kai Akemi
Department of Microbiology, Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
Department of Microbiology, Tokyo Metropolitan Institute of Public Health, Tokyo, Japan.
J Clin Microbiol. 2015 Mar;53(3):859-67. doi: 10.1128/JCM.02859-14. Epub 2015 Jan 7.
The epidemiological and bacteriological investigations on four foodborne outbreaks caused by a new type of enterotoxin-producing Clostridium perfringens are described. C. perfringens isolated from patients of these outbreaks did not produce any known enterotoxin and did not carry the C. perfringens enterotoxin gene. However, the culture filtrates of these isolates induced the accumulation of fluid in rabbit ileal loop tests. The molecular weight of the new enterotoxin may be between 50,000 and 100,000, although the known C. perfringens enterotoxin is ca. 35,000. This new enterotoxin was heat labile, and its biological activities were inactivated by heating for 5 min at 60°C. The new enterotoxin was sensitive to pH values higher than 11.0 and protease treatment but was resistant to trypsin treatment. These results suggest that the new enterotoxin may be a protein. Although C. perfringens enterotoxin induced morphological changes in Vero cells, the changes induced by the new enterotoxin differed from those by the known C. perfringens enterotoxin. The new enterotoxin also induced morphological changes in L929 cells, whereas the known C. perfringens enterotoxin did not, because L929 cells lacked an appropriate enterotoxin receptor. Although C. perfringens enterotoxin is recognized as the only diarrheagenic toxin responsible for C. perfringens foodborne outbreaks, the results of the present study indicate that C. perfringens isolated from these four outbreaks produced a new type of enterotoxin.
本文描述了对由一种新型产肠毒素产气荚膜梭菌引起的四起食源性疾病暴发进行的流行病学和细菌学调查。从这些暴发事件患者身上分离出的产气荚膜梭菌不产生任何已知的肠毒素，也未携带产气荚膜梭菌肠毒素基因。然而，这些分离株的培养滤液在兔回肠袢试验中可诱导液体蓄积。尽管已知产气荚膜梭菌肠毒素的分子量约为35,000，但这种新型肠毒素的分子量可能在50,000至100,000之间。这种新型肠毒素对热不稳定，在60°C加热5分钟可使其生物活性丧失。该新型肠毒素对pH值高于11.0及蛋白酶处理敏感，但对胰蛋白酶处理具有抗性。这些结果表明，新型肠毒素可能是一种蛋白质。虽然产气荚膜梭菌肠毒素可诱导Vero细胞发生形态学变化，但新型肠毒素诱导的变化与已知产气荚膜梭菌肠毒素诱导的变化不同。新型肠毒素也可诱导L929细胞发生形态学变化，而已知产气荚膜梭菌肠毒素则不能，因为L929细胞缺乏合适的肠毒素受体。尽管产气荚膜梭菌肠毒素被认为是导致产气荚膜梭菌食源性疾病暴发的唯一致腹泻毒素，但本研究结果表明，从这四起暴发事件中分离出的产气荚膜梭菌产生了一种新型肠毒素。
