Ecology of thermostable direct hemolysin-producing Vibrio parahaemolyticus at the Southwest Islands.

本文对西南诸岛和西日本发现产热性直接溶血素（TDH）副溶血性弧菌的河口地理条件进行了调查。在许多被检查的河口发现了腹足类，尽管河口的咸淡水区域似乎太短，无法在西南群岛和爱爱县和静冈县的河口的腹足类中保存产生tdh的菌株。在河口采集腹足动物，怀疑其体内保存有产tdh菌株。在爱媛县和高知县获得了关于prahaemolyc弧菌食物中毒暴发的信息，以便在那里进行腹足类动物的搜索和从腹足类动物中产生tdh的菌株的检测试验。在河口收集的腹足类动物被带到实验室。取腹足动物消化道，匀浆，在碱性蛋白胨水中结合tdh-引物聚合酶链反应，用最可能数法检测产tdh菌株的水平。产tdh菌株在Sozu河口的sowerbianus中检测到19株/g，在爱远县Sozu和Kamo河口的retropictus中检测到a和600株/g，而在其他河口的样品中均未检测到产tdh菌株。从我们的观察结果可以看出，产tdh菌株是在包括逆转录弧菌和梭氏弧菌在内的幼年腹足类胃足动物高密度分布的环境条件下在河口检测到的。在河口底部可以看到含有大量有机物的泥质沉积物，低潮时还能看到低盐度的微咸水。

Geographical conditions of estuaries where thermostable direct hemolysin(TDH)-producing strains of Vibrio parahaemolyticus have been detected from neritid gastropods were examined at Southwest Islands and West Japan. The gastropods were found at many estuaries examined, though brackish water area of the estuaries seemed to be too short for TDH-producing strains to be preserved in the gastropods at estuaries of Southwest Islands and of Ehime and Shizuoka Prefectures. The gastropods were collected at estuaries where TDH-producing strain was suspected to be preserved in the gastropods. Informations on the outbreaks of Vibrio prahaemolyticus-food poisoning were obtained at Ehime and Kochi Prefectures so that the search of the gastropods and the detection trials of TDH-producing strains from the gastropods were done there. The gastropods collected at estuaries were carried to the laboratory. Alimentary tracts were removed from the gastropods, homogenized and examined the level of TDH-producing strains using most-probable-number method in alkaline peptone water combined with Polymerase chain reaction with tdh-primers.TDH-producing strain was detected at a level of 19/g from C.sowerbianus at Sozu estuary and of A and 600/g from C.retropictus at Sozu and Kamo estuaries in Ehime Prefecture, respectively, but not from any samples at other estuaries examined..From our observations, TDH-producing strain was concluded to be detected at the estuaries in the environmental conditions that juvenile neritid gastropods including C.retropictus and C.sowerbianus range at high density, that muddy sediments containing high level of organic matter are seen at the bottom of the estuary and that brackish water with low salinity remains at the low tide.