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

在西南群岛和日本西部的腹足类动物中检测到耐热的副溶血性弧菌产生直接溶血素(TDH)菌株的河口地理条件进行了研究。在被检查的许多河口都发现了腹足类，尽管河口的微咸水区域似乎太短，无法保存在西南群岛以及爱美县和静冈县的河口的腹足类中。腹足类是在河口采集的，怀疑腹足类中保存了产生TDH的菌株。在爱美县和高知县获得了关于副溶血性弧菌食物中毒暴发的信息，以便在那里进行腹足类的搜索和腹足类产生TDH的菌株的检测试验。在河口采集的腹足类被带到实验室。取腹足类消化道组织匀浆，用最大可能数法结合聚合酶链式反应和TDH型引物，在碱性蛋白调水中检测到TDH产生菌。在SOZO河口苏氏沼虾和爱美县SOZU和KAMO河口的反枝线虫中分别检出19株和600株TDH产生菌，而在其他河口的样品中均未检测到TDH产生菌。根据我们的观察，在高密度的环境条件下，河口可检测到TDH菌。在河口底部发现了高有机质的泥质沉积物，低潮时仍有低盐度的微咸水。

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.