Studies of development of method for detection of aquatic pathogenic bacteria in viable but non-culturable stage and their ecology.

有些细菌种类，如芽孢杆菌属和梭状芽孢杆菌属，通过形成孢子来适应不良环境。近年来人们认为，在自然环境中，细菌细胞除了形成孢子外，还有一种对环境条件变化的耐受机制，即存活但不可培养（VNC）阶段。有些水生细菌对人有致病性，其中许多细菌在常规培养基上培养可检出，用于临床诊断，但有些细菌不能检出。这些无法检测的细菌应该以VNC的形式存在。我们试图建立一种检测VNC的方法，并将其应用于生态学研究，特别是对食物中毒细菌副溶血性弧菌的生态学研究。建立了以弧菌侧鞭毛基因为引物进行聚合酶链反应的方法，并对其有效性进行了验证。尽管需要进行一些改进，但该方法被认为对检测VNC单元是有用的。并对弧菌进行了生态学研究，提出了选用选择性培养基进行生态学研究应注意的问题。

Some bacterial species such as genera Bacillus and Clostridium adapt against undesirable circumstances by spore formation. Recently it has been believed that a tolerant mechanism other than spore formation against change of environmental condition acts in natural environment, namely viable but non-culturable (VNC) stage of bacterial cells. Some of the aquatic bacteria are pathogenic for human and many of them can be detected by cultivation on/in usual media for clinical diagnostic, but some of them cannot. These undetectable bacteria are supposed to exist as VNC.We tried to develop method for detection of VNC and to apply it to ecological study, special emphasis on ecology of Vibrio parahaemolyticus, a food poisoning bacterium. A polymerase chain reaction method with primers induced from lateral flagellar gene of the vibrio was developed and its usefulness was tested. Although some improvements are necessary, the method is thought to be useful for detection VNC cells. Ecological study of the vibrio was also carried out and some points of problem in use of selective media to ecological study was suggested.