The Mechanism of Resistance to Free Residual Chlorine and Pathogenesity in Protomonas extorquens Isolated from Drinking Tank-Water

点击翻译按钮获取中文摘要

A fundamental study was conducted to elucidate the mechanism of resistance to chlorine exhibited by Protomonas extorquens, which was isolated from the drinking water tank at a high frequency.Distribution of Protomonas extorquens, chlorine resisitant gram-negative rod bacteria, was investigated in Tokyo and Tsukuba Science City.It was isolated by using standard agar and LNP agar medium culture for 7 days at 25 ﾟC.Protomonas extorquens was highly detected from tap water, drinking tank-water (78.9%)and direct-water(64.3%),all over the city.Furthermore,it was found in 40% of swimming pool water, in which free residual chlorine-concentration was high, 0.6-1.0 mg . 1^<-1>.However, it was found little in natural environmental pond,lake and river.The Chlorine-sensitive wild strain and chlorine-resistant mutant strain of Protomonas extorquens were examined for biotypes, antimicrobial susceptibility, bacterial fatty acid composition, morphology, structure of the superficial layer of the cell and for the presence of plasmids.Electron microscopic observations showed that the resisitant strain microbes have thick and solid outer-membranes. This strengthened outer membrane was considered to be related with the resistance of this bacterium to chlorine. Plasmids were not detected in any tested strain.Acute pathogenisity of this bacteria to nude mouse was examined. Noun of them was died but their weight decreased in the group injected(i.P.) bacterial cells.Many bio-cells were isolated from intraperitoneum after 3 days injection.Protomonas extorquens seems to have a significant role in immunocompromised hosts.