PATHOGENICITY OF SALMONELLA IN ENVIRONMENTS

沙门氏菌是日本10多年来食源性疾病的主要微生物之一，其致病性在实验室和环境领域都进行了研究。对一株致病性沙门氏菌（Salmonella Typhimurium; STM）在不同pH、等渗性或盐浓度的水中的存活能力进行了研究，发现STM在稳定期比对数期更稳定。对东京多摩河河水的调查表明，该河流的上中游沿着均存在肠道沙门氏菌（Salmonella enteritrification，SE）污染，所有分离的SE克隆对经口感染的BALB/c小鼠均表现出毒力。此外，在鸡场环境中也分离到致病性SE，如空气中的灰尘、鸡舍墙壁等。对这些SE的分析表明，约1/2的分离克隆对小鼠具有致病性，并且SE的一系列蛋白条带密切相关，MAW为20-30 kDa。这些结果表明，大部分（但不是全部）环境中的沙门氏菌具有致病性，其毒力的表达可能受一系列分子量为20- 30 kDa的沙门氏菌蛋白以及沙门氏菌生长阶段的调控。

Pathogenicity of Salmonella, which has been one of the major microbes for food-born diseases in Japan for these more than 10 years, was studied both in laboratory and in environmental fields. Viability of a pathogenic Salmonella of a clinical isolate (Salmonella Typhimurium; STM) was examined in water of different compositions with pH, isotonicity or salt, and found that STM grown in a stationary phase was much more stable than that in a logarithmic phase. Survey of the river water of Tama River in Tokyo revealed that Salmonella Enteritidis (SE) was contaminated along with the up-and middle streams of this river, and that all of the isolated clones of SE shoed virulence to BALB/c mice infected p.o. Furthermore, pathogenic SE was also isolated in environment of chicken farms, such as dust in air or wall of the chicken house. Analysis of these SE showed that about 1/2 of the isolated clones were pathogenic to mice, with close correlation of a series of protein bands of SE of MAW 20-30 kDa. These results suggest that most, but not all, of the environmental SE either in river water or in chicken farm possess pathogenicity, and that the expression of the virulence might be regulated by a series of Salmonella proteins of MW 20-30kDa and also by growth phases of Salmonella.