|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 1999 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1998 : ¥2,200,000 (Direct Cost : ¥2,200,000)
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.