| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2015: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Outline of Final Research Achievements |
Legionella spp. is known as a high-priority pathogen in microbial risk management in water distribution systems, and this investigation, therefore, attempted to determine risk factors of Legionella spp.. In particular, water samples from the faucets located in distribution systems via cisterns were taken to survey regrowth of Legionella spp. and free-living amoeba (FLA) and to check possibility of Legionella and heterotrophic bacteria regrowth in water with/without FLA after quenching chlorine residual. The regrowth or survival of Legionella spp. was tended to be higher in the unfiltered (FLA possibly living) water samples, while HPC was tended to increase in the filtered (FLA removed) samples. This result suggests that HPC can be escaped from FLA predation in filtered water samples, but that Legionella spp. prefers conditions with FLA to survive in water distribution systems. Also, in water with chlorine residual above 0.4 mg/L, no FLA detection was observed.
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