Attenuated Legionella pneumophila Survives for a Long Period in an Environmental Water Site
Figure 2
Intracellular growth of environmental strains from Ashiyu foot spa 2. (a) THP-1 cells were infected with L. pneumophila strains at an MOI of 1 for 1 h. Then medium was changed to gentamicin-containing (50 μg/mL) medium and incubated for 1 h at 37°C. After incubation for particular time, the infected cells were washed with RPMI 1640 medium, followed by lysis with cold distilled water. CFU counts were determined by serial dilution on BCYE. (b) D. discoideum was infected with L. pneumophila strains at an MOI of 1 for 1 h. Then medium was changed to gentamicin-containing (50 μg/mL) medium and incubated for 1 h at 37°C. After incubation for particular time, the infected cells lysed with 0.02% saponin. CFU counts were determined by serial dilution on BCYE. All values represent the average and the standard deviation for three identical experiments. Statistically significant differences compared with Togus-1 are indicated by asterisks (, P < 0.01).