Attenuated Legionella pneumophila Survives for a Long Period in an Environmental Water Site

Figure 4

Biofilm formation of environmental strains from Ashiyu foot spa 2. (a), (b) Each strain was inoculated into 96-well plates. After 2-day (a) or 4-day (b) incubation, biofilm mass was stained with crystal violet solution. (c) To quantify biofilm mass, after staining, the dye was solubilized in 33% glacial acetic acid. The optical density at 570 nm of the resulting solution was determined with the microplate reader. 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).

(a)

(b)

(c)