FIG. 3.

Coculture of L. pneumophila with H. vermiformis amoebae. Wild-type (solid bars) and NU269 (open bars) strains were mixed at an MOI of 0.1 to amoebae that were treated or not with 25 or 50 μM DIP, and then numbers of bacteria within the cocultures were sampled at 0 and 48 h postinoculation. Data represent the mean and standard deviation from triplicate samples. The experiment was repeated in triplicate with similar results. Significant differences between the wild-type and mutant strains were observed in the 48-h cultures containing 50 μM DIP (Student's t test, P < 0.005).