FIG. 6.

Elimination of L. pneumophila from the lungs of intranasally inoculated mice. A/J mice were inoculated with 10⁶ cells of L. pneumophila. In each experiment, three mice were used for the test at the 1-h infection point and four mice each were used for the 24- and 48-h infection points. At the time points indicated, the mice were sacrificed and the number of L. pneumophila in the lungs was determined as described in Materials and Methods. The number of bacteria at 1 h postinoculation was set at 1, and the numbers at the 24- and 48-h time points are presented as the relative ratio. Shown here are the results for the wild isolate 80-045 (squares), the laiA mutant LAM0101 (circles), and the laiA-complemented strain LAM0102 (triangles). Results indicate the means ± standard deviations of the bacterial counts at the indicated time point. The numbers of LAM0101 bacteria at the 24- and 48-h time points are significantly less than those of 80-045 and LAM0102. Three independent experiments showed similar results.