FIG. 1.

Cytopathogenicities of the L. pneumophila wild-type strain AA100 and the isogenic insertion mutants to U937 macrophage-like cells 38 h postinfection and to A. polyphaga 30 h postinfection. The data are representative of three to five independent experiments, performed in triplicate, and the error bars represent standard deviations. The five phenotypic groups based on intracellular growth kinetics (shown in Fig. 2) are indicated.