FIG. 1.

Growth of L. pneumophila serogroup 1 strains F889 (A) and F2111 (B) in guinea pig alveolar macrophages versus day of incubation after initiation of infection. The drugs were added on day 1 and removed by washing on day 3. All points represent the means of triplicate wells, each plated in duplicate; the error bars represent 95% confidence intervals, which unless shown were smaller than the height of the symbol representing the mean. ▪, saline control; □, tigecycline at 0.25 μg/ml; ⋄, tigecycline at 1 μg/ml; ♦, tigecycline at 2 μg/ml; ○, azithromycin at 0.25 μg/ml; •, azithromycin at 1 μg/ml; ▿, erythromycin at 1 μg/ml. The data for tigecycline at 0.25 μg/ml are not shown in panel A for greater clarity, as its effect was nearly identical to that of tigecycline at 1 μg/ml.