FIG. 1.

Survival of noncapsulated K. pneumoniae strains in the lungs of BALB/c mice (normal and immunosuppressed). Normal and CP-treated BALB/c mice were inoculated with 4 × 10⁴ CFU/mouse of the K50/n, K55/n, K2/n, and K21a/n Klebsiella strains. Mice were sacrificed 72 h after bacterial inoculation, the lungs were homogenized, and the CFU were counted. The controls consisted of mock infections without bacteria. The results are expressed as means and standard deviations calculated from three different experiments (five animals per group). Statistical differences (as determined by an ANOVA test) between the O1 and O3 serotypes were found for normal (P < 0.024) and CP-treated (P < 0.02) mice.