FIG. 7.

Persistence of nonpolar mutants in spleens of BALB/c mice. Each dot represents CFU recovered from a single mouse; the mean number of CFU in each group is indicated by a horizontal line. Asterisks indicate statistical significance of each group compared to wild-type B. abortus, as determined by one-way analysis of variance followed by a Tukey-Kramer multiple comparison. (A) One week postinoculation. (B) Eight weeks postinoculation. The horizontal line across each graph indicates the limit of detection.