FIG. 1.

Survival of the B. abortus S19 ΔvjbR::Kan mutant in J774A.1 macrophages. Wild-type strain 2308, S19, and the B. abortus S19 ΔvjbR::Kan mutant were used to infect J774A.1 macrophages at an MOI of 1:100. After 30 min of incubation followed by 1 h of treatment with gentamicin, infected macrophages were further incubated for 0 or 48 h. Treated cells were lysed, serially diluted, and plated on TSA or TSA-kanamycin plates for CFU determination. The results are represented as the means of three independent experiments ± SEMs. Statistical differences were analyzed by ANOVA followed by Tukey's posttest comparing all groups to one another. *, P < 0.001 compared to the 2308 control; #, P < 0.05 compared to S19.