Figure 2.

Recovery of rough Brucella from the spleens of infected mice. Mice were infected with clonal populations of smooth or rough B. melitensis, or a mixture of smooth and rough B. melitensis. Bacterial colonization was evaluated at 1-week (A) and 8-weeks (B) post-infection. Mice infected with a clonal population of rough organisms cleared the infection as early as 1 week post-infection. In contrast, spontaneous rough mutants are recovered from mice infected with smooth strains (either clonal smooth strains or a mixture of smooth and rough strains) at both 1 and 8 weeks post-infection. The horizontal line above the x-axis represents the limit of detection. Differences between rough and smooth organisms are significant at p < 0.05.