Himar interruption of the erythritol locus has varying effect on virulence. The virulence of mutants interrupted in different genes of the erythritol locus were evaluated in the mouse splenic clearance model using mixtures (approximately 1:1) of B. melitensis 16 M and individual mutants containing interruptions in either eryB or eryC as indicated. Recovery of the parental wild-type and mutant were determined one week after infection by plating spleen homogenate on TSA with and without kanamycin as described in Materials and Methods. The ratio of wild-type to mutant recovered is corrected for variation in the input ratio and the final value is expressed as a ratio of 16 M to mutant recovered as described in Materials and Methods. The values shown reflect the ratios recovered plotted on a log scale. Differences in the average values were evaluated for significance via one-way ANOVA with Kruskal-Wallis test followed by Dunn's multiple comparisons between all groups p-value <0.0045 (**).