Replication of the MtΔmce2R mutant, the wild type and complemented strains in mouse lungs after intratracheal inoculation. Groups of mice were infected by intratracheal injection of wild type (white bars), MtΔmce2R (black bars), MtΔmce2RComp (grey bars). At 1, 26 and 35 days post-infection, mice were sacrificed and viable bacteria present in the lungs were recovered. The results are expressed as the mean number of CFUs ± standard deviations in five mice. These data are based on one of two independent experiments with similar results. *(p < 0.05) significantly different from values of the wild type strain.