Figure 2
Survival characteristics of novel and previously identified mutants validated in the mouse splenic clearance model of infection. To confirm attenuated virulence several of the mutants were evaluated for survival in the mouse splenic clearance model using a 1:1 mixture of parental wild-type (B. melitensis 16 M) and mutant to inoculate mice (n = 10 per group) with an overall dose of 5 × 106 cfu. At one (white bars) and four weeks (black bars) post inoculation spleens were excised from the mice, and recovery of the B. melitensis 16 M and the mutant were determined as described in the Materials and Methods. Recovery of Brucella is presented as a Survival Ratio (CFU 16 M/CFU mutant) corrected for variation in the input ratio in the inoculum calculated the same way.