FIG. 6.

Both hypo- and hyperresistant Lsp⁻ mutants are attenuated. The lspH66A and lspH142A alleles, hypo- and hyperresistant to zinc starvation, respectively, were used to replace the chromosomal copy of lsp in the wild-type strain (WT). The virulence of the resulting mutants (LspH66A and LspH142A) was then compared with that of the wild type in the murine model of subcutaneous infection. The data shown are from two independent experiments. Each symbol represents the area of ulcer observed in an individual mouse, and the horizontal bar indicates the mean value obtained for the set of 10 mice. The mutants were both significantly less virulent than the wild type compared on the basis of lesion area (P = 0.005 for LspH66A; P = 0.003 for LspH142A).