FIG 2 .

Virulence defects associated with ΔchiA are complemented in trans by the presence of wild-type L. monocytogenes. (A) Wild-type and ΔchiA strain mixed infections in mice. Swiss Webster mice were intravenously infected with 2 × 10⁴ total CFUs of a 1:1 mixture of the L. monocytogenes DP-L3903 (10403S with a silent Tn917-lac insertion conferring erythromycin resistance) and ΔchiA strains. After 72 h of infection, livers and spleens of infected mice were harvested and bacteria were enumerated. As a control, groups of mice were infected with a 1:1 mixture of wild-type L. monocytogenes strains with the DP-L3903 erythromycin-resistant strain. Each data point represents the competitive index or the ratio of ΔchiA CFU recovered to that of wild-type L. monocytogenes. Data shown are representative of at least 2 independent experiments. (B) Total CFU of wild-type and ΔchiA mutant strains recovered from each organ. Data shown are representative of at least 2 independent experiments.