FIG 8.

Heme is not available as an iron source to V. cholerae in the infant mouse intestinal tract. (A) Relative fitnesses of wild-type O395 and EPV134 (O395 ΔhemA) were determined in vitro in LB supplemented with the indicated concentrations of heme. Each point represents a separate culture; lines indicate the means and standard deviations. (B) Relative fitness of wild-type O395 and EPV134 (O395 ΔhemA) was determined in vivo. Each circle indicates a separate infant mouse. Circles indicate the calculated competitive index in mice from which EPV134 was isolated (n = 7); EPV134 was not isolated from an additional 16 mice (not depicted). The competitive index (CI) was calculated by normalizing the output ratio to the input ratio of the two competing strains. Each data point represents one mouse, and the mean CI and standard deviation are represented by horizontal lines. A competitive index of <1 indicates a fitness defect for the hemA mutant under the condition.