Fig. 8.
A V. cholerae ΔtcpA mutant is defective in colonizing the intestine of CL-treated adult mice. N16961 and its ΔtcpA mutant grown in LB were harvested and mixed at 1:1 ratio. A mixture of 1 × 109 CFU was inoculated via oral gavage into PBS-treated (control) or CL-treated mice (n = 6 per group). At 24 h post-infection, mice were sacrificed to measure bacterial colonization. a Viable cell numbers of V. cholerae cells (both N16961 and the ΔtcpA mutant). Aliquots of lysates (small intestine or cecum) were serially diluted for V. cholerae CFU counting on LB agar supplemented with 200 μg/mL SM. Values are displayed on a log scale as mean ± SEM for each group. *P < 0.05 versus bacterial CFUs detected in the control group. In three out of six mice in the control group, no V. cholerae cells were recovered in the small intestine or cecum (red arrows). b The competitive index represents the ratio of ΔtcpA mutant to N16961 recovered after infection either in the small intestine or cecum in each mouse after infection. *P < 0.05 versus the competitive index obtained from infection with no CL treatment