FIG 7.

Ability of C. muridarum with or without mutations in tc0668 and/or tc0237 to colonize the mouse GI tract following intragastric inoculation. Wild-type (G13.32.1, n = 5, panels a and b) or mutant (G40.50.2, n = 5, panels c and d; G13.11.1, n = 5, panels e and f; G28.51.1, n = 5, panels g and j) C. muridarum organisms were inoculated intragastrically into female C57BL/6J mice at 2 × 10⁵ IFUs (panels a to h) or 1 × 10⁷ IFUs (panels i and j) per mouse. At various time points postinoculation, as indicated on the x axis, rectal (left panels) and vaginal (right panels) swabs were taken for titration of live C. muridarum organisms. The recovery of live organisms is expressed as log₁₀ IFUs per swab, as displayed on the y axis. Note that C. muridarum organisms with single mutations in either tc0237 (G40.50.2) or tc0668 (G13.11.1) developed significantly delayed/reduced courses of shedding from the mouse GI tract at an inoculation dose of 1 × 10⁵ IFUs per mouse (panels c or e; *, P < 0.05, area under the curve or individual time points, Wilcoxon rank sum test), while the double mutant (G28.51.1) failed to shed any detectable live organisms even at an inoculation dose of 1 × 10⁷ IFUs per mouse (panel I; P < 0.01, area under the curve, Wilcoxon rank sum test). No significant live organisms were detected in any of the vaginal swabs.