Murine gastrointestinal tract colonization by different E. faecalis strains following mixed inoculation. Percentages of CFU of E. faecalis strains from the initial inoculum mix and from stool samples collected 4 h and 1, 2, and 3 days after mixed inoculation of E. faecalis OG1RF::gfp (SD234) with the ΔeutBC strain (EFKK4) (A), OG1RF::gfp with the eutB mutant (eutBL3*) (EFKK12) (B), the ΔeutVW::gfp mutant (EFKK1) with the ΔeutBC mutant (C), and the ΔeutVW::gfp mutant with the eutB mutant (eutBL3*) (D). More than 100 CFU were scored for GFP fluorescence per mouse per time point. P values were calculated using an unpaired t test with Welch’s correction for the percentages of bacteria recovered from the fecal samples versus the amounts in the initial mixed inoculum.