Figure 5.

Region of difference 2 (RD2) promotes the ability of serotype M28 group A Streptococcus (GAS) isolates to colonize the murine vagina. Mice treated with estradiol (0.5 mg) were vaginally challenged with 1 × 10⁴ colony-forming units (CFUs) of the indicated GAS strains. Shown is the mean number (± the standard error of the mean) of CFUs recovered from vaginal swabs over time. A repeated-measure analysis indicated that a statistically significantly lower number of CFUs was recovered over time for the RD2 deletion mutant strain, relative to the parental and complemented mutant strains (P < .01).