Figure 1. GAS chronically colonizes the female genital tract.

Mice were infected with M28 GAS MEW123 or M1 GAS 5448, or GBS 874391 in the vaginal vault and colonization was monitored using colony counts. M28 MEW123 was inoculated in mice treated with estradiol at the onset of the experiment only (Initial [E2]), whereas mice inoculated with M1 GAS 5448 or GBS 874391 received weekly estradiol treatments to maintain estrous phase (Weekly [E2]). Total bacterial numbers and Gram-positive bacteria were also enumerated in colonized animals and showed no significant changes following challenge with GAS or GBS (Supplementary Fig. S1a,b, data not shown). Data are mean ± SEM of 12 mice and represents at least two independent experiments. Statistical comparisons are area under the curve, followed by Mann-Whitney U-test, with significance set at p < 0.05.