KLK4 and infection: All mutants tested in coinfections with the glmS-pstS::Kanr WT strain were maintained at rates equal to that of the glmS-pstS::Kanr WT, as reflected by constant occurrence of the glmS-pstS::Kanr strain population at a mean of ∼50% of the total population of coinfecting Y. pestis immediately after infection (T0) and at 7 days (T7) postinfection (Fig. 2).