Impact of Activation and Subsequent Antimicrobial Treatment of Dormant Endometrial Streptococci in the Thoroughbred Problem Mare - A Descriptive Field Study

The expected fertility of problem mares (non-pregnant for > 3 cycles despite intensive breeding management) is reduced compared to the general broodmare population (15 to 50% vs. 80 to 85% foaling rate). Streptococcus equi subspecies zooepidemicus (S. zoo) can enter an inactive/dormant state with a multifocal distribution deep within the endometrium of a chronically infected mare. As most antimicrobial compounds assert their activity against metabolically active bacterial cells, we hypothesized that activation of bacterial growth and subsequent antimicrobial treatment of dormant streptococci would increase treatment efficacy and indirectly increase the fertility of the problem mare. [...]