[Trimethoprim resistance--a differential trait of strains of Yersinia pestis from a variety of voles].

Strains of all Y. pestis varieties except for those isolated from voles are highly sensitive to trimethoprim when grown on cultivation media, even when thymidine is added to the medium. The ability to grow on thymidine-containing rich media after trimethoprim addition is a property differentiating Y. pestis variety isolated from voles from the other varieties. These data were confirmed by testing 360 Y. pestis strains obtained from collections of several antiplague institutes and stations of the USSR.