Distribution of Tryptophan-Dependent <I>Yersinia pestis</I> Variants in the Altai Mountain Natural Plague Focus
Carried out is the analysis of spatial location of tryptophan-dependent variants of plague microbe in the territory of Altai mountain plague natural focus. 1166 Y. pestis strains isolated in 1990–2010, were studied as regards nutrient requirements. 140 of them (12 %) were determined as tryptophan-dependent. The highest occurence of such strains was registered in Ulandryk focal region (21.6 % in average). Among strains isolated in Tarkhatin focal region only 2.3 % were tryptophan-dependent, and in Kuray region they were absent. Thus, the data obtained suggest that spatial heterogeneity of Y. pestis subsp. altaica in the focus takes place.