[Determination of genetic bases of auxotrophy in Yersinia pestis ssp. caucasica strains].

Based on the results of computer analysis of nucleotide sequences in strains Yersinia pestis and Y. pseudotuberculosis recorded in the files of NCBI GenBank database, differences between genes argA, aroG, aroF, thiH, and thiG of strain Pestoides F (subspecies caucasica) were found, compared to other strains of plaque agent and pseudotuberculosis microbe. Using PCR with calculated primers and the method of sequence analysis, the structure of variable regions of these genes was studied in 96 natural Y. pestis and Y. pseudotuberculosis strains. It was shown that all examined strains of subspecies caucasica, unlike strains of plague-causing agent of other subspecies and pseudotubercolosis microbe, had identical mutations in genes argA (integration of the insertion sequence IS100), aroG (insertion of ten nucleotides), aroF (inserion of IS100), thiH (insertion of nucleotide T), and thiG (deletion of 13 nucleotides). These mutations are the reason for the absence in strains belonging to this subspecies of the ability to synthesize arginine, phenylalanine, tyrosine, and vitamin B1 (thiamine), and cause their auxotrophy for these growth factors.