Comparative investigation of the role of the YadA, InvA, and PsaA genes in the pathogenicity of Yersinia pseudotuberculosis

The role of yadA, invA, and psaA genes in virulence was studied using a Yersinia pseudotuberculosis strain isolated from a patient with Far-East scarlatinoid fever as a model. Isogenic single, double, and multiple mutants of the studied genes were constructed, in which wild-type alleles were inactivated by the insertion of various antibiotic-resistance genes. LD50 and body weight dynamics of infected laboratory animals were used as virulence indicators. It has been established that the yadA gene is the primary determinant of bacterial virulence. This gene also causes the loss of body weight in laboratory animals infected by sublethal doses of Y. pseudotuberculosis. The invA gene, rather than yadA or psaA, plays a major role in the penetration of pathogenic microorganisms into eukaryotic cells. The effects of the yadA and invA genes on bacterial virulence and invasion, respectively, do not depend on the expression of other studied genes.