Adaptation variability of Yersinia pseudotuberculosis during long-term persistence in soil.

Adaptation changes in the morphological and biological characteristics of pathogenic Yersinia pseudotuberculosis inhabiting a model soil ecosystem for a long time were studied. Changes in cultural, biochemical, and morphological characteristics of Yersinia and a decrease or loss of virulence were observed under these conditions. The detected changes were phenotypical, i. e. several passages in common nutrient media restored the original characteristics of the strain.