Phenotypic and genotypic presence of the Yersinia virulence plasmid do not affect the production of enterotoxin YstA by Yersinia enterocolitica strains.

The aim of the study was to determine whether the presence of the Yersinia virulence plasmid could affect the production of enterotoxin YstA by Y. enterocolitica strains isolated from pigs which are the main source of infection for humans. The phenotypic features characteristic for the Yersinia virulence plasmid were detected on CRMOX agar in 8 out of 12 strains producing enterotoxin YstA, in 5 out of 12 doubtful strains, and in 11 out of 12 strains not producing YstA.