Application of PCR for identification of pathogenic plasmid markers of Yersinia enterocolitica strains isolated from humans and pigs

One hundred twenty-two strains of Yersinia enterocolitica, isolated from th e faeces of humans who showed symptoms typical of intestinal yersiniosis an d from pigs, were the subject of the study. The 0:3, 0:9, 0:2, 0:5 serogrou ps appeared in the tested population of Yersinia enterocolitica. Tested str ains were incubated on CRMOX agar and two groups were distinguished: calciu m dependent and Congo-red binding strains (CRMOX+phenotype) and strains whi ch don't show these properties (CRMOX- phenotype). A multiplex polymerase c hain reaction (PCR) was used to detect the presence of pathogenic plasmid m arkers, such as yadA and virF genes of tested Yersinia enterocolitica strai ns. The amplified fragment sizes were: 747 base-pairs (bp) for the vanAgene and 590 bp for the virF gene, which were obtained in PCR products of templ ate DNA from 36 Versinia enterocolitica strains. Among tested Yersinia ente rocolitica strains: 14 strains belong to 0:3 serogroup isolated from humans in 1998; 9 strains belong to 0:3 serogroup isolated from humans in 1996; 1 2 strains belong to O:3 serogroup and 1strain belongs to O:9 serogroup, whi ch were isolated from pigs in 1994-95. Moreover the presence of 590 bp ampl ified products, corresponding to virF gene fragment, was detected in PCR pr oducts of one Yersinia pseudotuberculosis. strain from pigs. Yad A and virF gene fragments were not detected in PCR products of template DNA from remaining Yersinia enterocolitica, Yersinia pseudotuberculosis, Y ersinia kristensenii strains. The presence of PCR products, corresponding to yadA and virF gene fragments , was detected only in amplified products of template DNA of CRMOX+ phenoty pe strains. A multiplex polymerase chain reaction,yadA-1, -2, virF-1, -2 pr imers is useful to detect pathogenic Versinia enterocolitica strains, when one directly isolated from research material.