PCR Detection of Virulence Genes in <i>Yersinia enterocolitica</i> and <i>Yersinia pseudotuberculosis</i> and Investigation of Virulence Gene Distribution

<jats:title>ABSTRACT</jats:title> <jats:p> PCR-based assays were developed for the detection of plasmid- and chromosome-borne virulence genes in <jats:italic>Yersinia enterocolitica</jats:italic> and <jats:italic>Yersinia pseudotuberculosis</jats:italic> , to investigate the distribution of these genes in isolates from various sources. The results of PCR genotyping, based on 5 virulence-associated genes of 140 strains of <jats:italic>Y. enterocolitica</jats:italic> , were compared to phenotypic tests, such as biotyping and serotyping, and to virulence plasmid-associated properties such as calcium-dependent growth at 37°C and Congo red uptake. The specificity of the PCR results was validated by hybridization. Genotyping data correlated well with biotype data, and most biotypes resulted in (nearly) homogeneous genotypes for the chromosomal virulence genes ( <jats:italic>ystA</jats:italic> , <jats:italic>ystB</jats:italic> , and <jats:italic>ail</jats:italic> ); however, plasmid-borne genes ( <jats:italic>yadA</jats:italic> and <jats:italic>virF</jats:italic> ) were detected with variable efficiency, due to heterogeneity within the bacterial population for the presence of the virulence plasmid. Of the virulence genes, only <jats:italic>ystB</jats:italic> was present in biotype 1A; however, within this biotype, pathogenic and apathogenic isolates could not be distinguished based on the detection of virulence genes. Forty <jats:italic>Y. pseudotuberculosis</jats:italic> isolates were tested by PCR for the presence of <jats:italic>inv</jats:italic> , <jats:italic>yadA</jats:italic> , and <jats:italic>lcrF</jats:italic> . All isolates were <jats:italic>inv</jats:italic> positive, and 88% of the isolates contained the virulence plasmid genes <jats:italic>yadA</jats:italic> and <jats:italic>lcrF</jats:italic> . In conclusion, this study shows that genotyping of <jats:italic>Yersinia</jats:italic> spp., based on both chromosome- and plasmid-borne virulence genes, is feasible and informative and can provide a rapid and reliable genotypic characterization of field isolates. </jats:p>