Development of multiple-locus variable-number tandem-repeat analysis for Yersinia enterocolitica subsp. palearctica and its application to bioserogroup 4/O3 subtyping

Abstract

Yersinia enterocolitica bioserogroup 4/O3 is the predominant causative agent of yersiniosis in Europe and North America. Multiple-locus variable-number tandem-repeat analysis (MLVA) was developed to improve the resolution power of classical genotyping methods. MLVA based on six loci was able to distinguish 76 genotypes among 91 Y. enterocolitica isolates of worldwide origin and 41 genotypes among 51 nonepidemiologically linked bioserogroup 4/O3 isolates, proving that it has a high resolution power. However, only a slight correlation of the MLVA genotypes and the geographic distribution of the isolates was observed. Although MLVA was also capable of distinguishing strains of Y. enterocolitica subsp. palearctica O9 and O5,27, there was only a minor correlation between the MLVA genotypes and serogroups. MLVA may be a helpful tool for epidemiological investigations of Y. enterocolitica subsp. palearctica outbreaks.

FIG. 1.

DGE separation of the VNTR types for each of the seven MLVA markers investigated. The representative amplicons of each size group were amplified separately and mixed prior to electrophoresis. This mixture was loaded close to the 20-bp step ladder (lanes M). For V2A, an additional 50-bp step ladder was used (lane M50). The amplicon length of only the representative band of each size variant determined by DNA sequence analysis is marked. The real dimensions of the gel fragments shown were transformed proportionally to support the highest printout resolution.

FIG. 2.

Cluster analysis of 76 MLVA genotypes of Y. enterocolitica subsp. palearctica compared to their geographic origin and bioserogroup. The tree was generated by the average linkage (unweighted pair group method with arithmetic mean) agglomeration method. Abbreviations: G, genotype; ST, serogroup; BT, biotype; SAF, South Africa; NC, New Caledonia; NZ, New Zealand; GB, Great Britain; na, not available; nd, not determined.