Genetic relationships between clinical and non-clinical strains of Yersinia enterocolitica biovar 1A as revealed by multilocus enzyme electrophoresis and multilocus restriction typing

Sarita Mallik,Jugsharan S Virdi

doi:10.1186/1471-2180-10-158

Abstract

BackgroundGenetic relationships among 81 strains of Y. enterocolitica biovar 1A isolated from clinical and non-clinical sources were discerned by multilocus enzyme electrophoresis (MLEE) and multilocus restriction typing (MLRT) using six loci each. Such studies may reveal associations between the genotypes of the strains and their sources of isolation.ResultsAll loci were polymorphic and generated 62 electrophoretic types (ETs) and 12 restriction types (RTs). The mean genetic diversity (H) of the strains by MLEE and MLRT was 0.566 and 0.441 respectively. MLEE (DI = 0.98) was more discriminatory and clustered Y. enterocolitica biovar 1A strains into four groups, while MLRT (DI = 0.77) identified two distinct groups. BURST (Based Upon Related Sequence Types) analysis of the MLRT data suggested aquatic serotype O:6,30-6,31 isolates to be the ancestral strains from which, clinical O:6,30-6,31 strains might have originated by host adaptation and genetic change.ConclusionMLEE revealed greater genetic diversity among strains of Y. enterocolitica biovar 1A and clustered strains in four groups, while MLRT grouped the strains into two groups. BURST analysis of MLRT data nevertheless provided newer insights into the probable evolution of clinical strains from aquatic strains.

Highlights

Genetic relationships among 81 strains of Y. enterocolitica biovar 1A isolated from clinical and non-clinical sources were discerned by multilocus enzyme electrophoresis (MLEE) and multilocus restriction typing (MLRT) using six loci each
Bacterial strains Eighty one strains of Y. enterocolitica biovar 1A were examined in this study
Electrophoretic types (ETs) and genetic diversity Activities of six enzymes were detected in all 81 strains of Y. enterocolitica biovar 1A and the reference strain Y. enterocolitica 8081

Summary

Introduction

Genetic relationships among 81 strains of Y. enterocolitica biovar 1A isolated from clinical and non-clinical sources were discerned by multilocus enzyme electrophoresis (MLEE) and multilocus restriction typing (MLRT) using six loci each. Such studies may reveal associations between the genotypes of the strains and their sources of isolation. The biovar 1A strains are thought to be non-pathogenic as they lack pYV (plasmid for Yersinia virulence) plasmid and major chromosomal virulence determinants [1]. A serotype O:6,30 (biovar 1A) strain was reported to cause placentitis and abortion in pregnant ewes [10]. Several recent studies suggest that these strains might possess novel, as yet unidentified, virulence determinants [12,13,14,15,16]

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