Molecular mechanism of biovar conversion of Yersinia pestis and the proposition of a new biovar:Microtus / 解放军医学杂志

ABSTRACT

Objective To study the genetic basis for biovar conversion of Y. pestis. Methods In silico comparative genomic analysis was conducted and some critical genetic variations of Yersinia pestis were comparatively analyzed by means of PCR and DNA sequencing. Results A 93bp in-frame deletion in glpD gene results in the glycerol negative characteristic of Orientalis strains. A point mutation in the napA gene may cause the negative characteristic of nitrate reduction in Mediaevalis and Microus strains. A 122-bp frameshift deletion in the araC gene may lead to the arabinose negative phenotype of Microus strains. Conclusion In this study, Microtus strains with their unique pathogenic, biochemical and molecular features, were proposed as a novel biovar Microtus. In the light of its differential ability to ferment glycerol and arabinose and to reduce nitrate, Y. pestis can be classified into four biovars-Antiqua(glycerol positive, arabinose positive and nitrate positive), Mediaevalis(glycerol positive, arabinose positive and nitrate negative), Orientalis(glycerol negative, arabinose positive and nitrate positive), and Microtus(glycerol positive, arabinose negative and nitrate negative).