An OspA-based genospecies identification of Lyme disease spirochetes (Borrelia burgdorferi) isolated in Taiwan.

To further identify the genospecies of Lyme disease spirochetes (Borrelia burgdorferi) isolated in Taiwan, we analyzed the genomic identities of these Taiwan isolates (TWKM1-7) by genospecies-specific polymerase chain reaction (PCR) assay, restriction fragment length polymorphism (RFLP) analysis, and gene sequencing based on the OspA gene sequences of B. burgdorferi sensu lato. PCR analysis indicates that all of these Taiwan isolates were genetically related to the genospecies of B. burgdorferi sensu stricto by their differential reactivities with genospecies-specific PCR primers. After cleavage by DraI, three different RFLP patterns in relation to three different genospecies of Lyme disease spirochetes were observed, and all of these Taiwan isolates were affiliated with the genospecies of B. burgdorferi sensu stricto. The phylogenetic analysis also reveals that the sequence similarity of PCR-amplified OspA gene of these Taiwan isolates is highly homogeneous, with a homogeneity of more than 99.8% within the genospecies of B. burgdorferi sensu stricto. These results confirm that the genomic identities of these Taiwan isolates belong to the genospecies of B. burgdorferi sensu stricto.