First isolation and molecular identification of Borrelia burgdorferi sensu stricto and Borrelia afzelii from skin biopsies of patients in Taiwan.

OBJECTIVES: In order to clarify the transmission cycle and genetic identity of Borrelia spirochetes in the non-endemic country of Taiwan, the causative agents responsible for human borreliosis were isolated from skin biopsies of patients and their genetic identities were determined.
METHODS: Serum samples and skin biopsy specimens were collected from 95 patients: 85 with suspected Lyme disease and 10 controls. Infection with Borrelia burgdorferi was verified by Western immunoblot analysis and isolation of the Borrelia spirochetes from skin biopsy specimens. The genetic identities of these isolated spirochetes were determined by analyzing the gene sequences amplified by polymerase chain reaction assay based on the 5S (rrf)-23S (rrl) intergenic spacer amplicon gene of B. burgdorferi sensu lato.
RESULTS: Serological evidence of B. burgdorferi infection was confirmed by elevated IgG and IgM antibodies against the major protein antigens of B. burgdorferi. Borrelia spirochetes were isolated from the skin biopsies of two patients. Phylogenetic analysis revealed that these detected spirochetes were genetically affiliated to the genospecies Borrelia burgdorferi sensu stricto and Borrelia afzelii, with a high sequence homology within the genospecies of B. burgdorferi sensu stricto (98.7-100%) and B. afzelii (100%), respectively.
CONCLUSIONS: This study provides convincing evidence of B. burgdorferi sensu stricto and B. afzelii isolated and identified for the first time in Taiwan, and highlights the significance of genetic diversity of Borrelia spirochetes among patients in Taiwan.