Genetic Analysis of the Flagellin Gene of Lyme Disease Spirochetes (Borrelia burgdorferi) Isolated from Rodents in Taiwan

Department of Parasitology and Tropical Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China
J Med Sci 10/2009; 29(5):249-255.


Background: The fl agellin gene of Borrelia burgdorferi is highly conserved, and genomic analysis among Borrelia iso-lates using sequence similarity of a fl agellin gene has been proven useful for the species identifi cation and genomic typing of Borrelia spirochetes isolated from various biological and geographical sources. Thus, we analyzed the fl agellin gene of Lyme disease spirochetes for the fi rst time in Taiwan. Methods: The genetic identities of Taiwan isolates (TWKM1-7) were determined by comparing their sequence similarities of the PCR-amplifi ed fl agellin genes with three major genospe-cies of Lyme disease spirochetes. Their phylogenetic relationships were also analyzed by neighbour-joining and maxi-mum parsimony methods. Results: The sequence similarity of Taiwan isolates revealed a highly homogeneous genotype, ranging from 97.8% to 100%, within the genospecies of B. burgdorferi sensu stricto and was clearly distinguished from other genospecies of Lyme disease spirochetes with a high sequence variability (>4.9%) of the fl agellin gene. In addition, phylogenetic analysis based on the fl agellin gene also revealed a highly genetic divergence between Taiwan isolates and other Borrelia strains that were isolated from different biological and geographical sources. Conclusions: Our results provide the fi rst investigation on the genetic identity of the fl agellin gene of these Taiwan isolates and confi rm that these Taiwan isolates are genetically related to the genospecies of B. burgdorferi sensu stricto.

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