Molecular typing of Borrelia burgdorferi sensu lato: Taxonomic, epidemiological, and clinical implications

Borrelia burgdorferi sensu lato, the spirochete that causes human Lyme borr eliosis (LB), is a genetically and phenotypically divergent species. In the past several years, various molecular approaches have been developed and u sed to determine the phenotypic and genetic heterogeneity within the LB-rel ated spirochetes and their potential association with distinct clinical syn dromes. These methods include serotyping, multilocus enzyme electrophoresis , DNA-DNA reassociation analysis, rRNA gene restriction analysis (ribotypin g), pulsed-field gel electrophoresis, plasmid fingerprinting, randomly ampl ified polymorphic DNA fingerprinting analysis, species-specific PCR and PCR -based restriction fragment length polymorphism (RFLP) analysis, and sequen ce analysis of 16S rRNA and other conserved genes. On the basis of DNA-DNA reassociation analysis, 10 different Borrelia species have been described w ithin the B. burgdorferi sensu lato complex: B. burgdorferi sensu stricto, Borrelia garinii, Borrelia afzelii, Borrelia japonica, Borrelia andersonii, Borrelia valaisiana, Borrelia lusitaniae, Borrelia tanukii, Borrelia turdi , and Borrelia bissettii sp. nov. To date, only B. burgdorferi sensu strict o, B. garinii, and B. afzelii are well known to be responsible for causing human disease. Different Borrelia species have been associated with distinc t clinical manifestations of LB. In addition, Borrelia species are differen tially distributed worldwide and may be maintained through different transm ission cycles in nature. In this paper, the molecular methods used for typi ng of B. burgdorferi sensu lato are reviewed. The current taxonomic status of B. burgdorferi sensu lato and its epidemiological and clinical implicati ons, especially correlation between the variable clinical presentations and the infecting Borrelia species, are discussed in detail.