Molecular detection and genetic identification of Borrelia garinii and Borrelia afzelii from patients presenting with a rare skin manifestation of prurigo pigmentosa in Taiwan.

Objectives: To determine the genetic identity of Borrelia spirochetes isolated from patients with an unusual skin lesion of prurigo pigmentosa (PP) in Taiwan. The causative agents responsible for human borreliosis were clarified.

Methods: Serum samples and skin specimens were collected from 14 patients with suspected PP and five controls. Serological testing by Western immunoblot analysis and isolation of Borrelia spirochetes from skin specimens were used to verify the Borrelia infection. Genetic identities of isolated spirochetes were determined by analyzing the gene sequences amplified by PCR assay based on the 5S (rrf)-23S (rrl) intergenic spacer amplicon gene of Borrelia burgdorferi sensu lato.

Results: Borrelia spirochetes were isolated from skin biopsies of three patients. Serological evidence of Borrelia infection in these patients was also confirmed by elevated IgG and IgM antibodies against the major protein antigens of B. burgdorferi. Phylogenetic analysis revealed that these detected spirochetes are genetically affiliated to the genospecies of Borrelia garinii and Borrelia afzelii with high sequence homology within the genospecies of B. garinii (91.0-98.7%) and B. afzelii (97%).

Conclusions: This study provides the first evidence of B. garinii and B. afzelii isolated and identified in patients with PP. Whether this unusual skin lesion is a new manifestation of Lyme disease needs to be studied further.