IDENTIFICATION OF 3 SPECIES OF BORRELIA-BURGDORFERI SENSU-LATO (BORRELIA-BURGDORFERI SENSU-STRICTO, B-GARINII, AND B. AFZELII) AMONG ISOLATES FROM ACRODERMATITIS CHRONICA ATROPHICANS LESIONS

In Europe, at least three species of Borrelia are known to be causativ e agents of lyme borreliosis: B. burgdorferi sensu stricto, B. garinii , and B. afzelii. Observable differences in the molecular characterist ics of the three species have led to speculation that they may also di ffer in their pathogenic potential and/or tissue tropisms. Several stu dies have found an association between the chronic skin manifestation of Lyme borreliosis, acrodermatitis chronica atrophicans, and infectio n by B. afzelii. We sought to find further evidence for such a correla tion by studying the genetic profiles of 22 strains of B. burgdorferi sensu lato derived from 21 patients who presented to the University Me dical Center, Ljubljana, Slovenia between 1992 and 1995. Strains were isolated in culture from skin biopsies of acrodermatitis chronica atro phicans lesions; in the case of one patient two separate acrodermatiti s chronica atrophicans lesions were cultured. All 21 patients had clin ically typical lesions with ''classic'' histopathology and high IgG an tibody titers to B. burgdorferi sensu lato. Strains were characterized and typed by 16S ribosomal RNA-specific polymerase chain reaction and determination of their large restriction fragment patterns using puls ed-field gel electrophoresis of MluI-digested genomic DNA. Of the 22 i solates studied, 17 possessed the highly conserved MLa1 pattern charac teristic of B. afzelii. The remaining five isolates possessed large re striction fragment patterns that were typical of B. garinii (MLg2, fou r isolates from three patients) and B. burgdorferi sensu stricto (MLb2 , one isolate). The results of 16S ribosomal RNA-specific polymerase c hain reaction were concordant with these species designations. These d ata show that B. afzelii is the predominant, but not the exclusive, et iologic agent of acrodermatitis chronica atrophicans.