A 2-YEAR PROSPECTIVE-STUDY TO COMPARE CULTURE AND POLYMERASE CHAIN-REACTION AMPLIFICATION FOR THE DETECTION AND DIAGNOSIS OF LYME BORRELIOSIS

Aim-To compare polymerase chain reaction (PCR) amplification of borrel ial DNA and culture isolation of spirochaetes for the diagnosis of lym e borreliosis by direct detection of Borrelia burgdorferi sensu late i n patients with erythema migrans and acrodermatitis chronica atrophica ns lesions. Methods-Skin biopsy specimens from erythema migrans and ac rodermatitis chronica atrophicans lesions were subdivided and tested b y PCR amplification assay and culture using two artificial growth medi a, Barbour-Stoenner-Kelly II (BSK II) and modified Kelly-Pettenkofer ( MKP). Five classes of lesions were studied: typical erythema migrans, spontaneously resolved erythema migrans, atypical/partially treated er ythema migrans, typical acrodermatitis chronica atrophicans, and atypi cal/partially treated acrodermatitis chronica atrophicans. Results-For both erythema migrans and acrodermatitis chronica atrophicans lesions , the most sensitive detection method was MKP culture. PCR was less se nsitive than MKP culture, but more sensitive than BSK II culture. Resu lts-For 758 typical erythema migrans specimens showed positivity rates of 36% for MKP, 25% for PCR, and 24% for BSK II. Differences were sta tistically significant. The overall positivity rate for all three meth ods combined was 54%, but few specimens (6%) were positive by all thre e methods. Examination of multiple erythema migrans lesions from the s ame patient increased the diagnostic yield. These findings, and simila r results for acrodermatitis chronica atrophicans lesions, suggest tha t the distribution of spirochaetes in skin biopsies is not homogeneous . Conclusions-Although possessing the potential to provide a rapid dia gnosis, PCR is not more sensitive than culture for the direct detectio n of borrelia. Spirochaetes appear to be unevenly distributed througho ut biopsy specimens, suggesting that diagnosis of Lyme borreliosis by direct detection of the causative agent in skin lesions is vulnerable to sample bias.