Background: The aim of the study is to evaluate the diagnostic sensitivity of a 16S ribosomal RNA-based PCR on clinical specimens from patients with erythema migrans (EM) and neuroborreliosis and to compare the sensitivities with those obtained by in vitro culture and serological testing. A semiquantitative detection system, representing the input amount of specific DNA and thus the density of spirochetes in clinical specimens, indicated the preferred clinical sample to obtain for PCR testing.
Methods and results: Skin biopsy and urine samples from 31 patients with EM and cerebrospinal fluid (CSF) and urine samples from 30 patients with neuroborreliosis were investigated. Borrelia burgdorferi DNA was detected in 71% of the skin biopsy specimens and 13% of the urine samples from patients with EM. Forty-one percent of the patients with EM were found to have B burgdorferi-specific antibodies in serum, and B burgdorferi was cultured in 29% of the EM specimens. For patients with neuroborreliosis, the diagnostic sensitivities in CSF and urine samples were 17% and 7%, respectively. Specific intrathecal antibody production was found in 90% of the patients, and 87% showed elevated B burgdorferi antibodies in serum. In general, PCR of skin biopsy samples yielded very high amounts of amplicons versus low amounts for CSF and urine samples.
Conclusions: PCR of skin biopsy specimens is currently the most sensitive and specific test for the diagnosis of patients with EM, superior to culture and serological testing. For B burgdorferi-specific CSF disgnosis in patients with neuroborreliosis, the measurement of specific intrathecal antibody synthesis is superior to PCR. However, in patients with a short duration of disease (<14 days), PCR may be a useful diagnostic supplement. PCR of urine samples cannot be recommended at the present time for routine diagnosis of patients with EM or neuroborreliosis.