Abstract
Lyme disease is a tick-borne infection caused by the bacteria Borrelia burgdorferi Current diagnosis of early Lyme disease relies heavily on clinical criteria, including the presence of an erythema migrans rash. The sensitivity of current gold-standard diagnostic tests relies upon antibody formation, which is typically delayed and thus of limited utility in early infection. We conducted a study of blood and skin biopsy specimens from 57 patients with a clinical diagnosis of erythema migrans. Samples collected at the time of diagnosis were analyzed using an ultrasensitive, PCR-based assay employing an isothermal amplification step and multiple primers. In 75.4% of patients, we directly detected one or more B. burgdorferi genotypes in the skin. Two-tier testing showed that 20 (46.5%) of those found to be PCR positive remained serologically negative at both acute and convalescent time points. Multiple genotypes were found in three (8%) of those where a specific genotype could be identified. The 13 participants who lacked PCR and serologic evidence for exposure to B. burgdorferi could be differentiated as a group from PCR-positive participants by their levels of several immune markers as well as by clinical descriptors such as the number of acute symptoms and the pattern of their erythema migrans rash. These results suggest that within a Mid-Atlantic cohort, patient subgroups can be identified using PCR-based direct detection approaches. This may be particularly useful in future research such as vaccine trials and public health surveillance of tick-borne disease patterns.