Recurrent Lyme disease usually caused by reinfection

A study in 17 adult patients with culture-confirmed episodes of erythema migrans-whose first bout of Lyme disease was treated appropriately with standard courses of antibiotics-found that additional consecutive episodes of erythema migrans were due to reinfection, not relapse.

In making this determination, investigators examined the genotype of the gene encoding outer-surface protein C (ospC) of Borrelia burgdorferi strains detected in cultures of skin or blood specimens from patients who had experienced several episodes of erythema migrans. (Paired consecutive occurrences in the 17 patients totaled 22 because although most of the participants had 2 episodes, a few patients had 3 or 4.)

None of the paired occurrences of erythema migrans from initial and subsequent consecutive episodes shared the same ospC genotype. Furthermore, using a separate genotyping method, investigators confirmed infection with a different genotype of B burgdorferi in all 22 of the paired episodes. In total, 12 different ospC genotypes caused infection (Nadelman RB, et al. N Engl J Med. 2012;367[20]:1883-1890).

Commentary

This study should offer reassurance to those who are concerned that a second bout of erythema migrans represents failure of a first round of treatment for Lyme disease. Rather than focusing on chronic, relapsing infection, our patients and their parents can be told to work on tick avoidance and early tick removal. -Michael Burke, MD