Lyme disease is increasing in both incidence and geographic distribution. Given that the etiologic agent, Borrelia burgdorferi, is difficult to culture in routine clinical laboratories, there has been a long-standing controversy over whether this pathogen can cause relapsing and/or chronic disease. Recurrent disease—often manifesting as recurrent erythema migrans, a hallmark of Lyme disease—is common and can follow appropriate antibiotic treatment. Proponents of “chronic Lyme disease,” which manifests primarily as neurocognitive symptoms and/or fatigue, suggest that it can occur whether or not the patient has received appropriate antimicrobial therapy during the initial infection; they argue that prolonged antibiotic therapy is needed in such cases.

In a prospective study, Nadelman and colleagues (2012) used three different genetic tests—multilocus sequence typing and analyses of ospC and the 16S–23S ribosomal RNA intergenic region—to characterize the B. burgdorferi genotype from 22 paired consecutive episodes of erythema migrans in 17 patients. Isolates were cultured from skin, blood, or both, and all patients received standard courses of antibiotics. None of the isolates from the 22 paired consecutive episodes was of the same genotype. One patient with four episodes of erythema migrans (i.e., three paired episodes) had the same genotype isolated from lesions during the first and third episodes. However, the lesions in these two episodes were anatomically and temporally distinct, occurring on the right ankle and the right buttock, respectively, and appearing 5 years apart. The third episode in this patient was associated with a punctum at the center of the lesion, which suggested a recent tick bite rather than relapsed infection. Moreover, the ospC genotype identified for the isolates from the first and third episodes was that most commonly identified. If each patient was infected with two different genotypes at the first episode of erythema migrans, the probability that chance alone accounted for these findings is 1 in 5 million; even if each patient was initially infected with five different genotypes, the probability that chance alone explains the detection of different genotypes is less than 0.01.

Perspective: This study demonstrates that patients with recurrent erythema migrans who received appropriate antibiotic therapy for their initial episode are reinfected with B. burgdorferi as opposed to having relapses of disease. These findings add to the mounting clinical evidence that the traditionally recommended courses of antibiotics are sufficient to eradicate B. burgdorferi and lend further support to guidelines endorsed by the Infectious Diseases Society of America, which posit that prolonged antibiotic therapy for Lyme disease is not helpful.