J Infect Dis. 1994 Nov;170,5:1312-6 Comment in: J Infect Dis. 1995 May;171,5:1379-80. Fate of Borrelia burgdorferi DNA in tissues of infected mice after antibiotic treatment. Malawista SE, Barthold SW, Persing DH. Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut. Persistence of Borrelia burgdorferi DNA in tissues following antibiotic treatment was evaluated in C3H mice inoculated intradermally with 10,3, B. burgdorferi N40 or sterile medium. Half of the infected mice and all of the uninfected mice were treated with ceftriaxone 15 days after 38inoculation for 5 days. Ear and urinary bladder samples were collected on days 20, 30, and 60 after inoculation for culture and for extraction of DNA and amplification of specific spirochetal DNA by polymerase chain reaction, PCR. PCR primers were specific for a 280-bp portion of a highly conserved region of the gene encoding outer surface protein, Osp, A of B. burgdorferi and for a 328-bp part of the OspB gene. There was excellent concordance between culture and PCR for ears, 35/36 mice, and bladders, 33/36. Both tissues became uniformly negative at the earliest interval tested after antibiotic treatment. Thus, the ability to amplify B. burgdorferi DNA quickly disappeared from tissues that had become culture-negative after antibiotic treatment, suggesting that serial study of PCR-positive tissues and fluids may be useful for evaluating the efficacy of antibiotic therapy in human Lyme disease. 2 out of 5 mice tested 60 days after treatment were found to be positive on culture; 1 of these mice was also positive by PCR. The authors speculate that this could be due to:, a, reinfection, which they consider .highly unlikely.,, b, contamination, or, c, the .resurgence of spirochetes in animals not completely sterilized by antibiotics. This last possibility will bear further scrutiny because late recurrences of Lyme disease without obvious reinfection may occur in humans.[Diagnosis:] Positive PCR results were found to suggest active infection. .Unless some patients with Lyme disease have a defect in their ability to degrade spirochetal DNA, these results suggest that persisting PCR positivity indicates persisting infection
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