FATE OF BORRELIA-BURGDORFERI DNA IN TISSUES OF INFECTED MICE AFTER ANTIBIOTIC-TREATMENT

Persistence of Borrelia burgdorferi DNA in tissues following antibioti c treatment was evaluated in C3H mice inoculated intradermally with 10 (3) B. burgdorferi N40 or sterile medium. Half of the infected mice an d all of the uninfected mice were treated with ceftriaxone 15 days aft er inoculation for 5 days. Ear and urinary bladder samples were collec ted on days 20, 30, and 60 after inoculation for culture and for extra ction of DNA and amplification of specific spirochetal DNA by polymera se chain reaction (PCR). PCR primers were specific for a 280-bp portio n of a highly conserved region of the gene encoding outer surface prot ein (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 (35/3 6 mice) and bladders (33/36). Both tissues became uniformly negative a t the earliest interval tested after antibiotic treatment. Thus, the a bility to amplify B. burgdorferi DNA quickly disappeared from tissues that had become culture-negative after antibiotic treatment, suggestin g that serial study of PCR-positive tissues and fluids may be useful f or evaluating the efficacy of antibiotic therapy in human Lyme disease .