Fate of Borrelia burgdorferi DNA in tissues of infected mice after antibiotic treatment.

 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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