Genetic transformation of the Lyme disease agent Borrelia burgdorferi with coumarin-resistant gyrB

No useful method to genetically manipulate Borrelia burgdorferi, the causative agent of Lyme disease, has been developed previously. We have used resistance to the coumarin antibiotic coumermycin Al, an inhibitor of DNA gyrase, as a genetic marker to monitor the transformation of B. burgdorferi by electroporation. Introduction of site-directed mutations into the gyrB gene demonstrated that transformation was successful, provided evidence that homologous recombination occurs on the chromosome, and established that mutations at Arg-133 ofDNA gyrase B confer coumermycin Al resistance in B. burgdorferi. The coumermycin Al-resistant gyrB marker and genetic transformation can now be applied toward dissecting the physiology and pathogenesis of the Lyme disease agent on a molecular genetic level