Electrotransformation of the Spirochete Borrelia burgdorferi

Borrelia burgdorferi is an etiologic agent of Lyme disease, the most common arthropod-borne disease in the United States (1 ,2 ). The bacterium, a member of the spirochete phylum, has a genome predominantly composed of linear DNA molecules (3 ,4 ). Formulating a medium in which B. burgdorferi grows in vitro was the first step toward a genetic understanding of the physiology and pathogenesis of the organism (5 ,6 ). The growth of B. burgdorferi as single colonies in solid medium (7 –9 ) has facilitated mutant isolation by selection (10 ,11 ), although a defined medium for selection of auxotrophs is not currently available. The transformation system described in this chapter will be useful for manipulating the spirochete on a molecular genetic level.