COSEGREGATION OF A NOVEL BARTONELLA SPECIES WITH BORRELIA-BURGDORFERIAND BABESIA-MICROTI IN PEROMYSCUS-LEUCOPUS

During surveillance for various tickborne pathogens in the upper Midwe st during the summer and early fall of 1995, a Bartonella-like agent w as detected in the blood of mice that were concurrently infected with Borrelia burgdorferi or Babesia microti (or both). The organism was is olated in pure culture after inoculation of blood from wild-caught mic e into C.B-17 scid/scid mice. Phylogenetic analysis of the 16S rRNA an d the citrate synthase genes showed that the novel Bartonella species and a Bartonella isolate from a mouse captured on Martha's Vineyard, M assachusetts, were closely related to each other and secondarily relat ed to Bartonella grahamii and Bartonella vinsonii. Further analysis of Peromyscus leucopus blood and tissue samples demonstrated that the no vel Bartonella species was exclusively found in conjunction with B. bu rgdorferi and B. microti. Patent coinfection with these agents may be relatively frequent in naturally infected mice.