Molecular characterization and proposal of a neotype strain for Bartonella bacilliformis.

Bartonella bacilliformis, the etiologic agent of bartonellosis, was characterized biochemically and by DNA hybridization, guanine-plus-cytosine content, genome size, and 16S rRNA sequencing. DNAs from the two strains in our collection exhibited 97% relatedness in hydroxyapatite reactions done at 55 degrees C (optimal reassociation criterion) and 100% relatedness in reactions done at 70 degrees C (stringent reassociation criterion). There was no evidence of divergence within the related sequences. B. bacilliformis DNA showed no relatedness to the cat scratch disease bacillus or to a strain of a second species in the same genus as the cat scratch disease bacillus in hybridization reactions done at 65 degrees C. The guanine-plus-cytosine contents of DNAs from the two B. bacilliformis strains were 39 and 40 mol%. Time course reassociation, done by determining spectrophotometrically the time required for one-half of the denatured DNA to form duplexes, indicated that B. bacilliformis has a genome size of approximately 4 x 10(8). The 16S rRNA sequence analysis indicated that B. bacilliformis is in the alpha-2 subgroup of the purple bacteria, class Proteobacteria, and that its closest relatives are Rochalimaea quintana and Brucella abortus. Strain KC583 (= Herrer 020/F12,63 = ATCC 35685) is proposed as the type strain of B. bacilliformis.