A genus of gram-negative bacteria characteristically appearing in chains of several segmenting organisms. It occurs in man and arthropod vectors and is found only in the Andes region of South America. This genus is the etiologic agent of human bartonellosis. The genus Rochalimaea, once considered a separate genus, has recently been combined with the genus Bartonella as a result of high levels of relatedness in 16S rRNA sequence data and DNA hybridization data.
