Diversity of bartonellae associated with small mammals inhabiting Free State province, South Africa

The prevalence and diversity of bartonellae infecting the blood of 10 small mammal species inhabiting nine Nature Reserves of the Free State province, South Africa, was assessed using phenotypic, genotypic and phylogenetic methods. Of 86 small mammals sampled, 38 animals belonging to five different species yielded putative bartonellae. Thirty-two isolates were confirmed as bartonellae and were characterized by comparison of partial citrate synthase gene (gltA) sequences. Phylogenetic reconstructions derived from alignment of these sequences with those available for other bartonellae indicated that the South African rodent-associated isolates formed two distinct clades within the radius of the genus Bartonella. One of these clades also included recognized Bartonella species associated with rodents native to Eurasia but not to the New World, whereas the second clade contained exclusively isolates associated with South African rodents. Comparison of gltA sequences delineated the isolates into a number of ecologically distinct populations and provided an indication that a combination of phylogenetics and the identification of sequence clusters in housekeeping protein-encoding genes could be developed as a key criterion in the classification of bartonellae. This study is the first to investigate wildlife-associated bartonellae in Africa, adding support to their ubiquity and broad diversity and to the paradigm that the phylogenetic positions of the Bartonella species encountered today have been influenced by the geographical distribution of their hosts.