Bartonella spp. infection in rodents from different habitats in the Mazury Lake District, Northeast Poland.

Four rodent species (Clethrionomys glareolus, Apodemus flavicollis, Microtus arvalis, M. oeconomus) were captured in the period 2004-2006 in the Mazury Lake District, Northeast Poland, to determine the prevalence and genetic diversity of Bartonella species. The presence of bartonellae was assessed using polymerase chain reaction (PCR) with primers CS140f and BhCS1137n, amplifying a fragment of the gltA gene. Bartonella DNA was detected in 313 (30.6%) of 1024 rodents sampled: in 181 C. glareolus, 68 A. flavicollis, 50 M. arvalis, and 14 M. oeconomus, representing prevalence of 31.0%, 42.2%, 32.9%, and 11.1%, respectively. Comparison of the Bartonella gltA gene sequences from 38 isolates revealed six phylogenetic subgroups, out of 15 unique gltA sequences, and therein from one to five genotypic variants with homology of 88.6-99.1%. Six of 13 (46.2%) isolates from C. glareolus were identical to B. grahamii, species associated with human illness. These results have important public health implication, notably in relation to the risk of infection in humans following exposure to rodent bartonellae.