Rodents (Muridae, Cricetidae) represent an important group of mammalian hosts as considered reservoir host of Bartonella species. More than 20 Bartonella spp. are associated with rodents and several rodent-associated Bartonella species have been related to human diseases. The aim of the research was to investigate Bartonella spp. prevalence and genetic diversity in various species of rodents collected in Lithuania. A total of 580 rodents representing eighth species – A. flavicollis (n=201), A. agrarius (n=76), M. musculus (n=12), M. minutus (n=40), M. glareolus (n=165), M. oeconomus (n=58), M. agrestis (n=25) and M. arvalis (n=3) were captured with live or snap traps in 12 locations of Lithuania during 2015–2016. The presence of Bartonella DNA was examined by real-time PCR targeting the ssrA gene. The molecular characterization of the bacteria strains was based on sequence analysis of two housekeeping genes (rpoB, groEL) and the 16S–23S rRNA intergenic spacer region (ITS). The overall prevalence of Bartonella spp. was 54.8% and ranged from 8.3% in M. musculus, 15.8% in A. agrarius, 33.3% in M. arvalis, 42.4% in M. glareolus, 53.4% in M. oeconomus, 57.5% in M. minutus, 79.6% in A. flavicollis to 80% in M. agrestis. Phylogenetic analysis based on two housekeeping genes and ITS region demonstrated that rodents harbor multiple Bartonella species belonging to six clades associated with human pathogenic B. grahamii, B. rochalimae and B. tribocorum species, and other species B. taylorii, B. coopersplainsensis and B. doshiae which pathogenicity to humans is still unknown. Bartonella strains belonged to B. grahamii and B. taylorii clades were heterogenic. Phylogenetic analysis based on each of the targets demonstrated high variability of B. taylorii and B. grahamii strains between different and either same rodent species. [...]

Worldwide, Bartonella infections are known to inflict a wide range of mammals and, within rodents alone, more than 20 Bartonella species have been detected. There is, however, a lack of studies on the presence of Bartonella spp. in rodents in the Baltic region. We analysed 580 individuals belonging to eight small rodent species trapped in coastal and continental areas of Lithuania during 2015–2016. The presence of Bartonella DNA was examined by real-time PCR targeting the ssrA gene. The molecular characterization of the bacteria strains was based on sequence analysis of two housekeeping genes (rpoB, groEL) and the intergenic spacer region (ITS). For the rodents overall, the prevalence of Bartonella spp. was 54.8%, while the prevalence figures for each of the individual species were 8.3% in M. musculus, 15.8% in A. agrarius, 33.3% in M. arvalis, 42.4% in M. glareolus, 53.4% in M. oeconomus, 57.5% in M. minutus, 79.6% in A. flavicollis to 80% in M. agrestis. Sequence analysis revealed that the Bartonella strains belonged to the B. grahamii, B. taylorii, B. rochalimae, B. tribocorum, B. coopersplainsensis and B. doshiae genogroups. The highest Bartonella infection rates and the highest species diversity were both detected in rodents captured in the coastal area. To our knowledge, these are the first reports of the presence of B. coopersplainsensis, B. doshiae and B. tribocorum in Lithuania.