Genetic characterization of Bartonella spp. from rodents

Abstract

Bartonella are facultative intracellular, fastidious, gram-negative bacteria that are transmitted to mammals and humans by bloodsucking arthropod vectors. Currently, 45 official and candidate Bartonella species have been detected in vertebrates, and at least twenty of them have been detected in rodents. Several rodent-associated Bartonella species have been related to human diseases. However, there is a lack of studies on the presence and diversity of Bartonella spp. in rodents from Baltic region. We analyzed 580 individuals belonging to eight small rodent species, trapped in Lithuania during 2015 – 2016. The presence of Bartonella DNA was examined by real-time PCR targeting the ssrA gene. Species identification and molecular characterization of bacteria strains were based on sequence analysis of two housekeeping genes (rpoB, groEL) and the intergenic species region. Sequence analysis reveal that rodents harbor multiple Bartonella species belonging to six clades, including Bartonella grahamii, Bartonella taylorii, Bartonella tribocorum, Bartonella coopersplasensis, Bartonella doshiae and Bartonella rochalimae. Phylogenetic analysis showed the presence of different B. grahamii, B. taylorii and B. tribocorum genotypes associated with different host species and demonstrated that in rodent communities circulate more than one bacteria genetic variant, and multiple Bartonella genotypes found in the same reservoir species. Our study represents the first genetic characterization of Bartonella strains circulating in rodents in the Baltic countries.