Genomic characterization of eight novel Bartonella species from bats and ectoparasites reveals phylogenetic diversity and host adaptation

Bats are recognized as hosts of diverse Bartonella species, and Bartonella are known agents of human disease. Here, we reported the isolation of 26 Bartonella strains belonging to eight distinct species from two bat species (Myotis laniger and M. adversus) and their ectoparasites (bat flies and bat mites) collected from Chongming County, Hubei Province, China. We obtained whole genome sequences of the bat-borne Bartonella spp. with second and third generation sequencing. The genome size of the bat-borne Bartonella spp. ranged from 1.39 to 1.98 Mb, with the GC content from 35.30%-38.92%. Phylogenetic analysis revealed that the bat-borne Bartonella spp. were divergent from currently known Bartonella spp., and the Average Nucleotide Identity (ANI) values were all below 95%, indicating that they were all novel species. Comparative genomic analysis underscored distinct characteristics of bat-borne Bartonella spp. in cell motility, replication, recombination, and the biogenesis of the cell wall/membrane/envelope, suggesting that bat-borne Bartonella spp. exhibited unique host adaptability. Notably, the virulence factor genes of two bat-borne Bartonella spp., strains B23 and 39, were highly analogous to those of the currently known Bartonella henselae and Bartonella quintana, indicating that they might be pathogenic to humans and animals. Altogether, our findings significantly broaden the diversity of the Bartonella genus, and provide new insights into the host specificity and evolutionary relationship of bat-borne Bartonella spp..