Small pleomorphic Gram-negative bacilli that belong to the α-2 subdivision of Proteobacteria.
A wide range of domestic and wild animals such as cats, dogs, mice, rats, squirrels, deer, and moose serves as reservior hosts for the 22 described species. The number of species identified is still expanding.
The three major human pathogens are the human-specific Bartonella bacilliformis and Bartonella quintana and the cat-specific Bartonella henselae, where humans appear as incidental hosts.
Facultative intracellular pathogen
A paradigm for pathogen-triggered vascular tumour formation
The common theme of Bartonella infections in the reservoir host is the long-lasting intraerythrocytic bacteremia.
Both in the incidental and the reservoir host, Bartonella interacts also with endothelial cells which in a immunocompromized individual can cause vasoproliferative lesions like verruga peruana in the case of B. bacilliformis or bacillary angiomatosis in the case of B. quintana and B. henselae.
B. bacilliformis: Carrion's disease: Oroya fever and verruga peruana
B. quintana: trench fever, endocarditis, bacillary angiomatosis
B. henselae: cat-scratch disease
Genomes (comparative pathogenomics):
B. bacilliformis KC583, 1445021 bp, NC_008783
B. henselae str. Houston-1, 1931047 bp, NC_005956
B. quintana str. Toulouse, 1581384 bp, NC_005955
B. tribocorum CIP 105476, 2619061 bp, NC_010161
Alsmark CM, et al., 2004. The louse-borne human pathogen Bartonella quintana is a genomic derivative of the zoonotic agent Bartonella henselae. Proc. Natl. Acad. Sci. USA 101(26):9716-9721.
Saenz HL, et al., 2007. Genomic analysis of Bartonella identifies type IV secretion systems as host adaptability factors. Nat Genet 39(12):1469-1476.
Major virulence factors in Bartonella:
Flagella (B. bacilliformis)
Trw type IV secretion system
VirB/VirD4 type IV secretion system
Location of virulence-associated genes in B. henselae: