Query: NC_017044:130000 Rickettsia parkeri str. Portsmouth chromosome, complete genome
Lineage: Rickettsia parkeri; Rickettsia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: Animal pathogen in Mammalia (intracellular obligate). Rickettsiae are obligate intracellular Gram-negative bacteria mostly found in arthropods, some of which cause mild to severe diseases in humans. Rickettsia parkeri, a member of the spotted fever group Rickettsia (SFGR), was first isolated from the Gulf Coast tick, Amblyomma maculatum, in 1937. In 2004, the first confirmed human infection with R. parkeri was reported in a 40-year-old man from the Tidewater area of coastal Virginia. The agent was isolated in cell culture from an eschar biopsy specimen and designated the Portsmouth strain; recently, the first recognized case of tick bite-associated human infection was described.
Subject: NC_010161:2050816 Bartonella tribocorum CIP 105476, complete genome
Lineage: Bartonella tribocorum; Bartonella; Bartonellaceae; Rhizobiales; Proteobacteria; Bacteria
General Information: This organism was isolated from the blood of wild rats and from fleas obtained from wild rats. Transmission of these organisms is often through an insect vector. Once in a host, this intracellular pathogen is internalized by an actin-dependent mechanism, and primarily targets endothelial cells, although other cells can be infected. The proliferation of the vascular endothelium (bacillary angiomatosis) is characterisitic of Bartonella infection and results in multiplication of the bacterium's host cells. Infected macrophages are stimulated to release vascular endothelial growth factor (VEGF) and interleukin 1 beta, both of which promote angiogenesis. Endothelial cells are also stimulated to grow and divide by direct contact with bacterial cells. In addition, programmed cell death (apoptosis) of endothelial cells is inhibited, combatting a common mechanism eukaryotic cells use to deal with bacterial infection. Other pathogenicity factors include pili and outer membrane adhesins for attachment to host cells. This organism is genetically related to Bartonella elizabethae which was isolated from a case of endocarditis in a human.