Query: NC_011244:213853 Borrelia recurrentis A1, complete genome
Lineage: Borrelia recurrentis; Borrelia; Spirochaetaceae; Spirochaetales; Spirochaetes; Bacteria
General Information: Borrelia recurrentis isolated from adult patient with louse-borne relapsing fever in Ethiopia. Borrelia recurrentis is the causative agent of louse-borne relapsing fever. Prior to World War II, this organism was responsible for large disease outbreaks with a mortality of up to 40% in much of the world. Currently this disease is limited to parts of Africa, China, and Peru. B. recurrentis is transmitted when infected human body lice (Pediculus humanus) are crushed and their fluids contaminate mucous membranes or breaks in the skin. Relapsing fever is characterized by a period of chills, fever, headache, and malaise, an asymptomatic period, followed by another episode of symptoms. This cycle of relapsing is due to changes in the surface proteins of Borrelia, which allow it to avoid detection and removal by the host immune system. This antigenic variation is the result of homologous recombination of silent proteins into an expressed locus, causing partial or complete replacement of one serotype with another.
Subject: NC_009727:357206 Coxiella burnetii Dugway 7E9-12, complete genome
Lineage: Coxiella burnetii; Coxiella; Coxiellaceae; Legionellales; Proteobacteria; Bacteria
General Information: Coxiella burnetii Dugway 5J108-111 was isolated from rodents in Utah, USA. This organism is widely distributed in nature and can cause infections in reptiles, birds, and mammals. It causes Q fever, or 'query' fever, an atypical pneumonia first associated with abattoir workers in Australia. Transmission may be through insect vectors such as ticks that have bitten an infected wild or domesticated animal, or through an aerosol produced by domesticated animals such as sheep or cattle. The presence of a plasmid is believed to be associated with virulence and pathogenicity, however C. burnetii isolates containing plasmid QpDG are avirulent in guinea pigs and plasmidless isolates have been associated with endocarditis in humans. Coxiella burnetii has a developmental life cycle, and can grow vegetatively through binary fission, or asymmetrically and produce a spore-like cell. The spore-like cell may enable the organism to exist extracellularly for small amounts of time. This bacterium is an obligate intracellular pathogen. It is endocytosed by a host cell, a macrophage for example, and lives and replicates inside the phagolysozome, a unique property of this organism. The genome encodes proteins that have a higher than average pI, which may enable adaptation to the acidic environment of the phagolysozome. The chromosome also contains genes for a number of detoxification and stress response proteins such as dismutases that allow growth in the oxidative environment. The type IV system is similar to the one found in Legionella, which may be important for intracellular survival. This organism produces numerous ankyrin-repeat proteins that may be involved in interactions with the host cell. The genome has 83 pseudogenes, which may be a result of the typical genome-wide degradation observed with other intracellular organisms and also has a group I intron in the 23S ribosomal RNA gene.