Query: NC_008149:587689 Yersinia pestis Nepal516, complete genome
Lineage: Yersinia pestis; Yersinia; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
General Information: Isolated from a soil sample from Nepal. Causative agent of plague. Specific virulence factors are encoded within pathogenicity islands (PAIs) that are required for the invasive phenotype associated with Yersinia infections. One key virulence plasmid contained by the three human-specific pathogens is pCD1/pYv, which encodes a type III secretion system for the delivery of virulence proteins that contribute to internalization into the host cell. It is the causative agent of plague (bubonic and pulmonary) a devastating disease which has killed millions worldwide. The organism can be transmitted from rats to humans through the bite of an infected flea or from human-to-human through the air during widespread infection. Yersinia pestis is an extremely pathogenic organism that requires very few numbers in order to cause disease, and is often lethal if left untreated. The organism is enteroinvasive, and can survive and propagate in macrophages prior to spreading systemically throughout the host. Yersinia pestis consists of three biotypes or serovars, Antiqua, Mediavalis, and Orientalis, that are associated with three major pandemics throughout human history. pMT1 encodes a protein, murine toxin, that aids rat-to-human transmission by enhancing survival of the organism in the flea midgut. Yersinia pestis also contains a PAI on the chromosome that is similar to the SPI-2 PAI from Salmonella that allows intracellular survival in the organism.
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.