Query: NC_007799:968499 Ehrlichia chaffeensis str. Arkansas, complete genome
Lineage: Ehrlichia chaffeensis; Ehrlichia; Anaplasmataceae; Rickettsiales; Proteobacteria; Bacteria
General Information: This strain is the first isolate of Ehrlichia chaffeensis, which was obtained from a patient on an army base in Arkansas, USA in 1990. Causes disease in humans. This organism is an obligate intracellular pathogen that exists within vacuoles in the cytoplasm of monocytes or granulocytes. Transferred during an insect (tick) bite, it can cause disease in humans (human monocytic ehrlichiosis) and can reside in several other animals and is a problem in immunocompromised patients. The bacterium inhibits phagosome-lysozome fusion as well as programmed cell death (apoptosis) of the host cell, similar to what is observed with Anaplasma phagocytophilum.
Subject: NC_003366:2731995 Clostridium perfringens str. 13, complete genome
Lineage: Clostridium perfringens; Clostridium; Clostridiaceae; Clostridiales; Firmicutes; Bacteria
General Information: This strain is a type A isolate from the soil. It can establish gas gangrene in a murine experimental model. Causative agent of gas gangrene. This genus comprises about 150 metabolically diverse species of anaerobes that are ubiquitous in virtually all anoxic habitats where organic compounds are present, including soils, aquatic sediments and the intestinal tracts of animals and humans. This shape is attributed to the presence of endospores that develop under conditions unfavorable for vegetative growth and distend single cells terminally or sub-terminally. Spores germinate under conditions favorable for vegetative growth, such as anaerobiosis and presence of organic substrates. It is believed that present day Mollicutes (Eubacteria) have evolved regressively (i.e., by genome reduction) from gram-positive clostridia-like ancestors with a low GC content in DNA. This organism is a causative agent of a wide spectrum of necrotic enterotoxicoses. It also causes such animal diseases as lamb dysentery, ovine enterotoxemia (struck), pulpy kidney disease in lambs and other enterotoxemias in lambs and calves. It is commonly found in the environment (soil, sewage) and in the animal and human gastrointestinal tract as a member of the normal microflora. It is a fast growing (generation time 8-10 min) anaerobic flesh-eater. Active fermentative growth is accompanied by profuse generation of molecular hydrogen and carbon dioxide. It is also oxygen tolerant which makes it an easy object to work with in laboratories. Known isolates belong to five distinct types (A, B, C, D, and E) that are distinguished based on the specific extracellular toxins they produce. Known isolates belong to five distinct types (A, B, C, D, and E) that are distinguished based on the specific extracellular toxins they produce. All types produce the alpha toxin (phospholipase C). Type A strains that cause gas gangrene produce alpha toxin, theta (hemolysin), kappa (collagenase), mu (hyaluronidase), nu (DNAse) and neuraminidase which are all the enzymatic factors aiding the bacterium in invading and destruction of the host tissues. Type C strains produce alpha toxin, beta toxin and prefringolysin enteritis. In addition to alpha toxin, Type B strains produce beta toxin, types B and D produce the pore forming epsilon toxin and type E strains produce iota toxin.