C Mc Kenzie F 2013 Modified by DYH

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C. Mc. Kenzie F 2013 Modified by DYH Bacterium: Clostridium botulinum • Division: Firmicutes

C. Mc. Kenzie F 2013 Modified by DYH Bacterium: Clostridium botulinum • Division: Firmicutes • endospore-forming • obligate anaerobic (can tolerate moderate oxygen levels due to anti-oxidant enzyme superoxide dismutase) • Mesophilic (optimal temperature approx. 37 C) • Rod-Shaped (exists individually, in pairs, or a linked chain) • Gram-positive bacteria. • Genome Size: 4, 039 kbp • • Larger than most Gram-positive bacteria due to presence of endospore (temperate phage) and botulin toxin (hemagglutinin A) Presence of transposon Tn 916 sites • 7 confirmed strains (A-G) composed in to 5 groups based on toxin subtype. • Recent discovery of what is believed to be a new, 8 th, strain – Type H • Sequence withheld from public because international threat due to lack of antidote. http: //microbewiki. kenyon. edu/images/thumb/7/77/B 2201272 Clostridium_botulinum_bacteria-SPL. jpg/400 px-B 2201272 Clostridium_botulinum_bacteria-SPL. jpg

C. botulinum Pathogenesis • Botulin exotoxin results in botulism • Types A, B &

C. botulinum Pathogenesis • Botulin exotoxin results in botulism • Types A, B & E are pathogenic in human (Groups 1 and 2 particularly) • Toxin is one of most powerful known: • One-millionth of a gram enough to kill average human • Methods of transmission: 3 • Aerosol (terrorism/chemical warfare); wound infection; and food borne ingestion (botulism and infant botulism) • Method of action: • Botulin toxin enters circulatory system and arrives at peripheral nerve synapses • At PNS synapse it blocks the release of neurotransmitter acetylcholine (ACh). • Without neural signaling skeletal muscles fail to contract and thus paralysis is induced. • Sold commercially for medical cosmetic procedures: • Toxin type A (Botox®, Dysport® and Xeomin®) and toxin type B (Myo. Bloc®) http: //www. studentpulse. com/articleimages/uploaded/324_1. jpg C. Mc. Kenzie F 2013 Modified by DYH