|
''Clostridium'' is a genus of Gram-positive species of pathogenic bacteria belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores.〔〔 Individual cells are rod-shaped, which gives them their name, from the Greek ''kloster'' (κλωστήρ) or spindle. These characteristics traditionally defined the genus; but many species originally classified as ''Clostridium'' have been reclassified in other genera. == Overview == ''Clostridium'' contains around 100 species〔 that include common free-living bacteria, as well as important pathogens.〔 The five main species responsible for disease in humans are: * ''C. botulinum'' can produce botulinum toxin in food or wounds and can cause botulism.〔 Honey sometimes contains spores of ''C. botulinum'', which may cause infant botulism in humans one year old and younger. The toxin eventually paralyzes the infant's breathing muscles.〔 Adults and older children can eat honey safely, because ''Clostridium'' species do not compete well with the other rapidly growing bacteria present in the gastrointestinal tract. This same toxin is known as Botox and is used cosmetically to paralyze facial muscles to reduce the signs of aging; it also has numerous therapeutic uses. * ''C. difficile'' can flourish when other bacteria in the gut are killed during antibiotic therapy, leading to pseudomembranous colitis (a cause of antibiotic-associated diarrhea).〔 * ''C. perfringens'', formerly called ''C. welchii'', causes a wide range of symptoms, from food poisoning to gas gangrene. It also causes enterotoxemia (also known as "overeating disease" or "pulpy kidney disease") in sheep and goats.〔 ''C. perfringens'' also takes the place of yeast in the making of salt rising bread. The name ''perfringens'' means 'breaking through' or 'breaking in pieces'. * ''C. tetani'' is the causative organism of tetanus.〔 The name is derived from , and τείνειν ''teinein'' "to stretch",〔 due to the violent spasms caused by ''C. tetani'' infection. * ''C. sordellii'' can cause a fatal infection in exceptionally rare cases after medical abortions.〔 Fewer than one case per year has been reported since 2000.〔 ''C. sordellii'' is sometimes found in raw swiftlet nests, a Chinese delicacy. Nests are washed in a sulfite solution to kill the bacteria before being exported to the U.S.〔 Neurotoxin production is the unifying feature of the species ''C. botulinum''. Eight types of toxins have been identified and allocated a letter (A-H).〔 Most strains produce one type of neurotoxin, but strains producing multiple toxins have been described. ''C. botulinum'' producing B and F toxin types have been isolated from human botulism cases in New Mexico and California. The toxin type has been designated Bf as the type B toxin was found in excess of the type F. Similarly, strains producing Ab and Af toxins have been reported. Organisms genetically identified as other ''Clostridium'' species have caused human botulism: ''Clostridium butyricum'' producing type E toxin and ''Clostridium baratii'' producing type F toxin. The ability of ''C. botulinum'' to naturally transfer neurotoxin genes to other ''Clostridium'' species is concerning, especially in the food industry where preservation systems are designed to destroy or inhibit only ''C. botulinum'', but not other ''Clostridium'' species. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clostridium」の詳細全文を読む スポンサード リンク
|