クロストリジウム・パーフリンジェンス : 60 件 クロストリジウム・パーフリンゲンス : 70 件 perfringens パーフリンジェンス : 47 件 perfringens パーフリンゲンス : 63 件
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/06/20 22:43:47」(JST)
ウェルシュ菌 | |||||||||||||||||||||
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ウェルシュ菌のグラム染色像
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学名 | |||||||||||||||||||||
Clostridium perfringens (Veillon & Zuber 1898) |
ウェルシュ菌(ウェルシュきん、学名:Clostridium perfringens)とはクロストリジウム属に属する嫌気性桿菌である。河川、下水、海、土壌中など自然界に広く分布している[1]。ヒトを含む動物の腸内細菌叢における主要な構成菌であることが多い。少なくとも12種類の毒素を作り、α, β, ε, ιの4種の主要毒素の産生性によりA, B, C, D, E型の5つの型に分類される。Clostridium perfringens B型菌の毒素はヒツジの赤痢の原因となる。
かつてClostridium welchiiという学名で呼ばれていたことがある。ウィリアム・H・ウェルチ(英語版)が分離培養し1892年にBacillus aerogenes capsulatusと命名したが、後年ウェルチにちなんでBacterium welchii Migula 1900という学名が与えられ、ついでBacillus welchiiやClostridium welchiiと呼ばれるようになった。しかし命名規約上はBacterium welchiiよりも早く命名されたBacillus perfringens Veillon and Zuber 1898に優先権があるため、これが1937年にクロストリジウム属に移されて現在の学名として登録されている。
一般に、ビフィズス菌などと対比され、悪玉菌の代表とされている。臭い放屁の原因、悪玉の常在菌である。
グラム陽性非運動性偏性嫌気性であり、生体内または血清添加培地で増殖した場合、莢膜を形成する。一般に芽胞は形成されにくい。至適増殖温度は43-47℃。分裂時間は45℃で約10分間と短い。37℃で最も多くの毒素を産生する[1]。
A型菌はα毒素、B型菌はα, β, ε毒素、C型菌はα, β毒素、D型菌はα, ε毒素、E型菌はα, ι毒素を産生する。
ウェルシュ菌はその発症機序、病型により、ガス壊疽、出血性腸炎、エンテロトキセミア、食中毒の4種に区別される。
この項目は、真正細菌(バクテリア)に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています(Portal:生き物と自然/ウィキプロジェクト 生物)。 |
Clostridium perfringens | |
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Photomicrograph of gram-positive Clostridium perfringens bacilli. | |
Scientific classification | |
Kingdom: | Bacteria |
Phylum: | Firmicutes |
Class: | Clostridia |
Order: | Clostridiales |
Family: | Clostridiaceae |
Genus: | Clostridium |
Species: | C. perfringens |
Binomial name | |
Clostridium perfringens Veillon & Zuber 1898 |
Clostridium perfringens (formerly known as C. welchii, or Bacillus welchii) is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium.[1] C. perfringens is everpresent in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycollate medium.[2]
C. perfringens is the third most common cause of food poisoning in the United Kingdom and the United States though it can sometimes be ingested and cause no harm.
Infections due to C. perfringens show evidence of tissue necrosis, bacteremia, emphysematous cholecystitis, and gas gangrene, which is also known as clostridial myonecrosis. The toxin involved in gas gangrene is known as α-toxin, which inserts into the plasma membrane of cells, producing gaps in the membrane that disrupt normal cellular function. C. perfringens can participate in polymicrobial anaerobic infections. Clostridium perfringens is commonly encountered in infections as a component of the normal flora. In this case, its role in disease is minor.
The action of C. perfringens on dead bodies is known to mortuary workers as tissue gas and can be halted only by embalming.
In the United Kingdom and United States, C. perfringens bacteria are the third most common cause of foodborne illness, with poorly prepared meat and poultry, or food properly prepared but left to stand too long, the main culprits in harboring the bacterium.[3] The clostridium perfringens enterotoxin (CPE) mediating the disease is heat-labile (inactivated at 74 °C (165 °F)). It can be detected in contaminated food (if not heated properly), and feces.[4] Incubation time is between six and 24 (commonly 10-12) hours after ingestion of contaminated food.
Since C. perfringens forms spores that can withstand cooking temperatures, if cooked food is let stand for long enough, germination can ensue and infective bacterial colonies develop. Symptoms typically include abdominal cramping, diarrhea; vomiting and fever are usual. The whole course usually resolves within 24 hours. Very rare, fatal cases of clostridial necrotizing enteritis (also known as pigbel) have been known to involve "Type C" strains of the organism, which produce a potently ulcerative β-toxin. This strain is most frequently encountered in Papua New Guinea.
Many cases of C. perfringens food poisoning likely remain subclinical, as antibodies to the toxin are common among the population. This has led to the conclusion that most of the population has experienced food poisoning due to C. perfringens.
Despite its potential dangers, C. perfringens is used as the leavening agent in salt rising bread. The baking process is thought to reduce the bacterial contamination, precluding negative effects.
Clostridium perfringens is the most common bacterial agent for gas gangrene, which is necrosis, putrefaction of tissues, and gas production. It is caused primarily by Clostridium perfringens alpha toxin. The gases form bubbles in muscle (crepitus) and the characteristic smell in decomposing tissue. After rapid and destructive local spread (which can take only hours), systemic spread of bacteria and bacterial toxins may cause death. This is a problem in major trauma and in military contexts. C. perfringens grows readily on blood agar plate in anaerobic conditions, and often produces a double zone of beta hemolysis.
Research published in 2014 suggested that a strain of C. perfringens might be implicated in multiple sclerosis (MS). Tests in mice found that a toxin made by a rare strain of C. perfringens caused MS-like damage in the brain, and earlier work had identified this strain of C. perfringens in a human with MS.[5] MS patients were found to be ten times more immune-reactive to the epsilon toxin than healthy people.[6]
C. perfringens can be diagnosed by Nagler's reaction where the suspect organism is cultured on an egg yolk media plate. One side of the plate contains anti-alpha-toxin, while the other side does not. A streak of suspect organism is placed through both sides. An area of turbidity will form around the side that does not have the anti-alpha-toxin, indicating uninhibited lecithinase activity. Other tests/reactions: Catalase: Negative, Spot indole: Positive, Lecithinase: Positive, Lipase: Negative, Litmus Milk: Stormy Fermentation, Reverse CAMP plate: Positive, Gas Liquid Chromatography products: (Acetic, Butyric and Lactic Acids).
If suspected on clinical grounds, treatment should begin without waiting for lab results. Traumatic wounds should be cleaned. Wounds that cannot be cleaned should not be stitched shut. Penicillin prophylaxis kills many clostridia and is thus useful for dirty wounds and lower leg amputations. A high infectious dose is required; the carrier state persists for several days.
On May 7, 2010, 42 residents and 12 staff members at a Louisiana state psychiatric hospital experienced vomiting, abdominal cramps, and diarrhea. Within 24 hours, three patients had died. The outbreak was linked to chicken which was cooked a day prior to being served and was not cooled down according to hospital guidelines. The outbreak affected 31% of the residents of the hospital and 69% of the staff who ate the chicken. It is unknown how many of the affected residents ate the chicken.[7]
In May 2011, a man died after allegedly eating food contaminated with the bacteria on a transatlantic American Airlines flight. The man's wife and daughter are suing American and LSG Sky Chefs, the German company that prepared the inflight food.[8]
In December 2012, a 46-year-old woman died two days after eating a Christmas Day meal at a pub in Hornchurch, Essex, England. She was among about 30 people to fall ill after eating the meal. Samples taken from the victims contained C.perfringens. The woman's husband said that he intended to take legal action over his wife's death.[9]
In December 2014, 87 year old Bessie Scott died three days after eating a church potluck supper in Nackawic, New Brunswick, Canada. Over 30 other people reported signs of gastrointestinal illness, diarrhea and abdominal pain. The province's acting chief medical officer says Clostridium perfringens is the bacteria that most likely caused the woman’s death.[10]
And also now by Anas Abdullahi Jargaba i suggest that the mojor time this bacteria c.perfringes is ...
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国試過去問 | 「110A038」 |
リンク元 | 「細菌」「クリンダマイシン」「急性胃腸炎」「クロストリジウム属」「クロストリジウム性ガス壊疽」 |
関連記事 | 「clostridium」「Clostridium」 |
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※国試ナビ4※ [110A037]←[国試_110]→[110A039]
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