Dictionary:

clostridium

  (klŏ-strĭd'ē-əm)

Also from Answers.com... Home First Aid/Health at Home What every household needs to be safe.

Any of various rod-shaped, spore-forming, chiefly anaerobic bacteria of the genus Clostridium, such as the nitrogen-fixing bacteria found in soil and those causing botulism and tetanus.

[New Latin Clōstridium, genus name, from Greek klōstēr, klōstr-, spindle, from klōthein, to spin.]

A genus of bacteria comprising large anaerobic spore-forming rods that usually stain gram-positive. Most species are anaerobes, but a few will grow minimally in air at atmospheric pressure.

The clostridia are widely distributed in nature, and are present in the soil and in the intestinal tracts of humans and animals. They usually live a saprophytic existence, and play a major role in the degradation of organic material in the soil and other nature environments. A number of clostridia release potent exotoxins and are pathogenic for humans and animals. Among the human pathogens are the causative agents of botulism (Clostridium botulinum), tetanus (C. tetani), gas gangrene (C. perfringens), and an antibiotic-associated enterocolitis (C. difficile). See also Anaerobic infection; Botulism; Toxin.

Clostridial cells are straight or slightly curved rods, 0.3–1.6 micrometers wide and 1–14 μm long. They may occur singly, in pairs, in short or long chains, or in helical coils. The length of the cells of the individual species varies according to the stage of growth and growth conditions. Most clostridia are motile with a uniform arrangement of flagella. See also Cilia and flagella.

The endospores produced by clostridia are dormant structures capable of surviving for prolonged periods of time, and have the ability to reestablish vegetative growth when appropriate environmental conditions are provided. The spores of clostridia are oval or spherical and are wider than the vegetative bacterial cell. Among the distinctive forms are spindle-shaped organisms, club-shaped forms, and tennis racket-shaped structures:

Clostridia are obligate anaerobes: they are unable to use molecular oxygen as a final electron acceptor and generate their energy solely by fermentation. Clostridia exhibit varying degrees of intolerance of oxygen. Some species are sensitive to oxygen concentrations as low as 0.5%, but most species can tolerate concentrations of 3–5%. The sensitivity of clostridia to oxygen restricts their habitat to anaerobic environments; habitats that contain large amounts of organic matter provide optimal conditions for their growth and survival.

A primary property of all species of Clostridium is their inability to carry out a dissimilatory reduction of sulfate. Most species are chemoorganotrophic. The substrate spectrum for the genus as a whole is very broad and includes a wide range of naturally occurring compounds. Extracellular enzymes are secreted by many species, enabling the organism to utilize a wide variety of complex natural substrates in the environment.

A genus of bacteria, of which C. botulinum is responsible for botulism, a rare but often fatal form of food poisoning. It is found widely distributed in soil; during growth on favourable food materials, the organism synthesizes an extremely potent neurotoxin which is released into the food when the cell dies. The spores are extremely heat-resistant and their thermal death time is used as a minimum standard for processing foods with pH values higher than 4.5.

A genus of spore-forming anaerobic bacteria of the Bacillaceae family.

For more information on clostridium, visit Britannica.com.

Pertaining to or emanating from infection by Clostridium spp.

• c. dermatomyositis — see malignant edema.
• c. enteritis — see enterotoxemia.
• c. food poisoning — diarrhea in humans caused by ingestion of preformed toxin produced by C. perfringens type A.
• c. gangrenous dermatitis — see blue wing disease.
• c. gas gangrene — see histotoxic clostridia.
• c. hemoglobinuria — see bacillary hemoglobinuria.
• c. intestinal hemorrhage syndrome of dogs — see canine hemorrhagic gastroenteritis.
• c. myositis — see blackleg.
• c. necrotic enteritis — caused in birds by Clostridium perfingens types A and C. Characterized by short course with severe depression, diarrhea and high mortality and necropsy findings of pseudomembranous enteritis.
• c. swelled head — see ovine bighead.
• c. ulcerative enteritis — a disease of quail caused by Clostridium colinum. Characterized in young quail by acute hemorrhagic enteritis and very high case fatality and morbidity rates. Necrosis and ulceration of the intestinal wall occur in birds which survive for several days.

Clostridium
SEM micrograph of Clostridium difficile colonies from a stool sample.
Scientific classification
Kingdom: Bacteria Phylum: Firmicutes Class: Clostridia Order: Clostridiales Family: Clostridiaceae Genus: Clostridium Prazmowski 1880
Species
C. acetobutylicum C. aerotolerans C. botulinum C. butyricum C. colicanis C. difficile C. formicaceticum C. ljungdahlii C. laramie C. novyi C. perfringens C. piliforme C. sordellii C. sporogenes C. tetani C. tyrobutyricum

Clostridium is a large genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores.^[1] Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle. These characteristics traditionally defined the genus, but they are not phylogenetically significant; many species originally classified as Clostridium have been reclassified in other genera.

Pathology

Clostridium includes common free-living bacteria as well as important pathogens.^[2] There are four main species responsible for disease in humans:

• C. botulinum, an organism producing a toxin in food that causes botulism.^[3]

• C. difficile, which can overgrow other bacteria in the gut during antibiotic therapy, can cause pseudomembranous colitis.^[4]

• C. perfringens, causes a wide range of symptoms, from food poisoning to gas gangrene. Also responsible for enterotoxemia (also known as "overeating disease" or "pulpy kidney disease") in sheep and goats.^[5]

• C. tetani, the causative organism of tetanus (lockjaw).^[6]

Honey sometimes contains Clostridium bacteria which may cause infant botulism in humans one year old and under. Infant botulism causes the infant to produce botulinium toxin, which eventually paralyzes the breathing muscles.^[7] C. sordellii has been linked to the deaths of more than a dozen women after childbirth.

Commercial uses

C. thermocellum can utilize lignocellulosic waste and generate ethanol, thus making it a possible candidate for use in ethanol production. It also has no oxygen requirement and is thermophilic, reducing cooling cost. C. acetobutylicum, also known as the Weizmann organism, which was first used by Chaim Weizmann to produce acetone and biobutanol from starch in 1916 for the production of gunpowder and TNT.

The anaerobic bacterium C. ljungdahlii, recently discovered in commercial chicken wastes, can produce ethanol from single-carbon sources including synthesis gas, a mixture of carbon monoxide and hydrogen that can be generated from the partial combustion of either fossil fuels or biomass. Use of these bacteria to produce ethanol from synthesis gas has progressed to the pilot plant stage at the BRI Energy facility in Fayetteville, Arkansas.^[8]

References

1. ^ Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill. ISBN 0-8385-8529-9. 
2. ^ Wells CL, Wilkins TD (1996). Clostridia: Sporeforming Anaerobic Bacilli in: Baron's Medical Microbiology (Baron S et al, eds.), 4th ed., Univ of Texas Medical Branch. ISBN 0-9631172-1-1. 
3. ^ Wells CL, Wilkins TD (1996). Botulism and Clostridium botulinum in: Baron's Medical Microbiology (Baron S et al, eds.), 4th ed., Univ of Texas Medical Branch. ISBN 0-9631172-1-1. 
4. ^ Wells CL, Wilkins TD (1996). Antibiotic-Associated Diarrhea, Pseudomembranous Colitis, and Clostridium difficile in: Baron's Medical Microbiology (Baron S et al, eds.), 4th ed., Univ of Texas Medical Branch. ISBN 0-9631172-1-1. 
5. ^ Wells CL, Wilkins TD (1996). Other Pathogenic Clostridia Food Poisoning and Clostridium perfringens in: Baron's Medical Microbiology (Baron S et al, eds.), 4th ed., Univ of Texas Medical Branch. 
6. ^ Wells CL, Wilkins TD (1996). Tetanus and Clostribium tetani in: Baron's Medical Microbiology (Baron S et al, eds.), 4th ed., Univ of Texas Medical Branch. ISBN 0-9631172-1-1. 
7. ^ Tanzi MG, Gabay MP (2002). "Association between honey consumption and infant botulism". Pharmacotherapy 22 (11): 1479-83. PMID 12432974. 
8. ^ Providing for a Sustainable Energy Future. Bioengineering Resources, inc. Retrieved on 21 May 2007.

External links

• Todar's Online Textbook of Bacteriology
• UK Clostridium difficile Support Group
• Pathema-Clostridium Resource
• Water analysis: Clostridium video

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)