Clostridium Health Dictionary

Clostridium: From 3 Different Sources


Any of a group of rodshaped bacteria.

Clostridia are found in soil and in the gastrointestinal tracts of humans and animals.

They produce powerful toxins and are responsible for potentially life-threatening diseases such as botulism, tetanus, and gangrene.

Health Source: BMA Medical Dictionary
Author: The British Medical Association
The genus, or variety, of micro-organisms that produce spores which enable them to survive under adverse conditions. They normally grow in soil, water and decomposing plant and animal matter, where they play an important part in the process of PUTREFACTION. Among the important members of the group, or genus, are Clostridium welchii, Cl. septicum and Cl. oedematiens, the causes of gas gangrene (see GANGRENE); Cl. tetani, the cause of TETANUS; and Cl. botulinum, the cause of BOTULISM.
Health Source: Medical Dictionary
Author: Health Dictionary
n. a genus of mostly Gram-positive anaerobic spore-forming rodlike bacteria commonly found in soil and in the intestinal tract of humans and animals. Many species cause disease and produce extremely potent *exotoxins. C. botulinum grows freely in badly preserved canned foods, producing a toxin causing serious food poisoning (*botulism); an extremely dilute form of this toxin is now used to treat muscle spasm (see botulinum toxin). C. histolyticum, C. oedematiens, and C. septicum all cause *gas gangrene when they infect wounds. C. tetani lives as a harmless *commensal in the intestine but causes *tetanus on contamination of wounds (with manured soil). The species C. perfringens – Welch’s bacillus – causes blood poisoning, *food poisoning, and gas gangrene. Overgrowth of Clostridium difficile (often shortened to C. diff), a normal inhabitant of the human large intestine, is not uncommon as a complication of some antibiotic therapy and produces a specific condition – pseudomembranous colitis (see pseudomembrane) – which is life-threatening unless treated promptly and is becoming more common as a hospital-acquired infection.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Tetanus

An infective disease due to the toxins of Clostridium tetani... tetanus

Botulinum Toxin

The toxin of the anaerobic bacterium CLOSTRIDIUM botulinum is now routinely used to treat focal DYSTONIA in adults. This includes blepharospasm (see EYE, DISORDERS OF), SPASMODIC TORTICOLLIS, muscular spasms of the face, squint and some types of tremor. Injected close to where the nerve enters the affected muscles, the toxin blocks nerve transmissions for up to four months, so relieving symptoms. The toxin is also used in cerebral palsy. Although very e?ective, there are many possible unwanted effects, especially if too high a dose is used or the injection is misplaced.... botulinum toxin

Botulism

A rare type of food poisoning with a mortality greater than 50 per cent, caused by the presence of the exotoxin of the anaerobic bacterium Clostridium botulinum, usually in contaminated tinned or bottled food. Symptoms develop a few hours after ingestion.

The toxin has two components, one having haemagglutinin activity and the other neurotoxic activity which produces most of the symptoms. It has a lethal dose of as little as 1 mg/kg and is highly selective for cholinergic nerves. Thus the symptoms are those of autonomic parasympathetic blockade (dry mouth, constipation, urinary retention, mydriasis, blurred vision) and progress to blockade of somatic cholinergic transmission (muscle weakness). Death results from respiratory muscle paralysis. Treatment consists of supportive measures and 4 aminopyridine and 3, 4 di-aminopyridine, which may antagonise the e?ect of the toxin.... botulism

Colitis

In?ammation of the colon, the ?rst part of the large intestine. The subject suffers from diarrhoea, usually passing blood and mucus, abdominal pain or discomfort, and fever. Colitis can be caused by various micro-organisms: for example, CAMPYLOBACTER, CLOSTRIDIUM and SHIGELLA bacteria, viruses or amoeba. Anxiety and antibiotic drugs may also cause colitis, the latter by directly irritating the lining of the gut.

Colitis is classi?ed as an INFLAMMATORY BOWEL DISEASE (IBD) and ULCERATIVE COLITIS is a particularly troublesome form, the cause of which is not known. CROHN’S DISEASE may also cause colitis and is included in the umbrella designation IBD (see also IRRITABLE BOWEL SYNDROME (IBS)).... colitis

Food Poisoning

This illness is characterised by vomiting, diarrhoea and abdominal pain, and results from eating food contaminated with metallic or chemical poisons, certain micro-organisms or microbial products. Alternatively, the foods – such as undercooked red kidney beans or ?sh of the scombroid family (mackerel and tuna) – may contain natural posions. Food poisoning caused by chemical or metallic substances usually occurs rapidly, within minutes or a few hours of eating. Among micro-organisms, bacteria are the leading cause of food poisoning, particularly Staphylococcus aureus, Clostridium perfringens (formerly Cl. welchii), Salmonella spp., Campylobacter jejuni, and Escherichia coli O157.

Staphylococcal food poisoning occurs after food such as meat products, cold meats, milk, custard and egg products becomes contaminated before or after cooking, usually through incorrect handling by humans who carry S. aureus. The bacteria produce an ENTEROTOXIN which causes the symptoms of food poisoning 1–8 hours after ingestion. The toxin can withstand heat; thus, subsequent cooking of contaminated food will not prevent illness.

Heat-resistant strains of Cl. perfringens cause food poisoning associated with meat dishes, soups or gravy when dishes cooked in bulk are left unrefrigerated for long periods before consumption. The bacteria are anaerobes (see ANAEROBE) and form spores; the anaerobic conditions in these cooked foods allow the germinated spores to multiply rapidly during cooling, resulting in heavy contamination. Once ingested the bacteria produce enterotoxin in the intestine, causing symptoms within 8–24 hours.

Many di?erent types of Salmonella (about 2,000) cause food poisoning or ENTERITIS, from eight hours to three days after ingestion of food in which they have multiplied. S. brendeny, S. enteritidis, S. heidelberg, S. newport and S. thompson are among those commonly causing enteritis. Salmonella infections are common in domesticated animals such as cows, pigs and poultry whose meat and milk may be infected, although the animals may show no symptoms. Duck eggs may harbour Salmonella (usually S. typhimurium), arising from surface contamination with the bird’s faeces, and foods containing uncooked or lightly cooked hen’s eggs, such as mayonnaise, have been associated with enteritis. The incidence of human S. enteritidis infection has been increasing, by more than 15-fold in England and Wales annually, from around 1,100 a year in the early 1980s to more than 32,000 at the end of the 1990s, but has since fallen to about 10,000. A serious source of infection seems to be poultry meat and hen’s eggs.

Although Salmonella are mostly killed by heating at 60 °C for 15 minutes, contaminated food requires considerably longer cooking and, if frozen, must be completely thawed beforehand, to allow even cooking at a su?cient temperature.

Enteritis caused by Campylobacter jejuni is usually self-limiting, lasting 1–3 days. Since reporting of the disease began in 1977, in England and Wales its incidence has increased from around 1,400 cases initially to nearly 13,000 in 1982 and to over 42,000 in 2004. Outbreaks have been associated with unpasteurised milk: the main source seems to be infected poultry.

ESCHERICHIA COLI O157 was ?rst identi?ed as a cause of food poisoning in the early 1980s, but its incidence has increased sharply since, with more than 1,000 cases annually in the United Kingdom in the late 1990s. The illness can be severe, with bloody diarrhoea and life-threatening renal complications. The reservoir for this pathogen is thought to be cattle, and transmission results from consumption of raw or undercooked meat products and raw dairy products. Cross-infection of cooked meat by raw meat is a common cause of outbreaks of Escherichia coli O157 food poisoning. Water and other foods can be contaminated by manure from cattle, and person-to-person spread can occur, especially in children.

Food poisoning associated with fried or boiled rice is caused by Bacillus cereus, whose heat-resistant spores survive cooking. An enterotoxin is responsible for the symptoms, which occur 2–8 hours after ingestion and resolve after 8–24 hours.

Viruses are emerging as an increasing cause of some outbreaks of food poisoning from shell?sh (cockles, mussels and oysters).

The incidence of food poisoning in the UK rose from under 60,000 cases in 1991 to nearly 79,000 in 2004. Public health measures to control this rise include agricultural aspects of food production, implementing standards of hygiene in abattoirs, and regulating the environment and process of industrial food production, handling, transportation and storage.... food poisoning

Gangrene

The death and decay of body tissues caused by a de?ciency or cessation of the blood supply. There are two types: dry and moist. The former is a process of mummi?cation, with the blood supply of the affected area of tissue stopping and the tissue withering up. Moist gangrene is characterised by putrefactive tissue decay caused by bacterial infection. The dead part, when formed of soft tissues, is called a slough and, when part of a bone, is called a sequestrum.

Causes These include injury – especially that sustained in war – disease, FROSTBITE, severe burns, ATHEROMA in large blood vessels, and diseases such as DIABETES MELLITUS and RAYNAUD’S DISEASE. Gas gangrene is a form that occurs when injuries are infected with soil contaminated with gas-producing bacilli such as Clostridium welchii, which are found in well-cultivated ground.

Treatment Dry gangrene must be kept dry, and AMPUTATION of the dead tissue performed when a clear demarcation line with healthy tissue has formed. Wet gangrene requires urgent surgery and prompt use of appropriate antibiotics.... gangrene

Gram’s Stain

Bacteria can be stained with an iodine-based chemical dye called Gram’s stain (after the scientist who discovered the technique). Different bacteria react di?erently to exposure to the stain. Broadly, the bacterial specimens are stained ?rst with gentian violet, then with Gram’s stain, and ?nally counterstained with a red dye after a decolorising process. Bacteria that retain the gentian stain are called gram-positive; those that lose it but absorb the red stain are called gram-negative. Some species of staphylococcus, streptococcus and clostridium are gram-positive, whereas salmonella and Vibrio cholerae are gram-negative.... gram’s stain

Spore

Part of the lifecycle of certain BACTERIA when the vegetative cell is encapsulated and metabolism falls to a low level. The spore is resistant to changes in the environment and, when these are unfavourable, the spore remains dormant; when they improve, it starts to grow. Certain dangerous bacteria, such as CLOSTRIDIUM, produce resistant ubiquitous spores, so sterilisation procedures need to be very e?ective.... spore

Cdh

1. see congenital diaphragmatic hernia. 2. see congenital dislocation of the hip.

C. diff Clostridium difficile. See Clostridium.... cdh

Clindamycin

n. an antibiotic used to treat serious bacterial infections, such as staphylococcal bone and joint infections. The most serious side-effect is pseudomembranous colitis, caused by overgrowth of *Clostridium difficile, which limits the use of this drug; other side-effects include nausea, vomiting, and occasional hypersensitivity reactions.... clindamycin

Endospore

n. the resting stage of certain bacteria, particularly species of the genera Bacillus and Clostridium. In adverse conditions the bacterium can become enclosed within a tough protective coat, allowing the cell to survive. On return of favourable conditions the spore changes back to the vegetative form.... endospore

Gas Gangrene

death and decay of wound tissue infected by the soil bacterium *Clostridium perfringens. Toxins produced by the bacterium cause putrefactive decay of connective tissue with the generation of gas. Treatment is usually by surgery.... gas gangrene

Nosocomial Infection

(hospital infection) an infection that originates in a hospital. It may develop in a hospitalized patient or a member of the hospital staff, or it may be acquired in hospital but only develops after discharge. Such infections include those caused by fungi and opportunist bacteria. They are aggravated by factors favouring the spread of organisms (cross-contamination), such as insufficient hand washing among medical staff, and by reduced resistance of individual patients, as well as by antibiotic-resistant strains of bacteria (see Clostridium; Enterococcus; MRSA).... nosocomial infection

Diarrhoea

Diarrhoea or looseness of the bowels is increased frequency, ?uidity or volume of bowel movements compared to usual. Most people have occasional attacks of acute diarrhoea, usually caused by contaminated food or water or excessive alcohol consumption. Such attacks normally clear up within a day or two, whether or not they are treated. Chronic diarrhoea, on the other hand, may be the result of a serious intestinal disorder or of more general disease.

The commonest cause of acute diarrhoea is food poisoning, the organisms involved usually being STAPHYLOCOCCUS, CLOSTRIDIUM bacteria, salmonella, E. coli O157 (see ESCHERICHIA), CAMPYLOBACTER, cryptosporidium, and Norwalk virus. A person may also acquire infective diarrhoea as a result of droplet infections from adenoviruses or echoviruses. Interference with the bacterial ?ora of the intestine may cause acute diarrhoea: this often happens to someone who travels to another country and acquires unfamiliar intestinal bacteria. Other infections include bacillary dysentery, typhoid fever and paratyphoid fevers (see ENTERIC FEVER). Drug toxicity, food allergy, food intolerance and anxiety may also cause acute diarrhoea, and habitual constipation may result in attacks of diarrhoea.

Treatment of diarrhoea in adults depends on the cause. The water and salts (see ELECTROLYTES) lost during a severe attack must be replaced to prevent dehydration. Ready-prepared mixtures of salts can be bought from a pharmacist. Antidiarrhoeal drugs such as codeine phosphate or loperamide should be used in infectious diarrhoea only if the symptoms are disabling. Antibacterial drugs may be used under medical direction. Persistent diarrhoea – longer than a week – or blood-stained diarrhoea must be investigated under medical supervision.

Diarrhoea in infants can be such a serious condition that it requires separate consideration. One of its features is that it is usually accompanied by vomiting; the result can be rapid dehydration as infants have relatively high ?uid requirements. Mostly it is causd by acute gastroenteritis caused by various viruses, most commonly ROTAVIRUSES, but also by many bacteria. In the developed world most children recover rapidly, but diarrhoea is the single greatest cause of infant mortality worldwide. The younger the infant, the higher the mortality rate.

Diarrhoea is much more rare in breast-fed babies, and when it does occur it is usually less severe. The environment of the infant is also important: the condition is highly infectious and, if a case occurs in a maternity home or a children’s hospital, it tends to spread quickly. This is why doctors prefer to treat such children at home but if hospital admission is essential, isolation and infection-control procedures are necessary.

Treatment An infant with diarrhoea should not be fed milk (unless breast-fed, when this should continue) but should be given an electrolyte mixture, available from pharmacists or on prescription, to replace lost water and salts. If the diarrhoea improves within 24 hours, milk can gradually be reintroduced. If diarrhoea continues beyond 36–48 hours, a doctor should be consulted. Any signs of dehydration require urgent medical attention; such signs include drowsiness, lack of response, loose skin, persistent crying, glazed eyes and a dry mouth and tongue.... diarrhoea

Pseudomembrane

n. a false membrane, consisting of a layer of exudate on the surface of the skin or a mucous membrane. In diphtheria a pseudomembrane forms in the throat. In pseudomembranous colitis, a disease caused by *Clostridium difficile that usually follows antibiotic therapy, pseudomembranes develop in the colon, resulting in profuse diarrhoea.... pseudomembrane

Pseudomembranous Colitis

see Clostridium; pseudomembrane.... pseudomembranous colitis

Welch’s Bacillus

see Clostridium. [W. H. Welch (1850–1934), US pathologist]... welch’s bacillus



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