Clostridium tetani
Clostridium tetani with characteristic 'tennis racket' appearance.
Scientific classification
Kingdom: Bacteria Division: Firmicutes Class: Clostridia Order: Clostridiales Family: Clostridiaceae Genus: Clostridium Species: C. tetani
Binomial name
Clostridium tetani Flügge, 1886

Clostridium tetani is a rod-shaped, anaerobic bacterium of the genus Clostridium. Like other Clostridium species, it is Gram-positive, and its appearance on a gram stain resembles tennis rackets or drumsticks.^[1] C. tetani is found as spores in soil or as parasites in the gastrointestinal tract of animals. C. tetani produces a potent biological toxin, tetanospasmin, and is the causative agent of tetanus. Image File history File links Clostridium_tetani_01. ... For other uses, see Scientific classification (disambiguation). ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Classes Bacilli Clostridia Mollicutes The Firmicutes are a division of bacteria, most of which have Gram-positive cell wall structure. ... Orders The Clostridia are a class of Firmicutes, including Clostridium and other similar genera. ... Genera Acetanaerobacterium Acetivibrio Acidaminobacter Alkaliphilus Anaerobacter Anaerotruncus Anoxynatronum Bryantella Caldanaerocella Caloramator Caloranaerobacter Caminicella Candidatus Arthromitus Clostridium Coprobacillus Dorea Ethanologenbacterium Faecalibacterium Garciella Guggenheimella Hespellia Linmingia Natronincola Oxobacter Parasporobacterium Sarcina Soehngenia Sporobacter Subdoligranulum Tepidibacter Tepidimicrobium Thermobrachium Thermohalobacter Tindallia The Clostridiaceae are a family of the Clostridia, and contains the Clostridium genus. ... Species Clostridium acetobutylicum Clostridium aerotolerans Clostridium botulinum Clostridium colicanis Clostridium difficile Clostridium formicaceticum Clostridium novyi Clostridium perfringens Clostridium sordelli Clostridium tetani Clostridium piliforme Clostridium tyrobutyricum etc. ... This article does not cite any references or sources. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Species Clostridium acetobutylicum Clostridium aerotolerans Clostridium botulinum Clostridium colicanis Clostridium difficile Clostridium formicaceticum Clostridium novyi Clostridium perfringens Clostridium sordelli Clostridium tetani Clostridium piliforme Clostridium tyrobutyricum etc. ... Gram-positive bacteria are those that are stained dark blue or violet by gram staining, in contrast to gram-negative bacteria, which are not affected by the stain. ... Gram staining is a method for staining samples of bacteria that differentiates between the two main types of bacterial cell wall. ... Squash racquet and ball Racquetball racquet and ball Tennis racquets and balls A racquet (or racket) is a sports implement consisting of a handled frame with an open hoop across which a network of cord is stretched. ... An endospore is a dormant, tough, non-reproductive structure produced by a small number of bacteria from the Firmicute family. ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... Gut redirects here. ... Structure of tetanospasmin Mechanism of action of tetanospasmin Tetanospasmin is the neurotoxin produced by the vegetative spore of Clostridium tetani in anaerobic conditions, causing tetanus. ... Tetanus is a medical condition that is characterized by a prolonged contraction of skeletal muscle fibers. ...

History

Tetanus was well known to ancient peoples, who recognized the relationship between wounds and fatal muscle spasms. In 1884, Arthur Nicolaier isolated the strychnine-like toxin of tetanus from free-living, anaerobic soil bacteria. The etiology of the disease was further elucidated in 1884 Antonio Carle and Giorgio Rattone, who demonstrated the transmissibility of tetanus for the first time. They produced tetanus in rabbits by injecting their sciatic nerve with pus from a fatal human tetanus case in that same year. In 1889, C. tetani was isolated from a human victim, by Kitasato Shibasaburo, who later showed that the organism could produce disease when injected into animals, and that the toxin could be neutralized by specific antibodies. In 1897, Edmond Nocard showed that tetanus antitoxin induced passive immunity in humans, and could be used for prophylaxis and treatment. Tetanus toxoid vaccine was developed by P. Descombey in 1924, and was widely used to prevent tetanus induced by battle wounds during World War II.^[2] Tetanus is a medical condition that is characterized by a prolonged contraction of skeletal muscle fibers. ... Strychnine (pronounced (British, U.S.), or (U.S.)) is a very toxic (LD50 = 10 mg approx. ... Shibasaburo Kitasato (北里 柴三郎) (1852-1931) was a Japanese physician and bacteriologist. ... Wikipedia does not yet have an article with this exact name. ... Edmond Nocard (1850-1903) was a French veterinarian and microbiologist, born in Provins (Seine-et-Marne, France). ... Categories: Possible copyright violations ... Prophylaxis refers to any medical or public health procedure whose purpose is to prevent, rather than treat or cure, disease. ... A vaccine is an antigenic preparation used to establish immunity to a disease. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

Characteristics

C. tetani is a rod-shaped, obligate anaerobe which stains Gram positive in fresh cultures; established cultures may stain Gram negative.^[1] During vegetative growth, the organism cannot survive in the presence of oxygen, is sensitive to heat and has flagella which provide limited mobility. As the bacterium matures, it develops a terminal spore, which gives the organism its characteristic appearance. C. tetani spores are extremely hardy, and are resistant to heat and most antiseptics.^[3] The spores are distributed widely in manure-treated soils, and can also be found on human skin and in contaminated heroin.^[2] Gram-positive Bacillus anthracis bacteria (purple rods) in cerebrospinal fluid sample. ... Gram-negative Pseudomonas aeruginosa bacteria (pink-red rods). ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... For the insect anatomical structure, see Antenna (biology). ... An endospore is a dormant, tough, non-reproductive structure produced by a small number of bacteria from the Firmicute family. ... An antiseptic is a substance that kills or prevents the growth of bacteria on the external surfaces of the body. ... Animal manure is often a mixture of animals feces and bedding straw, as in this example from a stable. ... For other uses, see Heroin (disambiguation). ...

Toxicity

C. tetani usually enters a host through a wound to the skin, it then replicates and germinates spores. Once an infection is established, C. tetani produces two exotoxins, tetanolysin and tetanospasmin. Eleven strains of C. tetani have been identified, which differ primarily in flagellar antigens and in its ability to produce tetanospasmin. The genes that produce toxin are encoded on a plasmid which is present in all toxigenic strains, and all strains that are capable of producing toxin produce identical toxins.^[4] Tetanolysin is a toxin produced by Clostridium tetani bacteria. ... Structure of tetanospasmin Mechanism of action of tetanospasmin Tetanospasmin is the neurotoxin produced by the vegetative spore of Clostridium tetani in anaerobic conditions, causing tetanus. ... An antigen or immunogen is a molecule that stimulates an immune response. ... Figure 1: Illustration of a bacterium with plasmids enclosed showing chromosomal DNA and plasmids. ...

Tetanolysin serves no known function to C. tetani, and the reason the bacteria produce it is not known with certainty. Tetanospasmin is a neurotoxin and causes the clinical manifestations of tetanus. Tetanus toxin is generated in living bacteria, and is released when the bacteria lyses, such as during spore germination or during vegetative growth. A minimal amount of spore germination and vegetative cell growth are required for toxin production.^[4] A neurotoxin is a toxin that acts specifically on nerve cells – neurons – usually by interacting with membrane proteins such as ion channels. ...

On the basis of weight, tetanospasmin is one of the most potent toxins known. The estimated minimum human lethal dose is 2.5 nanograms per kilogram of body weight, or 175 nanograms in a 70 kg (154 lb) human.^[2] The only toxins more lethal to humans are botulinum toxin, produced by Clostridium botulinum and the exotoxin produced by Corynebacterium diphtheriae, the causative agent of diphtheria. The nanogram is an SI unit of mass (symbol ng) defined as: 1 ng = 1 × 10-12 kilogram (1 × 10-9 gram) A nanogram is one billionth (1/1,000,000,000) of a gram. ... “Kg” redirects here. ... Botulinum toxin is a neurotoxin protein produced by the bacterium Clostridium botulinum. ... Binomial name van Ermengem, 1896 Clostridium botulinum is a bacterium that produces the toxin botulin, the causative agent in botulism. ... Diphtheria toxin is an exotoxin secreted by Corynebacterium diphtheriae, the pathogen bacterium that causes diphtheria. ... Binomial name Kruse, 1886 Corynebacterium diphtheriae is a pathogenic bacterium that causes diphtheria. ...

Tetanospasmin is a zinc-dependent metalloproteinase, that is similar in structure to botulinum toxin, but each toxin produces quite different effects. C. tetani synthesizes tetanospasmin as a single 150kDa polypeptide progenitor toxin, that is then cleaved by a protease into two fragments; fragment A (a 50kDa "light chain") and fragment B (a 100 kDa heavy chain) which remain connected via a disulfide bridge. Cleavage of the progenitor toxin into A and B fragments can also be induced artificially with trypsin.^[4] General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... The metalloendopeptidases (also called metalloproteinases or metalloproteases) are a class of enzymes from the group of endopeptidases. ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... Peptides are the family of molecules formed from the linking, in a defined order, of various amino acids. ... Proteases (proteinases, peptidases, or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. ...

Toxin Action

Tetanospasmin is distributed in the blood and lymphatic system of the host. The toxin acts at several sites within the central nervous system, including peripheral nerve terminals, the spinal cord, and brain, and within the sympathetic nervous system. The toxin is taken up into within the nerve axon and transported across synaptic junctions, until it reaches the central nervous system, where it is rapidly fixed to gangliosides at the presynaptic junctions of inhibitory motor nerve endings.^[2] A diagram showing the CNS: 1. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system--to serve the limbs and organs, for example. ... The Spinal cord nested in the vertebral column. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... The Sympathetic Nervous System (SNS) is a branch of the autonomic nervous system. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Ganglioside is a compound composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (AKA n-acetylneuraminic acid) linked on the sugar chain. ...

The clinical manifestations of tetanus are caused when tetanus toxin blocks inhibitory impulses, by interfering with the release of neurotransmitters, including glycine and gamma-aminobutyric acid. This leads to unopposed muscle contraction and spasm. Seizures may occur, and the autonomic nervous system may also be affected. Tetanospasmin appears to prevent the release of neurotransmitters by selectively cleaving a component of synaptic vesicles called synaptobrevin II.^[4] Chemical structure of D-aspartic acid, a common amino acid neurotransmitter. ... For the plant, see Glycine (plant). ... Gamma-aminobutyric acid (usually abbreviated to GABA) is an inhibitory neurotransmitter found in the nervous systems of widely divergent species. ... This article is about the medical condition. ... This article or section is in need of attention from an expert on the subject. ... Three different views of the high resolution structure of a truncated neuronal SNARE complex. ...

It should be noted that the organism itself has no access to the nervous system, and yet tetanospasmin is directed toward the nervous system. The reason why this occurs, is still a subject of controversy. It's fairly known that toxins are by-products synthesized during bacterial growth, and their targets are determined by the presence or absence of specific receptors on human cells to which they can bind and exert their effect. This only explains why the tetanus toxin acts on the nervous system, but why it reaches a place to which the organism itself has no access may be an anomaly of nature. Structure of tetanospasmin Mechanism of action of tetanospasmin Tetanospasmin is the neurotoxin produced by the vegetative spore of Clostridium tetani in anaerobic conditions, causing tetanus. ... For other uses, see Toxin (disambiguation). ...

Treatment

Main article: Tetanus

When a tetanus infection becomes established, treatment usually focuses on controlling muscle spasms, stopping toxin production, and neutralizing the effects of the toxin. Treatment includes administration of tetanus immune globulin (TIG), which comprises antibodies that inhibit tetanus toxin (also known as tetanus antitoxins), by binding to and removing unbound tetanus toxin from the body. Binding of the toxin to the nerve endings appears to be an irreversible event, and TIG is ineffective at removing bound toxin. Recovery of affected nerves requires the sprouting of a new axon terminal.^[4] Large doses of antibiotic drugs (such as metronidazole or intramuscular penicillin G) are also given once tetanus infection is suspected, to halt toxin production. Tetanus is a medical condition that is characterized by a prolonged contraction of skeletal muscle fibers. ... An antitoxin is an antibody with the ability to neutralize a specific toxin. ... Metronidazole (INN) (IPA: ) is a nitroimidazole anti-infective drug used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. ... Intramuscular injection is an injection of a substance directly into a muscle. ... For the Japanese rock band, see Penicillin (band). ...

Prevention of tetanus includes vaccination, and cleaning the primary wound. Prophylaxis is effective, in the form of a tetanus toxoid vaccine, which is given with or without passive immunization with tetanus immune globulin. Very few cases of tetanus have occurred in individuals with up-to-date tetanus vaccinations. DTP vaccine (diphtheria-pertussis-tetanus) in North America, is given at 2, 4, 6, and 15–18 months of age, followed by a booster before entry to school (4-6 years). This regimen provides protection from tetanus for about 10 years, and every 10 years, thereafter a booster shot of tetanus vaccine is recommended.^[2] A toxoid is a bacterial toxin whose toxicity has been weakened or suppressed either by chemical (formalin) or heat treatment, while other properties, typically immunogenicity, are maintained. ... Passive immunity occurs when high levels of human (or horse) antibodies specific for a pathogen or toxin are transferred to non-immune individuals. ... It has been suggested that this article or section be merged into DPT vaccine. ...

Tetanus is not contagious from person to person, and is the only vaccine-preventable disease that is infectious but not contagious. A C. tetani infection does not result in tetanus immunity, and tetanus vaccination should be given as soon as the patient has stabilized.^[2] This false-colored electron micrograph shows a malaria sporozoite migrating through the midgut epithelia. ... Immunity is a medical term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. ...

References

Further reading

• Clinical Microbiology, ISBN 0-940780-49-6

External links

• Pathema-Clostridium Resource