Clostridium

Clostridium botulinum

Clostridia (from Greek " spindle" ) are gram-positive, obligate anaerobic, spore -forming bacteria of the family of Clostridiaceae. The endospores are resistant to heat and can in boiling water for many hours, some at 110 ° C for about an hour to survive. Clostridia can actively move, with the exception of C. perfringens, with peritrichous flagella arranged.

The bacteria are ubiquitous ( ubiquitous ), especially in soils and in the digestive tract of higher organisms. You pass through dust and soil particles in food, where they can cause serious problems ( see below).

In the genus Clostridia are both pathogens ( pathogens ), as well as non-pathogenic species that are partly used in biotechnology. Among the pathogenic species are especially Clostridium botulinum ( botulism caused ) and Clostridium tetani ( causes tetanus ( lockjaw) ) call. Other types evoke gas fire, Bradsot, blackleg and Labmagenpararauschbrand.

Under the aspect of their preferred energy source clostridia can be divided into three major groups:

Primary fermentation products of saccharolytic Clostridium are butyric acid, acetone, butanol, carbon dioxide, and molecular hydrogen (H2).

• 2.1 clostridia Canned

• 3.1 Medically important clostridial species
• 3.2 virulence factors

Biotechnical importance

Production of organic solvents

Clostridium acetobutylicum is able to ferment sugar to the solvents acetone, 1-butanol, ethanol, and to the organic acids, acetic and butyric acid. The bacterium has been used on an industrial scale for the biotic production of said organic solvent until the mid 20th century. The first time it was described by Chaim Weizmann, the first president of Israel.

In addition, numerous other Clostridienarten for biotechnological production of various products are used or are being researched as potential producers, including ljungdahlii the useful for the synthesis gas fermentation Clostridium.

Clostridia in agriculture

Clostridia are widespread in soils. Saccharolytic clostridia (but not representative of the rest of Clostridiengruppen ) are capable of molecular nitrogen (N2 ) to reduce and thus to fix. They are therefore referred to as a diazotroph and are therefore natural fertilizer producers in the ground. Most active N2-fixing Clostridium pasteurianum the genus is in anoxic sediments.

In issue 10/2005 of dlz agricultural magazine before Aufschaukelung of clostridia in agricultural biogas plants (co - Vergäranlagen ) is warned. In such systems, manure from livestock waste and green waste from local authorities, business and industry are fermented anaerobically usually below 40 ° C. In this process, clostridia would find best propagation conditions. The author recommends plowed fermentation substrates and not applied to green areas. With the use of "effective microorganisms " is intended to also be reduced Aufschaukelung.

The NRW Chamber of Agriculture has warned regarding clostridia and biogas slurry in front of " scaremongering ". An increase of the often mentioned as problematic bacterium Clostridium perfringens had not been identified so far. In accordance with the Bavarian State Office for Agriculture, however, warned against the application of Fleischfresserkot and guano ( Vogeltrockenkot ) because in it one hundred thousand times more disease-causing bacteria from the Clostridium perfringens type than outside in the feces of herbivores. Here the number of bacteria is 100-10000 per 1 ml in the application of digestate from biogas plants to forage crops and pastures could possibly be a health hazard arise when these products are used.

Also, the risk of botulism, which starts from Clostridium botulinum, is to be restricted, eg poultry manure may only be used on farmland and in biogas plants in NRW, but not be spread on grassland and field grass areas.

Whether cheesemaking harmful clostridia with biogas plants can be linked, seems unlikely: The experience of two companies in NRW over 8 years even show a particularly low load.

Clostridia as a food spoiler or poisoner

• C. botulinum - Lebensmittelvergifter
• C. butyricum - Food spoiler
• C. estertheticum - Food spoiler, especially chilled meat
• C. pasteurianum - Food spoiler
• C. perfringens - Lebensmittelvergifter
• C. putrefaciens - Food spoiler
• C. sporogenes - Food spoiler
• C. tyrobutyricum - Food spoiler, especially in hard cheeses

Clostridia Canned

Clostridium endospores can survive with insufficient heating owing to their outstanding resistance to high temperatures in the sterilization of canned food. They germinate during storage of canned goods, and the clostridia multiply in it, because they do not need oxygen for their metabolism (they are obligate anaerobes ). Your metabolism leads to spoilage of canned goods: The Konservengut is decomposed, make it unpleasantly smelling and tasting acids formed gases carbon dioxide ( CO2) and molecular hydrogen ( H2) inflate the food cans (so called " camber ").

Medical importance

Medically important clostridial species

• Clostridium botulinum, the cause of botulism
• Clostridium chauvoei, causative agent of blackleg in cattle and sheep
• Clostridium difficile, the cause of antibiotic -induced intestinal inflammation, pseudomembranous colitis. In the patients entero - and cytotoxins are often detectable
• Clostridium gigas, agents of the German Bradsot (also a gas fire )
• Clostridium histolyticum, a rare and particularly dangerous gas blight pathogen
• Clostridium sordelii, another rare gas blight pathogen
• Clostridium perfringens, the classical gas gangrene pathogen which also causes food poisoning
• Clostridium piliforme, agent of Tyzzer 's Disease, which occurs particularly in rodents
• Clostridium septicum, causative agent of gas gangrene in humans and animals and Labmagenpararauschbrand the sheep
• Clostridium novyi, agents of the German Bradsot (also a gas fire )
• Clostridium tetani, causative agent of tetanus (tetanus )

Virulence factors

Various virulence factors come into vor.Clostridium Clostridia botulinum produces the botulinum toxin, which is inactivated after 30 minutes of heating at 80 ° C. The different types of hydrolytically cleave proteins containing the fusion with the synaptic membrane mediate ( synaptobrevin, syntaxin, SNAP -25). This in turn inhibits the release of acetylcholine from the synapse. Clostridium tetani produces tetanus toxin. It is released during the disintegration of the bacterial cell. Synaptobrevin is cleaved, and so the release of the inhibitory neurotransmitters glycine and GABA is inhibited (hence the name lockjaw). Clostridium perfringens produces among others the toxin alpha ( = lecithinase ) that destroys cell membranes, and it produces enterotoxins and pore-forming toxins. Clostridium difficile produce toxins A ( enterotoxin effects ) and B ( cytolytic activity).

The collagenases of Clostridium make an additional virulence factor. With the help of this enzyme is clostridia can by the breakdown of collagen spread particularly rapidly in the connective tissue of the host organism. Conversely collagenase is used from Clostridia in support of wound healing ( debridement ).