Clostridium
Clostridium is a genus of anaerobic bacteria. These are gram-positive bacilli, parasites and saprophytes. Some of these genera sporulate and are motile, generally due to the presence of peritrichous flagella. They take the shape of a match, drumstick or spinning spindle, hence their Greek name "klostro", meaning spinning spindle. The most important species are Clostridium botulinum, which causes botulism, Clostridium novyi, Clostridium septicum, Clostridium perfringens, which cause gas gangrene and Clostridium tetani, from tetanus.
In 2016, the species C. difficile and C. mangenotii were reclassified into the new genus Clostridioides.
It has been suggested that phylogenetically it is a polyphyletic genus that would divide into several different and not closely related genera.
Features
Genre is defined by four characteristics:
- Presence of endosporas
- Strict anaerobic metabolism
- Inability to reduce sulphates to sulphites
- Cellular gram positive
The Clostridium are organisms that are observed solitary, in pairs or at most in short chains. They are mobile because they present peritrichous flagella -with the exception of C. perfringens. Some species produce a capsule and form spores with spherical or oval aspects, located in the center of the bacillus or at a subterminal end and resistant to heat. Despite being obligate anaerobic bacteria, not all have the same sensitivity to oxygen. C. tetani, for example, requires full anaerobiosis and C. perfringes tends to be less demanding. They grow at a temperature of 37 °C and at a pH between 7 and 7.4, so they are easily inactivated at acidic or basic pH, such as stomach acid, cleaners and disinfectants such as chlorine and even the pH of organic acids. found in lemon juice, for example. They are sugar fermenters, an aspect that is useful in the differentiation of species.
They have somatic and flagellar antigens that allow them to be divided into types and subtypes. They produce exotoxins with a necrotizing, hemolytic and potentially lethal effect. Toxins are named with letters, for example, necrotizing toxin is named with the letter C and enteritis in animals is caused by toxins B, D and E.
Habitat
Not all species are pathogenic, some are part of the normal intestinal flora. Clostridium species are widely distributed in the environment, inhabiting the gastrointestinal tract of both humans and animals. Despite the interest in relation to Clostridium for the reason that these organisms are related to diarrhoea.
Pathology
The Clostridium include common and naturally occurring bacteria, as well as important pathogens. There are six main species responsible for human disease:
- C. botulinum (of the word botulus, sausage) is an organism that produces a food toxin that causes botulism, a potentially lethal acute neurological disorder. See also: Toxin botulinum
- C. perfringens (called perfringens, literally "going through" because it is associated with invasive necrosis) causes a wide range of symptoms, from food poisoning to gaseous gangrene. It is also a cause of enterotoxemia, often hemorrhagic in rams (especially lambs), bulls, sheep and goats.
- C. tetani (de) tetani, which means stiffness) is the cause of tetanus (trism), characterized by excessive muscle stiffness.
- C. septicum (his name comes from the word septicum, translated as "putrefactor") is one of the etiological agents of septicemia and represents a high mortality.
- C. sordellii, named in honor of the bacteriologist Alfredo Sordelli who isolated him for the first time. It can be part of the female genital flora. He's been involved in cases of toxic shock after delivery.
| Clinical table | Ethological agent |
|---|---|
| Tetanus | C. tetani |
| Botulism | C. botulinum, C. baratii, C.butyricum |
| Gangrena gaseous | C. perfringens, C. novyi, C. septicum, C. histolyticum |
| Diarrhea | C. perfringens |
| Colitis | C. perfringens |
Commercial uses
- C. thermocellum can generate ethanol from certain wastes, making it a possible candidate in the use and production of ethanol. By not having oxygen requirements and by being thermophilic, cooling costs are reduced
- C. acetobutylicumalso known as the Weizmannwhich was first used by Jaim Weizmann in the production of acetone and biobutanol from starch in 1916 in the production of powder and TNT.
- C. ljungdahlii, recently discovered in commercial chicken wastes, can produce ethanol from single-carbon sources, including Syngas, a mixture of carbon dioxide and hydrogen that can be generated from the partial combustion of both biomass and fossil fuel. The use of these bacteria to produce ethanol is already a project in various energy plants.
Due to the danger posed by Clostridium botulinum and other pathogens, the only safe method of canning most foods is under conditions of high pressure and temperature, typically around 116-121° c.
Gallery
Clostridium botulinum
Clostridium perfringens
