Mycoplasma ( from Ancient Greek μύκης mykes "mushroom" and πλάσμα plasma " the Molded " ) are very small, independently capable of reproduction bacteria of the class Mollicutes (from Latin mollis "soft" and cutis " skin ", " soft-skinned the "). In contrast to all other bacteria they lack a cell wall. They live aerobic to facultative anaerobic and are more diverse ( pleomorphic ), variable, vesicular shape.
Mycoplasmas are parasitic, intra-and extracellular viable bacteria that are the cause of many diseases in humans, animals and plants. The first type was isolated and described in 1898 from diseased cattle. The frequently observed mushroom-like filamentous forms were formative names for the genus Mycoplasma. In human medicine in 1962 succeeded in identification of each type Mycoplasma pneumoniae to a condition.
Kbp With a size of the genera Mycoplasma and Ureaplasma 580-1380 have the smallest genome of prokaryotes are capable of auto- replication with the exception of the deep-sea archaeon " Nanoarchaeum equitans " (~ 500 kbp). Your DNA genome usually has a relative low guanine - cytosine (GC) content and their cell membrane contains cholesterol, which is otherwise found only in eukaryotes.
The class of Mollicutes includes scientifically the six eubacterial genera Acholeplasma, Anaeroplasma, Asteroleplasma, Mycoplasma, Spiroplasma, and Ureaplasma.
However, members of the Mollicutes are often referred to by the more common term mycoplasma colloquial.
The phylogenetic relationship of these genera was determined by going back to Carl Woese analysis of 5S and 16S rRNA. A common feature of Mollicutes ( softskin ) and thus also the mycoplasma is the lack of a cell wall and the associated vulnerability to osmotic variations in the surrounding medium. Antibiotics (eg penicillins ) are on the cell wall fix virtually ineffective against them. Due to the small size of the mycoplasma they can be, in contrast to other bacteria, do not hold back through sterile filter with a nominal pore size of 0.22 microns. Molecular phylogenetic rRNA studies showed that the Mollicutes are not at the base of the bacterial phylogenetic tree, but rather by degenerative evolution from Gram- positive bacteria of the Lactobacillus group emerged with a low GC content of the DNA. In the course of this degenerative evolution, the Mollicutes have lost a significant part of their genetic information so that they are now one of the critters with the smallest known genome ( Mollicutes: 580-2300 kbp E. coli: 4.500 kbp Arabidopsis thaliana: 100,000 kbp, Homo sapiens: 3,400,000 kbp). Bacteria of the class Mollicutes not live as free bacteria, but are either dependent on a host cell or host organism.
As parasites or commensals they receive from the host organism essential metabolic components such as fatty acids, amino acids and precursors of nucleic acids. The possibility of reduction of the genome is attributed to the parasitic life of Mollicutes. For the growth of some representatives of Mollicutes also cholesterol is required, a component that is not normally found in bacteria and their synthetic precursors is also provided by the host cells.
Clinically significant mycoplasma
Mycoplasmas are parasitic living bacteria as the cause of many diseases in humans, animals and plants. In general, however, kill bacteria of the class Mollicutes their host not expire. Rather, they cause chronic infections, which indicates a good fit to the hosts, and thus represent a very successful type of parasitism.
In addition to the pathogenic properties of Mycoplasma infection of cell cultures with mycoplasma ( Mycoplasma mainly oral ) plays an important role. Since mycoplasmas lack a cell wall, they can be grown only on special nutrient media. Therefore, it has been established for the detection as a fast and cheap method, the standard polymerase chain reaction (PCR). This is not true for all mycoplasmas.
- Mycoplasma pneumoniae is the most important causative agent of so-called " atypical pneumonia ". But tracheobronchitis, pharyngitis, meningitis, ear infections and other diseases can be caused by Mycoplasma pneumoniae. In addition, the organism with disorders of the hematopoietic ( blood-forming ) system, the central nervous system, liver, and pancreas, as well as cardiovascular syndrome is associated.
- Mycoplasma genitalium in addition to Chlamydia trachomatis is a major causative agent of the so-called "non- gonococcal urethritis ," a non- Neisseria gonorrhoeae ( the so-called " Gonococci " ) caused urethral inflammation. In early 2008, a research group led by Craig Venter, it had succeeded in completely synthetically produce the first time the genetic material of a bacterium. Model for the reconstruction of the genome was Mycoplasma genitalium; the name of the synthetic Mycoplasma genitalium JCVI - replica is 1.0.
- Ureaplasma urealyticum colonized the lower female genital tract and is transmitted during pregnancy often from the mother to the child where they can be, inter alia, the cause of pneumonia or chronic infections of the central nervous system. Whether U. urealyticum also a causative agent of "non- gonococcal urethritis " is, is controversial.
- Mycoplasma fermentans plays, inter alia, may be a factor in causing the symptoms of HIV infection a role. In addition, there are reports of a possible involvement in the development of the symptoms of " chronic fatigue syndrome " (CFS ) and the possibly based on the CFS, " Gulf War Syndrome".
- Mycoplasma mycoides spp. mycoides SC ( small colony type) is causative agent of notifiable contagious bovine pleuropneumonia. It is the first known mycoplasma and was described in 1898 by Edmond Nocard and Émile Roux.
- Mycoplasma agalactiae is pathogen of contagious agalactia in small ruminants ( sheep, goats). Usually it comes to an unnoticed inflammation of the udder with milk yield decline, sometimes with joint or conjunctivitis (conjunctivitis).
- Mycoplasma bovis mastitis caused by decrease in milk yield in dairy cows and can also cause severe joint inflammation in calves in addition to pneumonia.
- Mycoplasma capricolum is the causative agent of contagious caprine pleuropneumonia.
- Mycoplasma conjunctivae is the etiological agent of Gämsblindheit.
- Mycoplasma felis, Mycoplasma may also gatae and Mycoplasma feliminutum are involved besides herpes and calicivirus as the causative agent in the cat flu complex.
- Mycoplasma gallisepticum is pathogens of respiratory diseases in poultry (CRD: chronic respiratory disease in chickens and infectious sinusitis in turkeys ). Frequently there is a mixed infection with other viral or bacterial pathogens (eg Haemophilus paragallinarum with Coryza contagiosa ).
- The so-called hämatotrophen mycoplasmas cause in cats (Mycoplasma haemofelis, Mycoplasma and Mycoplasma haemominutum turicensis, see Feline Infectious Anemia ), dogs (Mycoplasma haemocanis ) and swine ( Mycoplasma suis, see eperythrozoonosis the pigs) anemias. They were counted before the rickettsiae.
- Mycoplasma hyopneumoniae causes enzootic pneumonia of swine
- Mycoplasma hyorhinis and Mycoplasma hyosynoviae are the pathogens of Mykoplasmenarthritis and polyserositis of pigs
- Mycoplasma pulmonis is the causative agent of mycoplasmosis in rats, the most common disease of the upper respiratory tract held as a home or laboratory animal brown rats.
Specimen Collection and Transport
Due to a lack of bacterial cell wall, the mycoplasmas are very sensitive to drying out in samples and test materials. Samples of swabs must therefore be processed quickly or be placed in a transport medium. Mycoplasmas in tissue and sputum samples can be transported untreated. An interval of 24 to 48 hours from the sample collection and sample analysis can be bridged with cooling to 4 ° C. And freezing the sample at -70 ° C is possible.