The Mycoplasmataceae are the only family of the order Mycoplasmatales bacteria. Most species are parasitic and often for humans and animals dangerous pathogens ( pathogen ).

They belong to the class of Mollicutes and have (as almost all representatives of Mollicutes ) no cell wall murein does not exist. Although the Gram test is based on the structure of the cell wall that does not respond favorably, they are a result of DNA analysis provided the gram-positive bacteria with low GC content in DNA ( Firmicutes ). Their genome is very small, which makes them particularly interesting for the genetics. Mycoplasma genitalium was kbp with 580 fully sequenced.

The colloquial term mycoplasma (or "c" wrote: mycoplasmas ) usually refers to the class Mollicutes, not on the family Mycoplasmataceae or the species Mycoplasma special. After this is also directed this Article, the term mycoplasma is here for all the representatives of Mollicutes.

In the family two genera are represented: Mycoplasma and Ureaplasma.


The first type was founded in 1898 by at pleuropneumonia ( CBPP ) infected cattle isolated. At that time, the bacterium still as " pleuropneumoniae -like organisms " ( PPLO ) was called. In veterinary medicine, Mycoplasma means it is already longer than pathogens known first unambiguous classifications to diseases in humans followed later. The first type, Mycoplasma hominis (responsible for urinary tract infections), was isolated only in the year 1937 by the people. Monroe Eaton recognized in the 40s of last century, the causative agent of atypical pneumonia (atypical pneumonia), later this bacterium Mycoplasma pneumoniae was called. The Mycoplasmataceae family was officially introduced by Boyfriend in 1955. Synonyms which are reflected the taxonomic history of the family " Borrelomycetaceae " by Turner in 1935, " Parasitaceae " Sabin 1941 and " Pleuropneumoniaceae " Tulasne and Brisou 1955.


The two species colonize as parasites exclusively humans and animals. Other genera of mollicutes, such as Spiroplasma are also found in insects and plants, eg S. apis in bees and some plant species. Most species tolerate oxygen, but not absolutely need it ( facultative anaerobes ). Some species, such as Mycoplasma hyorhinis can not live under complete exclusion of oxygen, they are obligately aerobic. The urease test is positive for Ureaplasma, Mycoplasma unlike Ureaplasma is able to reduce the urea. You are intracellular pathogens.

The mycoplasma can usually change their cell shape, they are pleomorphic. The cell shape is most common coccoid, next to eg mushroom-like filamentous forms were observed (hence the name Mycoplasma ). Types of Ureaplasma partially form short chains or grape-like clusters.

As already mentioned lack cell walls in mycoplasmas. An exception is the class Erysipelothrix. Although it has a cell wall, but was found to Mollicutes due to similarities of the DNA. This family Erysipelotrichaceae Verbarg et al. Created in 2004, the position within the class is still unclear ( " Incertae sedis ").

The Mycoplasmataceae flagella, pili and fimbriae are absent. Species of Mycoplasma and Ureaplasma are thus not movable in the rule. However, some species are able to move on liquid surfaces sliding. These include Mycoplasma pneumoniae, M. genitalium, M. pulmonis, M. gallisepticum and M. mobile.

Clinically important species

The parasitic mycoplasmas usually cause chronic infections, the host is not killed. Furthermore, not all types obligate pathogenic and are often among the natural bacterial flora. Thus, they are not always, or only under special circumstances produce illness. This applies eg for urealyticum Mycoplasma hominis and Ureaplasma. These species also colonize the urogenital tract without causing disease ( pathogenic optional ). Mycoplasma oral and M. salivarium often occur in the oral cavity and here are harmless commensals.

Other non-pathogenic in non- immunocompromised people ( not disease causing) types:

  • Most commonly found in the oropharynx ( oral cavity ) found: Mycoplasma salivarium, M oral, buccal, M., M. and M. faucium lipophilum.
  • In the urogenital tract Mycoplasma spermatophylum and M. primatum.

By the absence of the cell wall are Mycoplasma and Ureaplasma resistant to the cell wall acting or murein synthesis inhibiting antibiotics such as penicillin.

The infection diseases we also speak of the mycoplasmosis.

Examples in human medicine

Some pathogenic species:

  • Mycoplasma pneumoniae causes atypical pneumonia (lung inflammation ).
  • Mycoplasma hominis, Ureaplasma urealyticum, among others, as well as a cause of non-specific infections of the urogenital tract.

Examples in veterinary medicine

  • Mycoplasma californicum and Mycoplasma conjunctivae: The Gämsblindheit (English: infectious keratoconjunctivitis IKC ) at, eg, goat, sheep, ibex and goats.
  • Mycoplasma mycoides ssp. mycoides: contagious bovine pleuropneumonia ( Contagious bovine pleuropneumonia engl. )
  • Ureaplasma diversum: cause of metritis and abortion in cattle.

For other diseases caused by Mycoplasma and Ureaplasma urealyticum see there.


Some genera and species ( incomplete):

  • Mycoplasma Nowak 1929 Mycoplasma bovirhinis Leach 1967
  • Mycoplasma buccal Freundt et al. 1974
  • Mycoplasma gallinarum Freundt 1955
  • Mycoplasma lipofaciens Bradbury et al. 1983
  • Mycoplasma ovis ( Neitz et al. 1934) Neimark et al. 2004
  • Ureaplasma Shepard et al. 1974 Ureaplasma gallorale Koshimizu et al. 1987
  • Ureaplasma urealyticum Shepard et al. 1974 ( Approved Lists 1980) emend. Robertson et al. 2002

The genus name is a synonym Haemobartonella and out of date, the species were asked to Mycoplasma.