Mycoplasmataceae

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Mycoplasmataceae
Systematics
Classification : Creature
Domain : Bacteria (bacteria)
Department : Tenerife
Class : Mollicutes
Order : Mycoplasmatales
Family : Mycoplasmataceae
Scientific name of the  order
Mycoplasmatales
Friends in 1955
Scientific name of the  family
Mycoplasmataceae
Friends in 1955

The Mycoplasmataceae are the only bacterial family of the order Mycoplasmatales . Most species are parasites and often pathogens that are dangerous to humans and animals .

They belong to the class of Mollicutes and have (like almost all representatives of the Mollicutes) no cell wall, Murein is not available. Their genome is very small, which makes them particularly interesting for genetics . Mycoplasma genitalium with 580 kbp was completely sequenced.

The colloquial term mycoplasma (or also written with "c": mycoplasma) mostly refers to the class Mollicutes, not to the family Mycoplasmataceae or the species Mycoplasma specifically. This article is also based on this, the term mycoplasma here stands for all representatives of the Mollicutes.

There are two genera in the family: Mycoplasma and Ureaplasma .

History

The first species was isolated in 1898 from cattle suffering from pleuropneumonia (lung disease). At that time the bacterium was still referred to as "pleuropneumoniae-like organisms" (PPLO). In veterinary medicine, Mycoplasma has long been known as a pathogen, the first clear classifications to diseases in humans followed only later. The first species, Mycoplasma hominis (responsible for urinary tract infections), was not isolated from humans until 1937. Monroe Eaton recognized the causative agent of atypical pneumonia (atypical pneumonia ) in the 1940s , later this bacterium was named Mycoplasma pneumoniae . The Mycoplasmataceae family was officially introduced by Freundt in 1955. Synonyms which also reflect the history of the taxonomy of the family are "Borrelomycetaceae" by Turner in 1935, "Parasitaceae" Sabin 1941 and "Pleuropneumoniaceae" Tulasne and Brisou 1955 .

features

The two genera colonize humans and animals as parasites. Other genera of the Mollicutes, such as Spiroplasma , are also found in insects and plants, e.g. B. S. apis in bees and some plant species. Most species tolerate oxygen, but do not necessarily need it (facultative anaerobic ). Some types, such as B. Mycoplasma hyorhinis cannot live in the complete absence of oxygen, they are obligatory aerobic . The urease test is positive for Ureaplasma ; in contrast to Mycoplasma , Ureaplasma is able to break down urea . They are intracellular germs.

The mycoplasmas can usually change their cell shape, they are pleomorphic . The most common cell shape is coccoid. B. fungus-like filamentous forms observed (hence the name Mycoplasma). Some types of ureaplasma form short chains or cluster-shaped clusters.

As already mentioned, mycoplasma lacks cell walls. The genus Erysipelothrix is an exception . Although it has a cell wall, it was made due to the similarities of the DNA to the Mollicutes. For this purpose the family Erysipelotrichaceae Verbarg et al. Created in 2004 , the position within the class is still unclear (“ Incertae sedis ”).

The Mycoplasmataceae do not have flagella , pili or fimbriae . Species of Mycoplasma and Ureaplasma are therefore usually immobile. However, some species are able to slide around on liquid surfaces. 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 species are necessarily pathogenic and often belong to the natural bacterial flora . They are therefore not always pathogenic or only under special circumstances. This applies e.g. B. for Mycoplasma hominis and Ureaplasma urealyticum . These species also colonize the urogenital tract without causing disease (facultative pathogenic). Mycoplasma orale and M. salivarium often occur in the oral cavity and are harmless commensals here .

Other non-pathogenic (non-pathogenic) species in people who are not immunocompromised:

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

Due to the lack of the cell wall, Mycoplasma and Ureaplasma are resistant to antibiotics that attack the cell wall or inhibit murein synthesis, e.g. B. penicillin .

The infectious diseases caused are also referred to as mycoplasmoses .

Examples in human medicine

Some pathogenic species:

  • Mycoplasma pneumoniae causes atypical pneumonia (inflammation of the lungs).
  • Mycoplasma hominis , like Ureaplasma urealyticum, is a causative agent of unspecific infections of the urogenital tract .

Examples in veterinary medicine

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

Systematics

Genera and some species (incomplete):

The genus name Haemobartonella is a synonym and no longer relevant, the respective species were assigned to Mycoplasma . The genus Eperythrozoon with the only species Eperythrozoon parvum is under discussion.

swell

  1. ↑ Systematics according to JP Euzéby: List of Prokaryotic Names with Standing in Nomenclature - as of August 24, 2018
  2. ↑ LPSN ( Memento of the original from October 21, 2018 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.bacterio.net
  3. ↑ LPSN

literature

  • Shmuel Razin: The Genus Mycoplasma and Related Genera (Class Mollicutes) In: The Prokaryotes, A Handbook of the Biology of Bacteria . 7 volumes, 3rd edition, Springer-Verlag, New York et al. O., 2006, ISBN 0-387-30740-0 . Volume 4: Bacteria: Firmicutes, Cyanobacteria ISBN 978-0-387-25494-4
  • Shmuel Razin and Richard Herrmann: Molecular Biology and Pathogenicity of Mycoplasmas 1st edition, Springer Verlag, 2002 ISBN 0-306-47287-2
  • Köhler, Werner (Ed.) Medical Microbiology , 8th edition, Munich / Jena 2001 ISBN 978-3-437-41640-8
  • Michael T. Madigan, John M. Martinko, Jack Parker: Brock - Microbiology . 11th edition. Pearson Studium, Munich 2006, ISBN 3-8274-0566-1