| Mollicutes | |
|---|---|
Scientific classification 
| |
| Domain: | Bacteria |
| Phylum: | Mycoplasmatota |
| Class: | Mollicutes Edward and Freundt 1967[1] |
| Orders | |
|
Acholeplasmatales | |
| Synonyms | |
| |
Mollicutes is a class of bacteria[2] distinguished by the absence of a cell wall. The word "Mollicutes" is derived from the Latin mollis (meaning "soft" or "pliable"), and cutis (meaning "skin"). Individuals are very small, typically only 0.2–0.3 μm (200–300 nm) in size and have a very small genome size. They vary in form, although most have sterols that make the cell membrane somewhat more rigid. Many are able to move about through gliding, but members of the genus Spiroplasma are helical and move by twisting. The best-known genus in the Mollicutes is Mycoplasma. Colonies show the typical "fried-egg" appearance.
Mollicutes are parasites of various animals and plants, living on or in the host's cells. Many cause diseases in humans, attaching to cells in the respiratory or urogenital tracts, particularly species of Mycoplasma and Ureaplasma. Phytoplasma and Spiroplasma are plant pathogens associated with insect vectors.
Whereas formerly the trivial name "mycoplasma" (plural: "mycoplasmas") has commonly denoted any member of the class Mollicutes, it now in scientific classification refers exclusively to a member of the genus Mycoplasma.