Ureaplasma

Abstract

U.re.a.plas'ma. N.L. fem. n. urea urea; Gr. neut. n. plasma anything formed or moulded, image, figure; N.L. neut. n. Ureaplasma urea form. Tenericutes / Mollicutes / Mycoplasmatales / Mycoplasmataceae / Ureaplasma Bacteria in the genus Ureaplasma are small (350–500 nm in diameter) coccoid cells, devoid of a cell wall, that form exceptionally tiny (<0.2 mm) colonies on solid media. Like the closely‐related genus Mycoplasma , ureaplasmas have small (0.75–1.2 Mb) A+T‐rich genomes, use the codon UGA to encode tryptophan, and are nutritionally fastidious, but unlike mycoplasmas they hydrolyze urea rather than glucose or arginine for ATP synthesis. DNA–DNA hybridizations and serotyping involving a family of phase‐variable surface lipoproteins called multiple‐banded antigens have been important in developing the species concept for this genus. In nature all species are obligate commensals or opportunistic pathogens of vertebrate hosts. Based on the most recent comparative genome analyses, a consensus is emerging that the strains associated with humans, currently recognized as biovars of either Ureaplasma urealyticum or Ureaplasma parvum , probably exist collectively as quasi‐species rather than as stable serovars in their native environment. DNA G + C content (mol%) : 25–32 (Bd, T m , complete genome sequences). Type species : Ureaplasma urealyticum Shepard, Lunceford, Ford, Purcell, Taylor‐Robinson, Razin and Black 1974, 167 AL emend. Robertson, Stemke, Davis, Harasawa, Thirkell, Kong, Shepard and Ford 2002, 593.