Mycoplasma

Mycoplasma is a mollicute genus of bacteria that lack a cell wall around their cell membranes. This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis (like the beta-lactam antibiotics). They can be parasitic or saprotrophic. Several species are pathogenic in humans, including M. pneumoniae, which is an important cause of 'walking' pneumonia and other respiratory disorders, and M. genitalium, which is believed to be involved in pelvic inflammatory diseases. Mycoplasma species are the smallest bacterial cells yet discovered, can survive without oxygen, and come in various shapes. For example, M. genitalium is flask-shaped (about 300 x 600 nm), while M. pneumoniae is more elongated (about 100 x 1000 nm). Hundreds of mycoplasma species infect animals. The term mycoplasma, from the Greek μυκής, mykes (fungus) and πλάσμα, plasma (formed), was first used by Albert Bernhard Frank in 1889 to describe an altered state of plant cell cytoplasm resulting from infiltration by fungus-like microorganisms. Julian Nowak later proposed the genus name Mycoplasma for certain filamentous microorganisms imagined to have both cellular and acellular stages in their lifecycles, which could explain how they were visible with a microscope, but passed through filters impermeable to other bacteria. Later, the name for Mycoplasma was pleuropneumonia-like organisms (PPLO), broadly referring to organisms similar in colonial morphology and filterability to the causative agent (a mycoplasma) of contagious bovine pleuropneumonia. Other species of Mycoplasma other than those listed below have been recovered from humans, but are assumed to have been contracted from animals. These use humans as the primary host: Mycoplasma species have been isolated from women with bacterial vaginosis. M. genitalium is found in women with pelvic inflammatory disease. In addition, infection is associated with increased risk of cervicitis, preterm birth and spontaneous abortion, and infertility. Mycoplasma genitalium has developed resistance to some antibiotics. Mycoplasmae are associated with fetal respiratory distress syndrome, bronchopulmonary dysplasia, and intraventricular hemorrhage in preterm infants. Over 100 species have been included in the genus Mycoplasma. Microbes of the class Mollicutes, to which Mycoplasma belongs, are parasites or commensals of humans, animals, and plants. The genus Mycoplasma uses vertebrate and arthropod hosts.Dietary nitrogen availability has been shown to alter codon bias and genome evolution in Mycoplasma and Phytoplasma.