- The mycoplasma are a very large group of bacteria. There are more than 70 types. Mycoplasma hominis and Mycoplasma pneumoniae are among the dozen types of mycoplasma that occur in humans. Mycoplasma hominis is a common inhabitant of the vagina and can cause infections of the female and male genital tracts. Mycoplasma pneumoniae can infect the upper respiratory tract and the lungs. It is a major cause of respiratory infection in children of school age and young adults. It is also a common cause of pneumonia in persons with HIV. Certain antibiotics including tetracycline and erythromycin are frequently used to treat infection with Mycoplasma hominis or Mycoplasma pneumoniae. Mycoplasma are very simple one-celled organisms without an outer membrane. They penetrate and infect individual cells.
* * *A genus of aerobic to facultatively anaerobic bacteria (family Mycoplasmataceae) containing Gram-negative cells that do not possess a true cell wall but are bounded by a three-layered membrane; they do not revert to bacteria containing cell walls or cell wall fragments. The minimal reproductive units of these organisms are 0.2–0.3 μm in diameter. The cells are pleomorphic, and in liquid media appear as coccoid bodies, rings, or filaments. Colonies of most species consist of a central core, growing down into the medium, surrounded by superficial peripheral growth. They require sterol for growth. They also require enrichment with serum or ascitic fluid. These organisms are found in humans and other animals and can be pathogenic. The type species is M. mycoides. SYN: Asterococcus. [myco- + G. plasma, something formed (plasm)]- M. buccale a species which is an infrequent parasitic inhabitant of the human oropharynx; it is the predominant m. in the oropharynx of nonhuman primates.- M. faucium a bacterial species that is a rare member of the normal flora of the human oropharynx; it is occasionally found in the oropharynx of nonhuman primates.- M. fermentans a bacterial species found in ulcerative genital lesions associated with fusiform bacteria and spirilla and also on the apparently normal genital mucosa of humans.- M. genitalium a bacterial species that may be a causative agent of urethritis; cross-reacts immunologically with M. pneumoniae; can cause serious infections involving the respiratory tract, heart, bloodstream, central nervous system, and prosthetic valves and joints.- M. hominis a bacterial species that is the causative agent of pelvic inflammatory disease and other genitourinary tract infections; can also cause chorioamnionitis and postpartum fever; can be an oropharyngeal commensal and has caused nosocomial wound infections.- M. laidlawii SYN: Acholeplasma laidlawii.- M. orale a bacterial species of M. associated with the buccal and pharyngeal cavities of humans and animals.- M. pneumoniae a bacterial species causing otitis and upper and lower respiratory tract disease including primary atypical pneumonia in human beings. SYN: Eaton agent.
* * *my·co·plas·ma .mī-kō-'plaz-mə n1) cap the type genus of the family Mycoplasmataceae containing minute pleomorphic gram-negative chiefly nonmotile bacteria that are mostly parasitic usu. in mammals see PLEUROPNEUMONIA (2)2) pl -mas also -ma·ta -mət-ə any bacterium of the genus Mycoplasma or of the family Mycoplasmataceae called also pleuropneumonia-like organism, PPLOmy·co·plas·mal -məl adj
* * *n.one of a group of minute nonmotile microorganisms that lack a rigid cell wall and hence display a variety of forms. They are regarded by most authorities as primitive bacteria. The group includes some species that cause severe respiratory disease in cattle, sheep, and goats; one of these, Mycoplasma pneumoniae, causes atypical pneumonia in humans. The group also includes the pleuropneumonia-like organisms (PPLO).
* * *My·co·plas·ma (miґko-plaz″mə) [myco- + Gr. plasma anything formed or molded] a genus of bacteria of the family Mycoplasmataceae, made up of round, highly pleomorphic, gram-negative cells that are bounded by a single triple-layered membrane and lack a true cell wall. Cholesterol or another sterol is required for growth. M. mycoiґdes causes pleuropneumonia in cattle, and other species comprise the pleuropneumonialike organisms (see under organism). The organisms are parasites and pathogens widely distributed on the mucous membranes of mammals and birds, and are common contaminants of animal cell cultures. The type species is M. mycoiґdes.
Medical dictionary. 2011.