Mycoplasmataceae

Mycoplasmataceae is a family of small, wall-less bacteria within the class Mollicutes, order Mycoplasmatales. Members are among the smallest self-replicating organisms. They lack a peptidoglycan cell wall, have a pleomorphic morphology, and possess a cytoplasmic membrane that incorporates sterols from the environment. Genomes are compact, often under 1 million base pairs, and many species rely on host-derived nutrients.

Taxonomy and genera: The family is best known for the genera Mycoplasma and Ureaplasma, which include species of medical and veterinary importance. Classification within the Mollicutes has shifted over time, and related organisms have been placed in other families as taxonomy has evolved.

Ecology and biology: Mycoplasmataceae members colonize mucosal surfaces and other host environments. They are typically slow-growing and require rich, specialized culture media supplemented with serum and cholesterol. Their lack of a cell wall also confers resistance to many antibiotics that target cell walls and contributes to their ecological success on hosts.

Pathogenicity and clinical relevance: In humans, Mycoplasma pneumoniae causes atypical pneumonia and tracheobronchitis; M. genitalium and M. hominis, as well as Ureaplasma urealyticum, are associated with urogenital infections including urethritis and pelvic inflammatory disease. Animal species within or related to the family cause diseases such as pleuropneumonia, mastitis, and reproductive disorders. Some species are commensals or environmental associates.

Diagnosis and treatment: Detection relies on nucleic acid amplification tests and culture in specialized media; serology is used for some infections. Because they lack a cell wall, beta-lactam antibiotics are ineffective; effective options include macrolides, tetracyclines, or fluoroquinolones, with regional resistance issues noted for M. genitalium.