mykoplasma

Mycoplasma is a genus of small bacteria in the class Mollicutes. They are among the smallest free-living organisms and lack a rigid cell wall, making them pleomorphic and poorly stainable by standard Gram methods. They require cholesterol for membrane integrity and have compact genomes. Their growth is fastidious, typically requiring specialized media.

Ecology and pathogenicity: Mycoplasmas commonly inhabit mucosal surfaces of humans and animals. Many species are harmless commensals, but several cause disease. In humans, notable pathogens include Mycoplasma pneumoniae (atypical pneumonia and bronchitis), Mycoplasma genitalium and Ureaplasma urealyticum (nongonococcal urethritis and other urogenital infections), and Mycoplasma hominis (pelvic inflammatory disease in some cases).

In animals, pathogens such as Mycoplasma bovis and Mycoplasma mycoides affect cattle and other ruminants, causing pneumonia, arthritis, mastitis, and reproductive problems. Transmission is typically respiratory for human-associated species and contact or environmental for veterinary species; some are considered zoonotic or have economic significance in livestock.

Diagnosis and treatment: Diagnosis relies on nucleic acid amplification tests and serology; culture is possible but slow and requires enriched, cholesterol-supplemented media. Because they lack a cell wall, mycoplasmas are inherently resistant to beta-lactam antibiotics; treatment options target protein synthesis or DNA replication, such as macrolides, tetracyclines, and certain fluoroquinolones.

Research and clinical considerations: Accurate identification is important due to colonization versus infection and potential co-infections. Handling and containment follow standard microbiology biosafety practices, reflecting their status as human and animal pathogens in some contexts.