mykoplasmat

Mykoplasmat, known in English as mycoplasmas, are a group of very small bacteria within the class Mollicutes. They are among the smallest free-living organisms and are distinguished by the absence of a cell wall and by pleomorphic, membrane-rich cells that often require cholesterol for membrane stability.

They lack rigid peptidoglycan-based walls, making them intrinsically resistant to beta-lactam antibiotics. They have flexible cytoplasmic membranes and generally grow slowly on specialized culture media that supply sterols and other nutrients. Because they are fragile outside host tissues, isolation often requires enriched media or culture systems.

Many species colonize mucosal surfaces in humans and animals and can cause respiratory, urogenital, or systemic infections. Notable human pathogens include Mycoplasma pneumoniae, which causes atypical pneumonia, and Mycoplasma genitalium, a cause of non-gonococcal urethritis. Other species such as M. hominis and M. fermentans are associated with various infections; in animals, M. bovis, M. gallisepticum, and M. agalactiae affect cattle, poultry, and small ruminants.

Diagnosis is based on a combination of culture on specialized media, molecular methods (PCR), and serology. Treatment relies on antibiotics that inhibit protein synthesis or DNA replication—macrolides, tetracyclines, or fluoroquinolones—since beta-lactams are ineffective due to the lack of a cell wall. Resistance is an emerging concern for some species.

Ecology and significance: Mycoplasmas are common members of the microbiota of humans and animals and can act as pathogens under certain conditions. They are also studied in research and diagnostic contexts due to their small genome and unique biology.