The Mycoplasma represent the smallest and simplest self-replicating bacteria. They have no cell wall and are parasites that inhabit the mucus membranes of the respiratory and urogenital tracts.
Many species are part of the normal flora.
These organisms are a frequent cell culture contaminant. There are also elongated and filamentous forms. The organisms possess a protein attachment factor termed P1 that interacts with a specific cellular receptor and allows adherence to respiratory epithelium. Mycoplasma produce primary atypical pneumonia. This disease can range from subclinical to bronchopneumonia, often with a gradual onset and mild to moderate severity.