Mycoplasmas are the aetiological agents of bovine pleuropneumonia in cattle caused by Mycoplasma mycoides subsp. mycoides, caprine pleuropneumonia in goats caused by M. mycoides subsp. capri, contagious agalactia caused by M. agalactiae, atrophic rhinitis and chronic pneumonia in pigs due to M. hyorhinis and M. hyopneumoniae, respectively, and chronic respiratory disease (CRD) in chicken caused by M. gallisepticum. A few species of Mycoplasma have been isolated from genital tracts of bovines associated with infertility and bovine bronchopneumonia and from goats and pigs suffering from pneumonia, peritonitis and arthritis.
The Mycoplasma organisms do not possess cell-wall and show a great deal of plasticity. The organisms may be cocci, filaments, rings and stellate. They are gram- negative organisms and are best stained with Giemsa stain. Mycoplasmas are fastidious in growth and need a sterol in the growth medium. Most of the stains are aerobic but a few need an atmosphere of 10% CO2.