Gram stain: Cell shape: These organisms lack a cell wall and are therefore extremely variable in shape. To prevent lysis they have a strong cell membrane imbedded with sterols. When grown on agar medium, the colonies exhibit a characteristic "fried egg" appearance. Arrangement: Oxygen requirements: Other:
Habitat: some species are found in soil, sewage, plants and animals.
Pathogenicity:M. pneumoniae is the most significant pathogen in this group. It has been associated with otitis media and "walking pneumonia" (responsible for 1/5 of all bacterial pneumonias.
Transmission: Inhalation of aerosolized droplets.
Diagnosis: fluorescent antibody methods, ELISA tests, blood test for complement fixing antibodies.
Treatment: tetracycline and erythromycin; antibodies that act against cell wall synthesis are completely ineffective!
Mycoplasma spp.
