Mycoplasma and Ureaplasma Dr. R. K. Kalyan Associate Professor Microbiology Dept. Kgmu mycoplasma

MYCOPLASMA and Ureaplasma

• Dr. R.K.Kalyan
• Associate Professor
• Microbiology Dept. KGMU

MYCOPLASMA

• Smallest free-living micro organisms, lack cell wall.
• Size varies from spherical shape(125-250nm to longer branching filaments 500-1000 nm in size. Many can pass through a bacterial filter.
• 1st member of this group – isolated by Nocard & Roux (1898) – caused bovine
• pleuropneumonia.
• Later, many similar isolates were obtained from animals, human beings, plants & environmental sources – called as “pleuropneumonia like organisms”(PPLO).

MYCOPLASMA

• Eaton (1944) first isolated the causative agent of the disease in hamsters and cotton rates.
• Also known as Eaton agent.
• 1956- PPLO replaced by Mycoplasma.
• Myco : fungus like branching filaments
• Plasma : plasticity
• highly pleomorphic – no fixed shape or size - Lack cell wall.

Morphology and Physiology

• Small genome size (M. pneumoniae is ~800 Kbp)
• Require complex media for growth
• Facultative anaerobes
• Except M. pneumoniae - strict aerobe
• No cell wall means these are resistant to penicillins, cephalosporins and vancomycin, etc.
• Grow slowly by binary fission
• Doubling time can be as long as 16 hours, extended incubation needed

Morphology and Physiology cont’

• Require complex media for growth, including sterols
• Major antigenic determinants are glycolipids and proteins, some cross reaction with human tissues.
• Requirements for growth allow one to differentiate between species

Morphology and Physiology cont’

• M. pneumoniae - glucose
• M. hominis - arginine
• U. urealyticum - urea (buffered media due to growth inhibition by alkaline media)
• M. genitalium - difficult to culture