Mycoplasmas

Mycoplasmas

1. Mycoplasmas (pleuropneumonia like organisms”(PPLO) In 1898, Nocard and Roux were the first to isolate a mycoplasma species in culture from bovine.

2. Mollicutes (The Mycoplamas ) The class Mollicutes has five orders and six families. The best studied genera are found in the orders Mycoplasmatales ( Mycoplasma, Ureaplasma ) Entomoplasmatales ( Entomoplasma , Mesoplasma , Spiroplasma ) Acholeplasmatales ( Acholeplasma ) Anaeroplasmatales ( Anaeroplasma , Asteroleplasma ) Haloplasmatales ( Haloplasma ) Although they evolved from ancestors with gram positive cell walls, they now lack cell walls and cannot synthesize peptidoglycan precursors . Many can pass through a bacterial filter Thus they are penicillin resistant but susceptible to lysis by osmotic shock and detergent treatment.

3. (lipoprotein)

4. Because they are bounded only by a plasma membrane, these prokaryotes are pleomorphic and vary in shape from spherical or pear-shaped organisms, about 0.3 to 0.8 min diameter, to branched or helical filaments They are among the smallest bacteria capable of self-reproduction Although most are non-motile , some can glide along liquid-covered surfaces Most are facultative anaerobes, but a few are obligate anaerobes. When growing on agar, most species form colonies with a “fried-egg” appearance because they grow into the agar surface at the center while spreading outward on the surface at the colony edges

5. Saprophytes, commensals, or parasites , and many are pathogens of plants, animals, or insects Incapable of synthesizing a number of macromolecules In addition to requiring sterols, they also need fatty acids, vitamins, amino acids, purines, and pyrimidines Widespread and can be isolated from animals, plants, the soil, sewage and even compost piles. Although their complex growth requirements can make their growth in pure cultures difficult , about 10% of the mammalian cell cultures in use are probably contaminated with mycoplasmas. In animals, mycoplasmas colonize mucous membranes and joints and often are associated with diseases of the respiratory and urogenital tracts Eaton's agar

6. Mycoplasmas cause several major diseases in livestock, for example, contagious bovine pleuropneumonia in cattle ( M. mycoides ), chronic respiratory disease in chickens ( M. gallisepticum ), and pneumonia in swine ( M. hyopneumoniae ). M. pneumonia causes primary atypical pneumonia in humans .

7. Diseases Caused by Mycoplasma Organism Disease M. pneumoniae Upper respiratory tract disease, tracheobronchitis, atypical pneumonia, (chronic asthma) M. hominis Pyelonephritis, pelvic inflammatory disease, postpartum fever M. genitalium Nongonococcal urethritis M. mycoides bovine pleuropneumonia in cattle M. gallisepticum chronic respiratory disease in chickens M. hyopneumoniae pneumonia in swine