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Mycoplasma and Ureaplasma

Mycoplasma and Ureaplasma. Family: Mycoplasmataceae. Genus: Mycoplasma Species: M. pneumoniae Species: M. hominis Species: M. genitalium Genus: Ureaplasma Species: U. urealyticum. Diseases Caused by Mycoplasma.

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Mycoplasma and Ureaplasma

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  1. Mycoplasma and Ureaplasma

  2. Family: Mycoplasmataceae • Genus: Mycoplasma • Species: M. pneumoniae • Species: M. hominis • Species: M. genitalium • Genus: Ureaplasma • Species: U. urealyticum

  3. Diseases Caused by Mycoplasma N.B. Other organisms infect humans but their disease association is not known.

  4. Morphology and Physiology • Smallest free-living bacteria (0.2 - 0.8 :m) • Small genome size • Require complex media for growth • Facultative anaerobes • Except M. pneumoniae - strict aerobe • Lack a cell wall • Grow slowly by binary fission • “Fried egg” colonies • M. pneumoniae colonies have a granular appearance

  5. “Fried Egg” Colonies of Mycoplasmas

  6. Morphology and Physiology • Smallest free-living bacteria • Small genome size • Require complex media for growth • Facultative anaerobes • Except M.. pneumoniae - strict aerobe • Lack a cell wall • Grow slowly by binary fission • “Fried egg” colonies • Ureaplasma - T strains • Require sterols for growth

  7. Differentiation of Species • M. pneumoniae - glucose • M. hominis - arginine • U. urealyticum - urea • M. genitalium - difficult to culture

  8. Pathogenesis - Mycoplasma • Adherence • P1 pili (M. pneumoniae) • Movement of cilia ceases • Clearance mechanism stops resulting in cough • Toxic metabolic products • Peroxide and superoxide • Inhibition of catalase • Immunopathogenesis • Activate macrophages • Stimulate cytokine production • Suprerantigen (M. pneumoniae)

  9. Mycoplasma pneumoniae • Tracheobronchitis • Atypical pneumonia (walking pneumonia)

  10. Epidemiology - M. pneumoniae • Occurs worldwide • No seasonal variation • Proportionally higher in summer and fall • Epidemics occur every 4-8 year

  11. Epidemiology - M. pneumoniae • Spread by aerosol route (Confined populations) • Disease of the young (5-20 years), although all ages are at risk

  12. Epidemiology - M. pneumoniae • Estimated pneumonia in USA per year – 2 million • Estimated respiratory disease in USA per year – 20 million • Non-reportable disease

  13. Clinical Syndrome - M. pneumoniae • Tracheobronchitis • 70-80% of infections • Pneumonia • Approximately 10% of infections • Mild disease but long duration • “Primary atypical pneumonia” • “Walking pneumonia”

  14. Clinical Syndrome - M. pneumoniae • Incubation - 2-3 weeks • Fever, headache and malaise • Persistent non-productive cough • Respiratory symptoms • Radiological signs precede symptoms • Organisms persist • Slow resolution • Rarely fatal

  15. Immunity - M. pneumoniae • Complement activation • Alternative pathway • Phagocytic cells • Antibodies • IgA important • Delayed type hypersensitivity • More severe disease (immunopathogenesis)

  16. Laboratory Diagnosis - M. pneumoniae • Microscopy • Difficult to stain • Can help eliminate other organisms • Culture (definitive diagnosis) • Sputum (usually scant) or throat washings • Special transport medium needed • Must suspect M. pneumoniae • May take 2-3 weeks

  17. Laboratory Diagnosis - M. pneumoniae • Serology • Complement fixation • May take 4-6 weeks • Fourfold rise in titer • Cold agglutinins • 1/3 - 2/3 of patients • I antigen • Appear first • Non-specific • Presumptive diagnosis • ELISA • Not commercially available

  18. Laboratory Diagnosis - M. pneumoniae • Molecular diagnosis • PCR-based tests are being developed and these are expected to be the diagnostic test of choice in the future.

  19. Treatment and PreventionM. pneumoniae • Treatment • Tetracycline or erythromycin • Newer fluoroquinolones • Can’t use cell wall synthesis inhibitors • Prevention • Avoid close contact • No vaccine

  20. M. hominis, M. genitalium andU. urealyticum • Clinical syndromes • M. hominis - pyleonephritis, pelvic inflammatory disease and postpartum fever • M. genitalium - nongonococcal urethritis • U. urealyticum - nongonococcal urethritis • Epidemiology • Colonization at birth - usually cleared • Colonization with M. hominis - 15% • Colonization with U. urealyticum - 45% -75% • Colonization with M. genitalium - ??

  21. M. hominis, M. genitalium and U. urealyticum • Laboratory diagnosis • Culture (except M. genitalium) • Treatment and prevention • Treatment • Tetracycline or erythromycin • Prevention • Abstinence or barrier protection • No vaccine

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