Actinomyces. lecture slides

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Actinomyces. lecture slides

  1. 1. Actinomycetes Prof M.I.N. Matee Department of Microbiology and Immunology School of Medicine MUCHS Tuesday, November 8, 2005
  2. 2. General properties <ul><li>Gram positive branching filaments </li></ul><ul><li>Slow growers </li></ul><ul><li>Resemble Corynebacteria, mycobacteria and fungi </li></ul><ul><li>Include: </li></ul><ul><ul><ul><li>Actinomyces – anaerobe, normal flora </li></ul></ul></ul><ul><ul><ul><li>Norcadia – aerobe, saprophyte – PARTIALLY ACID FAST </li></ul></ul></ul><ul><ul><ul><li>Streptomyces - aerobe, saprophyte </li></ul></ul></ul>
  3. 3. Actinomyces <ul><li>Strict anaerobe </li></ul><ul><li>Gram positive </li></ul><ul><li>Non-motile </li></ul><ul><li>Non-proteolytic </li></ul><ul><li>Catalase negative </li></ul>
  4. 4. Motility From left to right: + – +
  5. 5. Actinomyces
  6. 6. C diptheriae : Gram stain
  7. 7. GRAM POSITIVE CELL ENVELOPE Cytoplasm Lipoteichoic acid Peptidoglycan-teichoic acid Cytoplasmic membrane Degradative enzyme
  8. 8. ACTINOMYCES <ul><li>Anaerobic, filamentous, gram positive bacillus </li></ul><ul><ul><li>Exhibit true branching </li></ul></ul><ul><li>“ Mykes” – Greek for “fungus” </li></ul><ul><li>Thought by early microbiologist to be fungi because of: </li></ul><ul><ul><li>Morphology </li></ul></ul><ul><ul><li>Disease they cause </li></ul></ul>
  9. 9. Actinomycosis <ul><li>Chronic suppurative disease </li></ul><ul><li>Spread by direct extension - sinuses </li></ul><ul><li>A israelii </li></ul><ul><li>A bovis – lumpy jaw in cattles </li></ul>
  10. 10. ACTINOMYCOSIS <ul><li>Form indurated masses with fibrous walls and central loculations with pus </li></ul><ul><ul><li>Pus contains &quot;Sulfur Granules&quot; </li></ul></ul><ul><ul><ul><li>Gritty, yellow white </li></ul></ul></ul><ul><ul><ul><li>Average diameter - 2mm </li></ul></ul></ul><ul><ul><ul><li>Composed of “mycelial” mass </li></ul></ul></ul><ul><li>  </li></ul><ul><li>Chronic infection </li></ul><ul><ul><li>Form burrowing sinus tracts to skin or mucus membranes </li></ul></ul><ul><ul><ul><li>Discharge purulent material </li></ul></ul></ul>
  11. 11. Actinomycosis - sulfur granule
  12. 12. III. Epidemiology <ul><li>-part of normal mouth and gut flora </li></ul><ul><li>- cervicofacial infection from tooth extraction or poor oral hygiene </li></ul><ul><li>- thoracic infection from aspiration </li></ul><ul><li>- abdominal infection from perforated gut or ruptured appendix </li></ul><ul><li>- foot infection from bacteria in soil </li></ul><ul><li>-infection mainly in immunocompromised patients </li></ul><ul><li>- not a communicable disease </li></ul>
  13. 13. Pulmonary Actinomycosis <ul><li>15% of cases </li></ul><ul><li>Aspiration of organism from the oropaharynx </li></ul><ul><li>Slowly progressive process involving lung and pleura </li></ul><ul><ul><li>May be mistaken for malignancy </li></ul></ul><ul><li>Chest pain, fever, wgt loss and hemoptysis </li></ul>
  14. 14. Laboratory diagnosis <ul><li>Specimens – pus, sputum, tissue biopsy </li></ul><ul><li>Microscopic examination – sulphur granules </li></ul><ul><li>Culture – thioglycolate medium and BHI </li></ul><ul><li>Incubation: anaerobic for 2 weeks </li></ul><ul><li>Gas liquid chromtography (GLC) of metabolic by-products </li></ul>
  15. 15. Anaerobic jar Figure 6.5
  16. 17. IV. Control <ul><li>- surgical drainage of abscess, </li></ul><ul><li>-parenteral penicillin for a few weeks, followed by oral for 6-12 months (very long term treatment) </li></ul><ul><li>-cephalosporins, erythromycin, clindamycin if pt allergic to pen </li></ul><ul><li>-prophylactic penicillin if pt has recurring infection, esp. before oral surgery </li></ul>
  17. 18. Nocardia asteroides
  18. 19. I. Organism <ul><li>-also actinomycete morphology </li></ul><ul><li>-produces shorter mycolic acids, hence partially acid fast </li></ul><ul><li>-aerobe, with both aerial and subsurface mycelia </li></ul>
  19. 20. Norcadiosis <ul><ul><ul><ul><li>Nocardiosis – is a localized or disseminated disease occurring after inhalation of organisms. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Pulmonary infections resemble tuberculosis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>may disseminate, with a predilection for the brain and meninges. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>It is usually a disease of compromised hosts </li></ul></ul></ul></ul>
  20. 21. II. Clinical (nocardiosis) <ul><li>-usually presents as lobar pneumonia in alcoholics or immunocompromised patients </li></ul><ul><li>-abscess formation in lung lobe </li></ul>
  21. 22. (nocardiosis) <ul><li>-usually presents as lobar pneumonia in alcoholics or immunocompromised patients </li></ul><ul><li>-abscess formation in lung lobe </li></ul><ul><li>-may spread to brain and CNS and cause meningitis or brain abscess </li></ul>
  22. 23. II. Clinical (nocardiosis) <ul><li>-usually presents as lobar pneumonia in alcoholics or immunocompromised patients </li></ul><ul><li>-abscess formation in lung lobe </li></ul><ul><li>-may spread to brain and CNS and cause meningitis or brain abscess </li></ul><ul><li>-can also on the foot from soil-based infections </li></ul>
  23. 24. III. Epidemiology <ul><li>-soil bacterium </li></ul><ul><li>-opportunistic pathogen </li></ul><ul><li>-lung infection from aspiration, dissemination to CNS, kidneys </li></ul>
  24. 25. Laboratory diagnosis <ul><li>Specimens – sputum, pus, spinal fluid, biopsy </li></ul><ul><li>Microscopy – coccoid, bacillary, tangled mass </li></ul><ul><li>Culture – on most ordinary media </li></ul><ul><li>Tissue section – methenamine-silver stain </li></ul>
  25. 26. IV. Treatment <ul><ul><ul><ul><li>Mycetoma – aminoglycosides </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Nocardiosis – sulfonamides or sxt </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Surgical debridement </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Underlying cause </li></ul></ul></ul></ul>
  26. 27. <ul><li>Actinomycetes such as Streptomyces have a world-wide distribution in soils. </li></ul><ul><li>They are important in aerobic decomposition of organic compounds and have an important role in biodegradation and the carbon cycle. </li></ul><ul><li>Actinomycetes are the main producers of antibiotics in industrial settings, being the source of most tetracyclines, macrolides (e.g. erythromycin), and aminoglycosides (e.g. streptomycin, gentamicin, etc.). </li></ul>
  27. 28. <ul><li>Thank you for listening </li></ul>

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