10 aerobic actinomycetes-and_anaerobic_____actinomyces_v1-_3


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10 aerobic actinomycetes-and_anaerobic_____actinomyces_v1-_3

  1. 1. Aerobic Actinomycetes and Anaerobic Actinomyces Dr. John R. Warren Department of Pathology Northwestern University Feinberg School of Medicine June 2007
  2. 2. Taxonomy of the Aerobic Actinomycetes <ul><li>Gram-positive branching filaments that sporulate or fragment: the aerobic </li></ul><ul><li>Actinomycetes (order Actinomycetales ) </li></ul><ul><li>Aerobic Actinomycetes whose cell walls contain mycolic acid: Nocardia species and Rhodococcus species (family Nocardiaceae ) </li></ul><ul><li>Aerobic Actinomycetes whose cell walls lack mycolic acid: Streptomyces species </li></ul>
  3. 3. Taxonomy of the Anaerobic Actinomyces <ul><li>Anaerobic non-sporulating gram-positive rods consist of two groups based on guanosine (G) plus cytosine (C) DNA content: Low mole percent (30-53%) and high mole percent (49-68%) </li></ul><ul><li>Actinomyces species member of the high G+C group </li></ul>
  4. 4. Taxonomy of the Aerobic Actinomycetes : Pathogenic Genera <ul><li>Nocardia </li></ul><ul><li>Actinomadura </li></ul><ul><li>Streptomyces </li></ul><ul><li>Rhodococcus </li></ul><ul><li>Gordonia </li></ul><ul><li>Tsukamurella </li></ul><ul><li>Tropheryma whipplei (Non-cultivable) </li></ul>
  5. 5. Aerobic Actinomycetes : Natural Habitats <ul><li>Nocardia species and other aerobic </li></ul><ul><li>Actinomycetes ubiquitous in soil and primarily responsible for decomposition of organic plant matter </li></ul><ul><li>Rhodococcus species present in the intestinal bacterial flora of grazing herbivores especially horses </li></ul><ul><li>Streptomyces species (>3,000) widely distributed in soil </li></ul>
  6. 6. Anaerobic Actinomyces : Natural Habitats <ul><li>Anaerobic Actinomyces species </li></ul><ul><li>are normal inhabitants of the </li></ul><ul><li>mucous membranes of humans </li></ul><ul><li>and animals </li></ul>
  7. 7. Aerobic Actinomycetes : Modes of Infection <ul><li>Nocardia infection acquired by inhalation of or direct skin inoculation (traumatic) by environmental organisms </li></ul><ul><li>Rhodococcus infection due primarily to inhalation of organisms by animal handlers (horses, pigs, cattle) </li></ul><ul><li>Streptomyces are soil organisms that can infect traumatic wounds especially of the feet </li></ul>
  8. 8. Aerobic Actinomycetes : Modes of Infection <ul><li>Actinomadura species ( A. madurae, A. latina, A. pelletieri ) produce subcutaneous infections in tropical and subtropical countries with those who walk barefooted </li></ul><ul><li>Gordonia and Tsukamurella species are closely related to Rhodococcus , and are soil organisms considered opportunistic pathogens </li></ul>
  9. 9. Anaerobic Actinomyces : Modes of Infection <ul><li>Actinomyces invades normally </li></ul><ul><li>sterile tissue from endogenous </li></ul><ul><li>mucous membrane sites of </li></ul><ul><li>normal colonization </li></ul>
  10. 10. Aerobic Actinomycetes : Types of Infectious Disease <ul><li>Nocardia a facultative intracellular parasite that infects human macrophages and inhibits the fusion of phagosomes containing organisms with lysosomes. </li></ul><ul><li>Nocardia infections generally occur in immunocompromised patients or those with underlying pulmonary disease </li></ul>
  11. 11. Aerobic Actinomycetes : Types of Infectious Disease <ul><li>Nocardia asteroides complex: N . asteroides sensu stricto type VI, N . abscessus, N. farcinica , and N . nova , major cause of pulmonary infection </li></ul><ul><li>N. otitidiscavarium infrequent cause of systemic infection </li></ul><ul><li>N . brasiliensis inoculated into subcutaneous tissue of foot produces actinomycotic mycetomas </li></ul>
  12. 12. Aerobic Actinomycetes : Types of Infectious Disease <ul><li>Nocardial pneumonia occurs primarily in immunocompromised hosts and produces necrotizing pyogranuloma formation. </li></ul><ul><li>Extrapulmonary dissemination (~50%) and metastatic brain abscess (~30%) complications of nocardial pneumonia. </li></ul><ul><li>Actinomycotic mycetoma (pyogenic subcutaneous infection) causes local tissue destruction including bone </li></ul>
  13. 13. Aerobic Actinomycetes : Types of Infectious Disease <ul><li>Rhodococcus equi infects macrophages inhibiting phagolysosome fusion, and produces pulmonary disease with cavitation. Infection occurs in immunocompromised (especially HIV-infected) individuals who handle horses. </li></ul><ul><li>R. equi disseminates to other organs including the brain and subcutaneous tissue </li></ul>
  14. 14. Aerobic Actinomycetes : Types of Infectious Disease <ul><li>Streptomyces ( S. anulatus formerly S. griseus, and S. somaliensis ) associated with actinomycotic mycetoma in warm climates. </li></ul><ul><li>S. somaliensis a frequent cause of actinomycotic mycetomas of the head and neck. </li></ul>
  15. 15. Aerobic Actinomycetes : Types of Infectious Disease <ul><li>Whipple’s disease: diarrhea, weight loss, lymphadenopathy, fever, and arthralgia </li></ul><ul><li>Typical histopathology is presence of PAS-positive foamy macrophages infiltrating the lamina propria of the small intestine </li></ul><ul><li>Caused by intracellular infection of macrophages by Tropheryma whipplei (non-cultivable, diagnosis by typical histopathology combined with PCR) </li></ul>
  16. 16. Anaerobic Actinomyces : Types of Infectious Disease <ul><li>Actinomyces israelii causes actinomycosis in which chronic granulomas become suppurative. Cervicofacial actinomycosis most common (~60%), followed by abdominal (20%) and pulmonary (15%). </li></ul><ul><li>Tissue pus contains sulfur granules, a tangled mass of branching bacteria. Presence of sulfur granules establishes a diagnosis of actinomycosis. </li></ul>
  17. 20. Aerobic Actinomycetes : Identification <ul><li>Nocardia and Rhodococcus (potentially pathogenic) and Streptomyces (less frequently pathogenic) obligate aerobes </li></ul><ul><li>Nocardia asteroides complex organisms thin (0.5-1.0  m) filaments up to 20  m in length demonstrating beaded gram-positivity </li></ul><ul><li>Rhodococcus equi gram-positive coccobacilli </li></ul>
  18. 21. Aerobic Actinomycetes : Identification <ul><li>Nocardia grows in a variety of media including blood and chocolate agars, Sabouraud’s dextrose agar without chloramphenicol, Lowenstein-Jensen slant, Middlebrook agar, and thioglycolate or trypticase soy broth. </li></ul><ul><li>Growth is slow requiring 5-7 days up to 3 weeks for colony formation at 25 o to 37 o C. </li></ul><ul><li>Growth in culture of Actinomadura and Streptomyces similar to Nocardia </li></ul>
  19. 25. Aerobic Actinomycetes : Identification <ul><li>Nocardia and Rhodococcus are partially acid-fast positive by modified Kinyoun stain (1% H 2 SO 4 used as decolorizing agent) </li></ul><ul><li>Resistance or sensitivity of growth in glycerol broth to lysozyme </li></ul><ul><li>Urease activity </li></ul><ul><li>Decomposition of the substrates casein, tyrosine, xanthine, and hypoxanthine </li></ul>
  20. 28. Aerobic Actinomycetes : Identification <ul><li> Lysozyme 1 Urease 2 </li></ul><ul><li>Nocardia asteroides + + </li></ul><ul><li>N. brasilensis + + </li></ul><ul><li>N. otitidiscavarium + + </li></ul><ul><li>Streptomyces anulatus – +/– </li></ul><ul><li>S. somaliensis – – </li></ul><ul><li>Actinomadura madura – – </li></ul><ul><li>A. pelletieri – – </li></ul><ul><li>1 Resistance of growth in glyercol broth to lysozyme </li></ul><ul><li>2 Christensen urea slant </li></ul>
  21. 29. Aerobic Actinomycetes : Decomposition of Substrates <ul><li>Cas Tyr Xan Hyp </li></ul><ul><li>Nocardia asteroides 1 – – – – </li></ul><ul><li>N. brasilensis + + – + </li></ul><ul><li>N. otitidiscavarium – – + + </li></ul><ul><li>Strepomyces anulatus + + + NR 2 </li></ul><ul><li>S. somaliensis + + – + </li></ul><ul><li>Actinomadura madura 3 + + – + </li></ul><ul><li>A. pelletieri 3 + + – + </li></ul><ul><li>1 Susceptibility testing required, N. farcinica characteristically resistant to cefotaxime, and demonstrates variable resistance to ceftriaxone. </li></ul><ul><li>2 NR = not reported. </li></ul><ul><li>3 A . madura esculin decomposition positive, A . pelletieri esculin decomposition negative. </li></ul>
  22. 30. Antimicrobial Susceptibility 1 of Nocardia asteroides complex (% Susceptible) <ul><li>Sul Cip Ami Cef Ctr Imi </li></ul><ul><li>N. asteroides 2 96-99 38-98 100 94-100 94-100 77-98 </li></ul><ul><li>N. farcinica 89-100 68-88 100 0-7 0-73 64-87 </li></ul><ul><li>N. nova 89-97 0 100 87-100 100 100 </li></ul><ul><li>1 Sul=sulfamethoxazole,Cip=ciprofloxacin,Ami=amikacin, Cef=cefotaxime , Ctr=ceftriaxone ,Imi=imipenem </li></ul><ul><li>2 Nocardia asteroides sensu stricto type VI </li></ul><ul><li>Sorrell, T.C., Mitchell, D.H., and Iredell, J.R.. Chapter 252. Nocardia </li></ul><ul><li>species. In Mandell, Douglas, and Bennett’s Principles and Practice of </li></ul><ul><li>Infectious Dieseses. G.L. Mandell, J.E. Bennett, R. Dolin, Eds. Elsevier </li></ul><ul><li>Churchill Livinstone, 2005. </li></ul>
  23. 31. Aerobic Actinomycetes : Identification <ul><li>Rhodococcus , Gordonia, and Tsukamurella difficult to characterize biochemically with identification based on partial acid-fastness, colony morphology, and 16S rRNA gene sequence analysis </li></ul><ul><li>Rhodococcus : slimy, salmon-pink colonies </li></ul><ul><li>Gordonia : smooth, beige to salmon-pink colonies </li></ul><ul><li>Tsukamurella : cerebroid, cream colonies </li></ul>
  24. 32. Anaerobic Actinomyces : Identification <ul><li>Actinomyces israelii anaerobic with clinical strains varying from obligate anaerobes to microaerophilic </li></ul><ul><li>A . israelii definitively identified by detection using gas liquid chromato- graphy (GLC) of acetic and lactic acid as end products of carbohydrate metabolism </li></ul>
  25. 33. Recommended Reading <ul><li>Winn, W., Jr., Allen, S., Janda, W., Koneman, </li></ul><ul><li>E., Procop, G., Schreckenberger, P., Woods, </li></ul><ul><li>G. </li></ul><ul><li>Koneman’s Color Atlas and Textbook of </li></ul><ul><li>Diagnostic Microbiology , Sixth Edition, </li></ul><ul><li>Lippincott Williams & Wilkins, 2006: </li></ul><ul><li>Chapter 15. Aerobic Actinomycetes </li></ul><ul><li>Chapter 16. The Anaerobic Bacteria </li></ul>
  26. 34. Recommended Reading <ul><li>Murray, P., Baron, E., Jorgensen, J., Landry, M., Pfaller, M. </li></ul><ul><li>Manual of Clinical Microbiology, 9th Edition, ASM Press, </li></ul><ul><li>2007: </li></ul><ul><li>Conville, P.S., and Witebsky, F.G. Chapter 35. Nocardia, Rhodococcus, Gordonia, Actinomadura , Streptomyces, and Other Aerobic Actinomycetes </li></ul><ul><li>Koenoenen, E., and Wade, W.G. Chapter 56. Propionibacterium, Lactobacillus, Actinomyces, and Other Non-Spore-Forming Anaerobic Gram-Positive Rods </li></ul>