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Aerobic Actinomycetes and Anaerobic Actinomyces


Typical histopathology is presence of PAS-positive foamy macrophages ... whipplei (non-cultivable, diagnosis by typical histopathology combined with PCR) ... – PowerPoint PPT presentation

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Title: Aerobic Actinomycetes and Anaerobic Actinomyces

Aerobic Actinomycetes and Anaerobic Actinomyces
  • Dr. John R. Warren
  • Department of Pathology
  • Northwestern University
  • Feinberg School of Medicine
  • June 2007

Taxonomy of the Aerobic Actinomycetes
  • Gram-positive branching filaments that sporulate
    or fragment the aerobic
  • Actinomycetes (order Actinomycetales)
  • Aerobic Actinomycetes whose cell walls contain
    mycolic acid Nocardia species and Rhodococcus
    species (family Nocardiaceae)
  • Aerobic Actinomycetes whose cell walls lack
    mycolic acid Streptomyces species

Taxonomy of the Anaerobic Actinomyces
  • 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)
  • Actinomyces species member of the high GC group

Taxonomy of the Aerobic Actinomycetes Pathogenic
  • Nocardia
  • Actinomadura
  • Streptomyces
  • Rhodococcus
  • Gordonia
  • Tsukamurella
  • Tropheryma whipplei (Non-cultivable)

Aerobic Actinomycetes Natural Habitats
  • Nocardia species and other aerobic
  • Actinomycetes ubiquitous in soil and primarily
    responsible for decomposition of organic plant
  • Rhodococcus species present in the intestinal
    bacterial flora of grazing herbivores especially
  • Streptomyces species (gt3,000) widely distributed
    in soil

Anaerobic Actinomyces Natural Habitats
  • Anaerobic Actinomyces species
  • are normal inhabitants of the
  • mucous membranes of humans
  • and animals

Aerobic Actinomycetes Modes of Infection
  • Nocardia infection acquired by inhalation of or
    direct skin inoculation (traumatic) by
    environmental organisms
  • Rhodococcus infection due primarily to inhalation
    of organisms by animal handlers (horses, pigs,
  • Streptomyces are soil organisms that can infect
    traumatic wounds especially of the feet

Aerobic Actinomycetes Modes of Infection
  • Actinomadura species (A. madurae, A. latina, A.
    pelletieri) produce subcutaneous infections in
    tropical and subtropical countries with those who
    walk barefooted
  • Gordonia and Tsukamurella species are closely
    related to Rhodococcus, and are soil organisms
    considered opportunistic pathogens

Anaerobic Actinomyces Modes of Infection
  • Actinomyces invades normally
  • sterile tissue from endogenous
  • mucous membrane sites of
  • normal colonization

Aerobic Actinomycetes Types of Infectious Disease
  • Nocardia a facultative intracellular parasite
    that infects human macrophages and inhibits the
    fusion of phagosomes containing organisms with
  • Nocardia infections generally occur in
    immunocompromised patients or those with
    underlying pulmonary disease

Aerobic Actinomycetes Types of Infectious Disease
  • Nocardia asteroides complex N. asteroides sensu
    stricto type VI, N. abscessus, N. farcinica, and
    N. nova, major cause of pulmonary infection
  • N. otitidiscavarium infrequent cause of systemic
  • N. brasiliensis inoculated into subcutaneous
    tissue of foot produces actinomycotic mycetomas

Aerobic Actinomycetes Types of Infectious Disease
  • Nocardial pneumonia occurs primarily in
    immunocompromised hosts and produces necrotizing
    pyogranuloma formation.
  • Extrapulmonary dissemination (50) and
    metastatic brain abscess (30) complications of
    nocardial pneumonia.
  • Actinomycotic mycetoma (pyogenic subcutaneous
    infection) causes local tissue destruction
    including bone

Aerobic Actinomycetes Types of Infectious Disease
  • Rhodococcus equi infects macrophages inhibiting
    phagolysosome fusion, and produces pulmonary
    disease with cavitation. Infection occurs in
    immunocompromised (especially HIV-infected)
    individuals who handle horses.
  • R. equi disseminates to other organs including
    the brain and subcutaneous tissue

Aerobic Actinomycetes Types of Infectious Disease
  • Streptomyces (S. anulatus formerly S. griseus,
    and S. somaliensis) associated with actinomycotic
    mycetoma in warm climates.
  • S. somaliensis a frequent cause of actinomycotic
    mycetomas of the head and neck.

Aerobic Actinomycetes Types of Infectious Disease
  • Whipples disease diarrhea, weight loss,
    lymphadenopathy, fever, and arthralgia
  • Typical histopathology is presence of
    PAS-positive foamy macrophages infiltrating the
    lamina propria of the small intestine
  • Caused by intracellular infection of macrophages
    by Tropheryma whipplei (non-cultivable, diagnosis
    by typical histopathology combined with PCR)

Anaerobic Actinomyces Types of Infectious Disease
  • Actinomyces israelii causes actinomycosis in
    which chronic granulomas become suppurative.
    Cervicofacial actinomycosis most common (60),
    followed by abdominal (20) and pulmonary (15).
  • Tissue pus contains sulfur granules, a tangled
    mass of branching bacteria. Presence of sulfur
    granules establishes a diagnosis of

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Aerobic Actinomycetes Identification
  • Nocardia and Rhodococcus (potentially pathogenic)
    and Streptomyces (less frequently pathogenic)
    obligate aerobes
  • Nocardia asteroides complex organisms thin
    (0.5-1.0 ?m) filaments up to 20 ?m in length
    demonstrating beaded gram-positivity
  • Rhodococcus equi gram-positive coccobacilli

Aerobic Actinomycetes Identification
  • Nocardia grows in a variety of media including
    blood and chocolate agars, Sabourauds dextrose
    agar without chloramphenicol, Lowenstein-Jensen
    slant, Middlebrook agar, and thioglycolate or
    trypticase soy broth.
  • Growth is slow requiring 5-7 days up to 3 weeks
    for colony formation at 25o to 37oC.
  • Growth in culture of Actinomadura and
    Streptomyces similar to Nocardia

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Aerobic Actinomycetes Identification
  • Nocardia and Rhodococcus are partially acid-fast
    positive by modified Kinyoun stain (1 H2SO4 used
    as decolorizing agent)
  • Resistance or sensitivity of growth in glycerol
    broth to lysozyme
  • Urease activity
  • Decomposition of the substrates casein, tyrosine,
    xanthine, and hypoxanthine

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Aerobic Actinomycetes Identification
  • Lysozyme1
  • Nocardia asteroides
  • N. brasilensis
  • N. otitidiscavarium
  • Streptomyces anulatus
  • S. somaliensis
  • Actinomadura madura
  • A. pelletieri
  • 1Resistance of growth in glyercol broth to
  • 2Christensen urea slant

Aerobic Actinomycetes Decomposition of Substrates
  • Cas
    Tyr Xan Hyp
  • Nocardia asteroides1
  • N. brasilensis
  • N. otitidiscavarium
  • Strepomyces anulatus
  • S. somaliensis
  • Actinomadura madura3
  • A. pelletieri3
  • 1Susceptibility testing required, N. farcinica
    characteristically resistant to cefotaxime, and
    demonstrates variable resistance to ceftriaxone.
  • 2NR not reported.
  • 3A. madura esculin decomposition positive, A.
    pelletieri esculin decomposition negative.

Antimicrobial Susceptibility1 of Nocardia
asteroides complex ( Susceptible)
  • Sul Cip Ami Cef Ctr Imi
  • N. asteroides2 96-99 38-98 100 94-100 94-100 77-98
  • N. farcinica 89-100 68-88 100 0-7 0-73 64-87
  • N. nova 89-97 0 100 87-100 100 100
  • 1Sulsulfamethoxazole,Cipciprofloxacin,Amiamikac
    in, Cefcefotaxime,Ctrceftriaxone,Imiimipenem
  • 2Nocardia asteroides sensu stricto type VI
  • Sorrell, T.C., Mitchell, D.H., and Iredell,
    J.R.. Chapter 252. Nocardia
  • species. In Mandell, Douglas, and Bennetts
    Principles and Practice of
  • Infectious Dieseses. G.L. Mandell, J.E. Bennett,
    R. Dolin, Eds. Elsevier
  • Churchill Livinstone, 2005.

Aerobic Actinomycetes Identification
  • Rhodococcus, Gordonia, and Tsukamurella difficult
    to characterize biochemically with identification
    based on partial acid-fastness, colony
    morphology, and 16S rRNA gene sequence analysis
  • Rhodococcus slimy, salmon-pink colonies
  • Gordonia smooth, beige to salmon-pink colonies
  • Tsukamurella cerebroid, cream colonies

Anaerobic Actinomyces Identification
  • Actinomyces israelii anaerobic with clinical
    strains varying from obligate anaerobes to
  • A. israelii definitively identified by detection
    using gas liquid chromato- graphy (GLC) of acetic
    and lactic acid as end products of carbohydrate

Recommended Reading
  • Winn, W., Jr., Allen, S., Janda, W., Koneman,
  • E., Procop, G., Schreckenberger, P., Woods,
  • G.
  • Konemans Color Atlas and Textbook of
  • Diagnostic Microbiology, Sixth Edition,
  • Lippincott Williams Wilkins, 2006
  • Chapter 15. Aerobic Actinomycetes
  • Chapter 16. The Anaerobic Bacteria

Recommended Reading
  • Murray, P., Baron, E., Jorgensen, J., Landry, M.,
    Pfaller, M.
  • Manual of Clinical Microbiology, 9th Edition, ASM
  • 2007
  • Conville, P.S., and Witebsky, F.G. Chapter 35.
    Nocardia, Rhodococcus, Gordonia, Actinomadura,
    Streptomyces, and Other Aerobic Actinomycetes
  • Koenoenen, E., and Wade, W.G. Chapter 56.
    Propionibacterium, Lactobacillus, Actinomyces,
    and Other Non-Spore-Forming Anaerobic
    Gram-Positive Rods