Title: Aerobic Actinomycetes and Anaerobic Actinomyces
1Aerobic Actinomycetes and Anaerobic Actinomyces
- Dr. John R. Warren
- Department of Pathology
- Northwestern University
- Feinberg School of Medicine
- June 2007
2Taxonomy 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
3Taxonomy 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
4Taxonomy of the Aerobic Actinomycetes Pathogenic
Genera
- Nocardia
- Actinomadura
- Streptomyces
- Rhodococcus
- Gordonia
- Tsukamurella
- Tropheryma whipplei (Non-cultivable)
5Aerobic Actinomycetes Natural Habitats
- Nocardia species and other aerobic
- Actinomycetes ubiquitous in soil and primarily
responsible for decomposition of organic plant
matter - Rhodococcus species present in the intestinal
bacterial flora of grazing herbivores especially
horses - Streptomyces species (gt3,000) widely distributed
in soil
6Anaerobic Actinomyces Natural Habitats
- Anaerobic Actinomyces species
- are normal inhabitants of the
- mucous membranes of humans
- and animals
7Aerobic 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,
cattle) - Streptomyces are soil organisms that can infect
traumatic wounds especially of the feet
8Aerobic 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
9Anaerobic Actinomyces Modes of Infection
- Actinomyces invades normally
- sterile tissue from endogenous
- mucous membrane sites of
- normal colonization
10Aerobic Actinomycetes Types of Infectious Disease
- Nocardia a facultative intracellular parasite
that infects human macrophages and inhibits the
fusion of phagosomes containing organisms with
lysosomes. - Nocardia infections generally occur in
immunocompromised patients or those with
underlying pulmonary disease
11Aerobic 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
infection - N. brasiliensis inoculated into subcutaneous
tissue of foot produces actinomycotic mycetomas
12Aerobic 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
13Aerobic 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
14Aerobic 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.
15Aerobic 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)
16Anaerobic 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
actinomycosis.
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20Aerobic 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
21Aerobic 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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25Aerobic 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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28Aerobic Actinomycetes Identification
- Lysozyme1
Urease2 - Nocardia asteroides
- N. brasilensis
- N. otitidiscavarium
- Streptomyces anulatus
/ - S. somaliensis
- Actinomadura madura
- A. pelletieri
- 1Resistance of growth in glyercol broth to
lysozyme - 2Christensen urea slant
29Aerobic Actinomycetes Decomposition of Substrates
- Cas
Tyr Xan Hyp - Nocardia asteroides1
- N. brasilensis
- N. otitidiscavarium
- Strepomyces anulatus
NR2 - 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.
30Antimicrobial 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.
-
31Aerobic 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
32Anaerobic Actinomyces Identification
- Actinomyces israelii anaerobic with clinical
strains varying from obligate anaerobes to
microaerophilic - A. israelii definitively identified by detection
using gas liquid chromato- graphy (GLC) of acetic
and lactic acid as end products of carbohydrate
metabolism
33Recommended 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
34Recommended Reading
- Murray, P., Baron, E., Jorgensen, J., Landry, M.,
Pfaller, M. - Manual of Clinical Microbiology, 9th Edition, ASM
Press, - 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