Actinomycetes Flashcards
1
Q
Actinomyces israelii Disease
A
Actinomycosis (abscesses with draining sinus
tracts).
2
Q
Actinomyces israelii
Characteristics
A
- Anaerobic, gram-positive filamentous,
branching rods. - normal oral cavity flora
3
Q
Actinomyces israelii
Habitat and Transmission
A
- Human mouth->anaerobic crevices around teeth.
- dental disease or trauma.
- organism aspirated into lungs-> thoracic actinomycosis.
- Retained IUD-> pelvic actinomycosis.
- not communicable
4
Q
Actinomyces israelii
Pathogenesis & Clinical Findings
A
- No toxins or virulence factors.
- Organism forms sinus tracts, open onto skin containing sulfur granules (mats of intertwined filaments of bacteria).
- Lesion (mostly face & neck)-> hard, nontender slow developing swelling-> drains pus through sinus tracts.
- Hard, yellow sulfur granules formed in pus.
5
Q
Actinomyces israelii
Laboratory Diagnosis
A
- Gram-stained smear + anaerobic
culture on blood agar plate. - Sulfur granules visible in pus.
- No serologic tests.
6
Q
Actinomyces israelii
Treatment & Prevention
A
Penicillin G & No vaccine.
7
Q
Nocardia asteroides
Disease
A
Nocardiosis (lung & brain abscesses).
8
Q
Nocardia asteroides
Characteristics
A
- Aerobic, gram-positive filamentous, branch
ing rods. - Weakly acid-fast.
9
Q
Nocardia asteroides
Habitat & Transmission
A
- Soil.
- Airborne particles inhaled into lungs.
10
Q
Nocardia asteroides
Pathogenesis & Clinical Findings
A
- No toxins or virulence factors known.
- Immunosuppression & cancer (reduced cell-mediated immunity)-> infection
- pneumonia, lung abscess with cavity formation, lung nodules, or empyema.
- Lung-> organism spread-> brain->abscess.
11
Q
Nocardia asteroides
Laboratory Diagnosis
A
- Gram-stained smear & modified
Ziehl-Neelsen stain. - Aerobic culture on blood agar plate.
- gram + branching rods or filaments/weakly acid-fast in acid-fast stain & aerobic
growth seen - No serologic tests.
12
Q
Nocardia asteroides
Treatment & Prevention
A
Sulfonamides & No vaccine
