1. بسم الله الرحمن الرحيم 1 1 1

2. Head of Medical Microbiology Department
Branching
Branching
Branching
Branching
Branching
Branching Gram-Positive Bacilli
Dr. Manal El Said
Head of Medical Microbiology Department

3. Actinomycetes Actinomyces israelii Diseases Characteristics
Actinomycosis (abscesses with draining sinus tracts)
Characteristics
Anaerobic
Gram-positive filamentous, branching rods.

4. Habitat and Transmission
Actinomycetes
Actinomyces israelii
Habitat and Transmission
Habitat is human mouth, especially anaerobic crevices around the teeth.
Transmission occurs during dental disease or trauma.
It aspirated into lungs, causing thoracic actinomycosis.
Retained intrauterine device predisposes to pelvic actinomycosis.
Pathogenesis
Organism forms sinus tracts that open onto skin
It contain "sulfur granules," which are mats of intertwined filaments of bacteria.

5. Actinomycetes Actinomyces israelii Laboratory Diagnosis
Gram-stained smear plus anaerobic culture on blood agar plate.
"Sulfur granules" visible in the pus.

6. Actinomycetes Actinomyces israelii Prevention
Treatment
Penicillin G and surgical drainage.
Prevention
No vaccine or drug is available.

7. Habitat and Transmission
Nocardia asteroides
Diseases
Nocardiosis (especially lung and brain abscesses).
Characteristics
Aerobic
Gram-positive filamentous,
branching rods.
Weakly acid-fast.
Habitat and Transmission
Habitat is the soil.
Transmission is via airborne particles, which are inhaled into the lungs.

8. Nocardia asteroides Pathogenesis Laboratory Diagnosis
Predisposing factors: Immunosuppression & cancer
Laboratory Diagnosis
Gram-stained smear & modified Ziehl-Neelsen stain.
Aerobic culture on blood agar plate.
Rough, wrinkled colonies of an aerobic actinomycete: Nocardia asteroides

9. Nocardia asteroides Prevention Treatment Sulfonamides.
No vaccine or drug is available