Actinomycetes

1
Actinomycetes
By
Dr. Emad AbdElhameed Morad
Lecturer of Medical Microbiology and Immunology
2
(No Transcript)
3

• Actinomycetes are filamentous Gram positive
  bacilli and some of them are acid fast.
• The genera of medical importance are
• 1)- Actinomyces which cause actinomycosis.
• 2)- Actinomadura which cause mycetoma.
• 3)- Nocardia which cause nocardiosis and
  mycetoma.
• 4)- Streptomyces which cause mycetoma.

4

GENUS OXYGEN GRANULE ACIDFAST
Actinomyces ANAEROBE YES no
Nocardia aerobe sometime PARTIALLY
Streptomyces aerobe YES no
5
Actinomyces israelii

• It is normal flora in the oral cavity and GIT.
• After local trauma, it invades the tissues
  causing actinomycosis.
• Actinomycosis is a chronic granuloma that open
  with sinuses draining yellow granules called
  sulphur granules.
• Lesions may be cervico-facial, thoracic,
  abdominal and pelvic.

6
(No Transcript)
7
Sulphur granules
8
Cervico-facial actinomycosis
9
Laboratory diagnosis

• Sulphur granules are crushed between two slides
  and examined microscopically to see filamentous
  Gram positive branching bacilli.
• Culture on blood agar which is incubated
  anaerobically.

10
Treatment

• Prolonged administration of penicillin plus
  surgical drainage.

DO NOT FORGET
11
Nocardia asteroides

• Nocardia asteroides is found in the soil.
• Inhalation of this organism by an
  immunocompromised person causes nocardiosis.
• Nocardiosis is a chronic lung infection that may
  form abscesses and sinuses (mimic Tuberculosis).
• It may also spread to brain and kidney.

12
(No Transcript)
13
(No Transcript)
14
Laboratory diagnosis

• Sputum or pus is stained by
• Gram stain to see filamentous Gram positive
  branching bacilli.
• Modified Z.N. stain because nocardia resists
  decolorization by H2SO4 in a concentration of 0.5
  to 1 and appear acid fast.
• Culture is done on brain heart infusion agar
  which is incubated aerobically.

15
Treatment

• Trimethoprim-sulfamethoxazole for long period up
  to 1 year surgical drainage.

16
GOOD LUCK