This document discusses Actinomyces and Nocardia infections. Actinomyces israelii is normal flora that can cause actinomycosis, a chronic infection presenting with hard swellings that drain pus through sinuses. Diagnosis involves finding sulfur granules or filamentous bacteria on smears and cultures. Treatment is surgical drainage and penicillin. Nocardia species like N. asteroides are environmental bacteria that can cause pulmonary or skin infections. Diagnosis involves identifying thin, branching, weakly acid-fast filaments on smears and cultures. Treatment involves drainage and antibiotics like TMP-SMX.

1. Actinomyces and Nocardia

2. Objectives
To be familiar with
• The clinical infections associated with
Actinomycetes
• The clinical infection caused by Nocardia spp.
• The microscopic morphology and colonial
morphology of Nocardia and Actinomycetes
• Antimicrobial therapy

3. ACTINOMYCES ISRAELII
• Normal flora of mouth & female genital tract
• Opportunistic pathogen
Actinomyces israelii
Actinomyces Gerencseriae
Actinomyces odontolyticus
MORPHOLOGY & GROWTH
• Elongated branching Gram-positive bacilli
•Anaerobic or microaerophilic
•Temperature range 35-37oC
• Slow growth on blood agar in 4-7 days
DISEASE: Actinomycosis

4. ACTINOMYCOSIS
Source of infection
• Endogenous
Pathogenesis
• After local trauma, organisms invade tissues
• Due to low oxygen tension, organisms multiply
• Form hard yellow granules (called sulfur granules) which
are bacterial filaments solidified with tissue exudates
• These granules drain outside through sinuses

5. ACTINOMYCOSIS
Clinical Features
• A chronic infection
Cervicofacial Actinomycosis
• The most common form
• Develops due to poor dental hygiene & tooth
extraction. Appear as hard tender swelling
that drains pus through sinus tracts
• Multiple sinuses, scarring on neck &
submaxillary area
Thoracic & Abdominal Actinomycosis
• Are uncommon

6. ACTINOMYCOSIS
LAB DIGNOSIS
• Sulfur granules in pus specimen
Direct Gram-smear :
• Finely branching filamentous bacilli
Culture on
• Blood agar anaerobically for 4-7 days
• Molar tooth appearance
Histopathology
Treatment
• Surgical drainage
• Penicillin for 4-6 weeks

7. Nocardia spp.
• Strict aerobes.
• Infections caused by Nocardia Spp. can
occur in Immuno-compromised and immunocompetent individuals.
• N. asteriodes, N.brasiliensis are the major
causes of these infections
• Nocardia spp. can cause three types of skin
infections in immuno-competent individuals
1. Mycetoma (chronic, localized, painless,
subcutaneous infection)
2. Skin abscesses or cellulitis
3. Lymphocutaneous infections
• In Immuno-compromised individuals
Nocardia Spp. Can cause invasive pulmonary
infections and disseminated infections
(brain abscess )

8. NOCARDIA ASTEROIDES
(80%)
• Gram-positive thin branching filaments
• Weakly acid fast
• Aerobic
• Found in environment particularly in soil
• Disease : Nocardiosis
• Source of Infection : Soil (exogenous)

9. Nocardia asteriods ( Gram Stain)
Nocardia asteriods ( modified A F)

10. NOCARDIOSIS : CLINICAL FEATURES
Pulmonary Nocardiosis
• Due to inhalation of organism
• Pneumonia-like abscesses
• Usually in immunocompromised patients
Skin & Subcutaneous Tissue Infection
• Usually after trauma like thorne prick
• May present as sinus tract like
actinomycosis

11. NOCARDIOSIS
LAB DIAGNOSIS
Specimen : Sputum or pus
Staining with :
• Gram-stain or Weak Acid-Fast
Culture on:
• Blood agar
• LJ agar
TREATMENT
• Surgical drainage
• Trimethoprim-sulphamethoxazole