1. ACTINOMYCETES & NOCARDIA
Dr Sathya Anandam

2. ACTINOMYCETES
Gram positve, non motile, non sporing, non capsulated filamentous bacteria
Thin bacteria with muramic acid cell wall.
Superficial resemblance to fungi due to branching filaments.
Related to Corynebacteria and mycobacteria

3. Includes genera:
- Actinomyces, Arachnia, Bifidobacterium
- Nocardia, Actinomadura, Streptomyces

4. ACTINOMYCES Soil saprophytes & commensals of oral cavity
Cause actinomycosis - a chronic granulomatous disease
Indurated swelling, suppuration and discharging of sulfur granules from sinuses.
Later stage leads to fibrosis & tissue destruction
Infection usually endogenous.
A.israelli is the MC cause.

5. The name refers to ray – like appearance of the organism in the granules( Actinomyces, meaning ray fungus)
Mode of infection: mostly endogenous & trauma e.g. dental extraction

6. Worldwide in distribution
More common in rural areas and agricultural workers
Young males yrs age group more common.
Pelvic infection seen in women using intrauterine devices.
Organism occurs as commensal in mouth, URT and female genital tract.
Have low virulence

7. Pathogenesis
Enters the tissue, and bridges the mucosal or epithelial surface
Creates an anaerobic environment
Induces mixed inflammatory response
Forms painless indurated swelling with sinuses which may drain pus containing granules to the skin surface
Infection spreads to neighbouring organs with bone destruction

8. Clinical manifestations
4 clinical forms;
1. cervicofacial- lumpy jaw
2. Thoracic
3. Abdominal
4. Pelvic
Disseminated form- hematogenous spread
Also associated with inflammatory disease of gums.
Can also present as mycetoma
The disease is characterised by presence of Sulfur granules in the exudate

9. Laboratory diagnosis Specimen- pus, sputum, BAL,biopsy
Gross examination of granules
Microscopy: pus discharge is washed thoroughly in saline in a test tube
Sediment is collected which is crushed between two slides and smears are made

10. Gram’s staining: shows a central mass of Gram positive filamentous bacilli, radiating peripherally with hyaline, club- shaped ends
Granules are hard and non emulsifiable
Fluorescent antibody techniques
Fluorescent in situ hybridization

12. Histopathological staining: H & E stain/ Gomori’s stain on tissue sections reveal
Granules composed of eosinophilic clubs surrounding basophilic filaments and inflammatory cells such as neutrophils & macrophages- sun ray appearance

13. Sulfur granules are white to yellow with siz ranging from minute specks to about 5mm and are found only in tissue.

14. Isolation in culture- granules are washed and cultured anaerobically at 370C on BHIA and Thioglycollate broth.
A. israelli- small spidery colonies which become heaped up, white irregular or smooth and large in 10 days, on thioglycollate btoth fluffy balls at the bottom of tube
Species identification

15. TREATMENT
MEDICAL TREATMENT- prolonged treatment with penicillin or tetracycline for 6-12 months to prevent relapse
SURGICAL TREATMENT- drainage or excision

16. NOCARDIA Gram positive branching filamentous bacilli
Aerobic and acid fast
PRESENT IN SOIL
Infection exogenous
Species associated N.asteroides, N. Brasiliensis and N. caviae

17. Pathogenesis Worldwide, common in adult males
Inhalation of fragmented bacterial mycelia- pulmonary nocardia
Transcutaneous inoculation of bacteria- cutaneous/ sub cutaneous e.g mycetoma
Characteristic histological feature is an abscess with extensive neutrophilic infiltration & necrosis surrounded by granulation tissue

18. Risk factors
Opportunistic pathogen In immunocompromised host

19. NOCARDIA May be cutaneous, subcutaneous or systemic lesions in humans
Pulmonary form is MC
Occurs by inhalation of bacilli
Common cause of pneumonia in immunocompromised hosts
Disseminated nocardiosis- brain abscess
Actinomycetoma: chronic granulomatous subcutaneous infection

20. LABORATORY DIAGNOSIS Specimen: sputum, pus
Macroscopic examination of pus
Granules are soft
Microscopy by Gram and ZN stain(1% H2SO4)
Isolation done on routine media.
Colonies are dry to chalky, yellowish.

22. Histopathological examination shows multilobulated with sun ray appearance

24. TREATMENT MEDICAL Rx- sulfa drugs like TMP-SMX
SURGICAL Rx- drainage of abscess