Actinomycetes and Nocardia

Actinomycetes and Nocardia

1. Actinomycetes & Nocardia DR ARUNA RANI BEHERA DEPARTMENT OF MICROBIOLOGY

2. Actinomycetes are thin bacteria that possess a cell wall containing muramic acid They have prokaryotic nuclei and are susceptible to antibiotics Superficially resemble fungi due to branching filaments Gram-positive, non-motile, non- sporing , noncapsulated filaments that break into bacillary or coccoid elements. Most are free-living in soil Actinomycetes

3. Anaerobic Actinomyces : Non-acid fast, anaerobic or microaerophilic - Arachnia , Bifidobacterium and Rothia Aerobic Nocardia : Aerobic, weakly acid fast - Nocardia , Actinomadura , Dermatophilus and Streptomyces - Streptomyces may cause disease but they are a major source of antibiotics Actinomycetes

4. Ray-like appearance of organisms in granules Chronic granulomatous infection in humans and animals Indurated swelling , mainly in connective tissues, with suppuration , discharge from multiple sinuses Discharge has yellowish, soft, waxy granules called s ulphur granules Endogenous infection Trauma, foreign body and poor oral hygiene may favour tissue invasion Actinomycosis

5. Actinomyces israelii is the most common causative agent of actinomycosis Four main clinical types are seen Cervicofacial Thoracic Abdominal Pelvic Actinomycosis

6. Cervicofacial actinomycosis : Most common form Painless, slow-growing, hard mass with cutaneous fistulas  lumpy jaw Indurated lesion on the cheek and submaxillary region

7. Thoracic: Lesions in the lung, may involve the pleura and pericardium, spreading outwards through the chest wall Abdominal: Lesion is usually around the cecum , involving neighbouring tissues and abdominal wall Pelvic: Associated with the use of intrauterine device (IUD), abscess in bone and soft tissues with chronic draining sinuses to the exterior Causes disease of gums( gingivitis, periodontitis )and sublingual plaques leading to root surface caries May present as mycetoma , treated with penicillin for several weeks

8. 1.Specimens - pus or tissues - pulmonary disease- sputum 2. Gross examination of granules- Pus washed in saline & sediment collected – Sulfur Granules : gritty, white or yellowish of <5 mm in size Granules crushed between two slides  smears ( white to yellow) 3.Direct microscopy: Dense network of thin Gram-positive filaments surrounded by peripheral zone of swollen, radiating, club-shaped structures presenting a sun ray appearance; the clubs are antigen–antibody complexes Laboratory Diagnosis of Actinomycosis

9. Culture 4.Isolation in culture : Sulphur granules or pus innoculated into thioglycollate liquid medium or streaked on brain–heart infusion agar Washed sulfur granules cultured anaerobically at 37°C Thioglycollate broth: A.israelii - fluffy balls at the bottom of the tube A.bovis - uniform turbidity ™ Brain heart infusion (BHI) agar: Small spidery colonies in 48–72 hours, becomes heaped up, white, irregular smooth large colonies in 10 days

10. Penicillin, tetracycline for months supplemented with surgery Treatment

11. Nocardia

12. Resembles Actinomycetes morphologically but it is aerobic Nocardia are Gram-positive and some species like N. asteroides and N. brasiliensis are acid fast Found in soil and infection is exogenous Causes cutaneous , subcutaneous and systemic lesions Common species are N. asteroides , N. brasiliensis and N. caviae Nocardia

13. Morphology: Filamentous, rod-shaped bacteria that do not produce spores, non-motile, catalase positive and weakly acid fast by Kinyoun’s acid fast staining method N. asteroides is most commonly involved in human disease Transmission is through contaminated soil and not from humans or animals

14. Clinical forms: Cutaneous: Local abscess, cellulitis or lymphocutaneous lesions, subcutaneous actinomycotic mycetoma Systemic : Manifests as pulmonary disease, pneumonia, lung abscess or resembles tuberculosis Metastatic manifestation : May involve the brain, kidneys and other organs Systemic nocardiosis occurs more often in immunodeficient persons

15. Laboratory Diagnosis of Nocardiosis 1.Direct microscopy Modified acid-fast staining( 1% sulfuric acid) Nocardiae are weakly acid fast Branching & filamentous acid-fast bacilli

16. 2.Isolation in culture : Grows on ordinary media forming dry, granular wrinkled colonies, producing pigment ranging from yellow to red Treatment: Resistant to penicillin; cotimoxazole and minocycline are used Surgery is performed to remove mycetomas In immunocompromised , amikacin and cefotaxime are used

17. Usually caused by Actinomyces israelii , A. bovis N. asteroides, N. brasiliensis, N. caviae Actinomadura madurae, A. pelletierii Streptomyces somaliensis Botryomycosis: Mycetoma-like lesion produced by Staphylococcus aureus and other pyogenic bacteria Mycetoma from Bacterial Causes

18. Mycetoma is a localised chronic granulomatous involvement of subcutaneous and deeper tissues affecting the foot and hand and presenting as swelling with multiple discharging sinuses First described by Gill 1842— maduramycosis Actinomycotic – granules are yellow or white , filaments are thin (1 µm) May be due to fungus, filaments are thicker (4–5 µm), granules are black Actinomycotic Mycetoma

19. Allergic alveolitis , hypersensitive pneumonitis and chronic pulmonary obstructive disease (COPD) May be caused by inhaled spores of thermophilic actinomycetes Framer’s Lung

20. Differences between Actinomyces & Nocardia Actinomyces Nocardia Acid-fastness Non Acid fast Partially acid fast O 2 requirement Anaerobe Obligate aerobe Habitat Found as oral flora Infections occur endogenously Usual habitat is soil Infections occur exogenously Risk factors Disease occurs in immunocompetent host also Usually affects people with low immunity

21. Differences between Actinomyces & Nocardia Actinomyces Nocardia Culture 1.Spidery molar teeth colony in solid media 2.Fluffy ball at bottom of the liquid medium Colonies are creamy, wrinkled and orange to pink. Recovery done by- 1.Selective media 2.Paraffin bait technique 3.LJ medium Drug of choice Penicillin Sulfonamide or Cotrimoxazole

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