NORCARDIA

1. General

   1. Weakly gram+

   2. Partially acid fast

   3. Soil bacteria

   4. Strict aerobic bacilli

   5. Non-motile

   6. Non-spore forming- from branched hyphae in tissue culture

   7. Catalase +

   8. Carbs used oxidatively

   9. Non-selective media with 5-10% CO2, slow growth

   10. Sputum, infected tissues, or abscesses may have filament that are seen by acid-fast stain

2. Pathogenesis

   1. Inhalation-> colonization of oropharynx-> aspiration of oral secretions into lower airways

   2. Trauma subcutaneously. Injection can lead to abscess and necrosis

3. Clinical syndromes

   1. Most common cause of acute or chronic suppurative infections

   2. Bronchopulmonary Infections

      1. Cough, dyspnea, and fever

      2. Cavitation and spread to plura

      3. Dissemination to CNS (brain abscess) or skin

   3. Cutaneous infections

      1. Primary infections: cellulitis, pustules, Pyoderma, abscesses, mycetomas- painless, chronic infx

         1. Localized subcu swelling, suppuration, many sinus tracts open to skin

         2. Infect connective tissue, muscle, and bone

      2. Secondary spread

   4. Lymphocutaneous

      1. Regional lymph nodes

      2. Cutaneous involvement along lymphatics

   5. Ocular infections

      1. Opportunistic

      2. Unclean contact lenses or ophthalmologic manipulation

4. Epidemiology

   1. Exogenous infection- inhalation, trauma, or opportunistic

   2. Immunocompromised- higher risk

      1. Chronic pulmonary disease- bronchitis, emphysema, bronchiectasis, alveolar proteinosis

      2. Skin wounds

      3. T-cell deficiencies or immunosuppressive therapy.

   3. Ubiquitous- everywhere

5. Treatment

   1. Long term- sulfonamide with surgery

   2. Proper wound care

6. Clinically Relevant Species

   1. N. asterides-

      1. 90% Norcardia infections, world-wide

      2. Bronchopulmonary disease

      3. 1/3 involve CNS

   2. N. brasiliensis (mycetomas) N. otitidiscaviarum

      1. Primary Cutaneous infection

   3. N. farcinica

Category: Microbiology Notes