Actinomycoses and Nocardia Infections

Actinomycoses and Nocardia Infections

 

Actinomycosis and nocardiosis are often considered when patients develop granulomatous diseases.

Epidemiology

  • Incidence
    • Actinomycosis – 1-2/300,000
    • Nocardiosis – <1/300,000
  • Age
    • Actinomycosis – peak 40-60 years
    • Nocardiosis – all ages
  • Sex
    • Actinomycosis – M>F
    • Nocardiosis – M:F;3:1
  • Transmission
    • Actinomycosis
      • Mucosal barrier disruption with contiguous spread
      • Inhalation of aspirated material
    • Nocardiosis – inhalation or direct inoculation (eg, penetrating injury)

Organisms

  • Actinomyces
    • Actinomyces is a facultative anaerobe
      • Gram-positive
      • Non-spore forming
      • Commensal of the human oropharynx gastrointestinal tract and female genitalia
    • Disease mainly caused by A. israelii
      • Infection may be associated with IUD use
    • Most infections are polymicrobial
  • Nocardia
    • Genus of aerobic actinomycetes
    • Aerobic, gram-positive
    • Weakly acid-fast
    • Soil saprophytes
    • Disease mainly caused by N. asteroides complex

Risk Factors

  • Actinomycosis
    • Alcoholism
    • Poor oral hygiene
    • Pulmonary form – emphysema, chronic bronchitis, bronchiectasis
  • Nocardiosis
    • Alcoholism
    • Diabetes mellitus
    • HIV
    • Immunocompromised state – particularly solid organ transplant patients
    • Trauma

Clinical Presentation

  • Actinomyces
    • Most frequent location – oral-cervicofacial
      • Soft tissue swelling, abscess or mass lesion
      • Most common in premandibular region
      • Sinus tracts occur frequently
    • Thoracic disease
      • Slowly progressive pneumonia
    • Abdominal disease
      • Appendicitis, perirectal disease, hepatitis, pelvic disease
  • Nocardia
    • Predominantly causes pneumonia
      • Irregular nodular disease
      • May progress to cavities
    • Disseminated disease commonly occurs
      • Cerebral abscesses occur in approximately 30% of patients with pulmonary disease
    • Skin and soft tissue infections, lymphadentitis
      • Usually resulting from trauma
    • Bacteremia 
      • Often catheter-related
    • Peritonitis
      • Usually peritoneal dialysis catheter related

See Also