Mycobacterium kansasii

Introduction

Causes HIV-associated mycobacterial infection.

Epidemiology

• more prevalent in patients form midwestern USA
• more prevalent in injection drug users
• environmental source: ? water, ? animals

Pathology

• cavitary pneumonia indistinguishable from tuberculosis
• disseminated infection
• extrapulmonary disease frequently involves the GI tract
  • infiltrative disease of the liver & small bowel
  • intra-abdominal lymphadenopathy

Clinical manifestations

• pulmonary infection resembles tuberculosis
  • cough, fever, weight loss

Laboratory

• CD4 count is generally < 200/mm3
• recovery & identification of organism in infected tissue & respiratory secretions
• Mycobacterium kansasii rRNA
• also see Mycobacterium

Management

• rifampin, ethambutol & isoniazid
• relatively resistant to isoniazid
• duration of therapy: 12 months or longer
• empiric antibiotic therapy for Mycobacterial infection in a patients with advanced HIV infection
  • isoniazid
  • rifampin
  • pyrazinamide
  • ethambutol
  • clarithromycin

More general terms

• Mycobacterium