section name header

Information

Similar to M. tuberculosis, NTM can be detected on acid-fast or fluorochrome smears of clinical samples and can be cultured on mycobacterial medium. Isolation of NTM from a clinical specimen may reflect colonization and requires an assessment of the organism's clinical significance.

Treatment: Infections with NTM

Since NTM disease evolves over a long period, it is rarely necessary to begin treatment on an emergency basis before identifying the infecting species.

  • MAC infection requires multidrug therapy with a macrolide (clarithromycin or azithromycin), ethambutol, and a rifamycin (rifampin or rifabutin). Therapy is prolonged, generally continuing for 12 months after culture conversion; typically, a course lasts for at least 18 months.
  • M. kansasii lung disease is similar to TB in many ways and is also effectively treated with isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg per day). Treatment should continue until cultures have been negative for at least 1 year.
  • Extrapulmonary disease due to rapidly growing NTM is often treated successfully with a macrolide and another drug (with the choice based on in vitro susceptibility). Pulmonary disease due to M. abscessus is difficult to cure and often requires repeated courses that include a macrolide along with an IV-administered agent such as amikacin, a carbapenem, cefoxitin, or tigecycline.
  • M. marinum infection is effectively treated with any combination of a macrolide, ethambutol, and a rifamycin for 1-2 months after clinical resolution of isolated soft-tissue disease; tendon and bone involvement may require longer courses in light of clinical evolution.
  • Treatment of infections caused by other NTM is less well defined, but macrolides and aminoglycosides are usually effective, with other agents added as indicated.

For a more detailed discussion, see Raviglione MC: Tuberculosis, Chap. 202, p. 1102; Gelber RH: Leprosy, Chap. 203, p. 1122; Holland SM: Nontuberculous Mycobacterial Infections, Chap. 204, p. 1128; and O'Donnell MR, Reddy D, Saukkonen JJ: Antimycobacterial Agents, Chap. 205e, in HPIM-19.

Outline

Section 7. Infectious Diseases