What is the treatment for Mycobacterium (mycobacterium) infections?

Treatment of Mycobacterium Infections

Treatment of mycobacterial infections requires multiple antimicrobial agents for extended periods, with regimens tailored to the specific mycobacterial species and site of infection. 1

Types of Mycobacterial Infections

Tuberculosis (M. tuberculosis)

• First-line treatment includes:
  • Isoniazid
  • Rifampin
  • Pyrazinamide
  • Ethambutol or streptomycin as a fourth drug 2, 3
• Treatment duration: Typically 6-9 months
• The fourth drug (ethambutol or streptomycin) should be included unless the likelihood of drug resistance is very low 2
• Reassess need for fourth drug when susceptibility results are available

Non-Tuberculous Mycobacteria (NTM)

M. avium Complex (MAC)

• Treatment regimen:
  • Clarithromycin (500 mg twice daily) or azithromycin as the cornerstone of therapy 1, 4
  • Ethambutol (15 mg/kg daily) 1
  • Additional agents may include rifampin, rifabutin, or amikacin based on susceptibility 1
• Treatment duration: At least 12 months after culture conversion 1
• For HIV patients with disseminated MAC:
  • At least two agents, including a macrolide (clarithromycin/azithromycin) 1
  • Ethambutol as preferred second drug 1
  • Consider adding clofazimine, rifabutin, rifampin, ciprofloxacin, or amikacin 1
  • Lifetime therapy if clinical and microbiologic improvement is observed 1

M. kansasii

• Treatment regimen:
  • Rifampin (600 mg daily)
  • Ethambutol (15 mg/kg daily)
  • Isoniazid (300 mg daily) 1
• Treatment duration: 12 months after culture conversion 1

M. malmoense and M. xenopi

• Treatment regimen:
  • Rifampin (450-600 mg daily)
  • Ethambutol (15 mg/kg daily)
  • Clarithromycin (500 mg twice daily) 1
• Treatment duration: 24 months 1

Rapidly Growing Mycobacteria (M. chelonae, M. fortuitum, M. abscessus)

• Treatment regimen:
  • Clarithromycin (500 mg twice daily)
  • Ciprofloxacin (750 mg twice daily)
  • Consider adding aminoglycoside or imipenem 1, 5
• Treatment duration:
  • Skin/soft tissue infections: 4-6 months 5
  • Bone infections: At least 6 months 5
  • Pulmonary disease: Up to 2 years if response is suboptimal 1, 5
• Surgical debridement is essential when possible 5
• Complete removal of infected foreign bodies is crucial 5

M. marinum (Fish Tank Granuloma)

• Treatment options:
  • Cotrimoxazole, or
  • Tetracycline, or
  • Rifampin plus ethambutol 1
• Treatment duration: 6 months 1

M. ulcerans

• Wide surgical excision with skin grafting is the treatment of choice 1
• Early disease may respond to rifampin, ethambutol, and clarithromycin 1

Monitoring Treatment

1. Clinical monitoring:

   • Assess fever, weight loss, night sweats during initial weeks of therapy 1
   • Regular evaluation of wound healing for skin/soft tissue infections 5

2. Microbiological monitoring:

   • Monthly sputum cultures until conversion to negative for pulmonary disease 5
   • Blood cultures every 4 weeks during initial therapy for disseminated MAC 1

3. Response timeline:

   • Clinical improvement typically within 4-6 weeks of therapy 1
   • Microbiological clearance may take 4-12 weeks 1

Important Considerations

• Multiple isolates from non-sterile sites are needed to establish disease, whereas one positive culture from a sterile site with supportive histopathology is usually sufficient 1
• Person-to-person transmission of NTM is very rare; contact tracing is not necessary 1
• If a patient has been notified as having tuberculosis but is later found to have NTM, they should be de-notified and treatment adjusted accordingly 1
• Susceptibility testing should guide therapy, especially for rapidly growing mycobacteria 1, 5
• Cure may not be attainable in some cases, particularly with pulmonary disease caused by rapidly growing mycobacteria 1

Common Pitfalls to Avoid

• Inadequate treatment duration
• Monotherapy (always use at least two effective agents)
• Failure to remove foreign bodies when present
• Overlooking surgical intervention when indicated
• Not adjusting therapy based on susceptibility results
• Failing to recognize when NTM represents colonization versus true infection