What is the recommended treatment for Mycobacterium abscessus infections?

Treatment of Mycobacterium abscessus Infections

The recommended treatment for Mycobacterium abscessus infections requires a combination of multiple antibiotics including a macrolide (preferably azithromycin) with intravenous amikacin and one or more additional intravenous antibiotics (imipenem, cefoxitin, or tigecycline) for an initial intensive phase of 3-12 weeks, followed by a continuation phase with oral and inhaled antibiotics. 1

Initial Intensive Phase Treatment

For Pulmonary M. abscessus Infections:

• Initial intensive phase (3-12 weeks):
  • Intravenous amikacin (10-15 mg/kg/day for patients <50 years; 10 mg/kg/day for patients >50 years or when long-term therapy is anticipated) 1
  • Plus one or more of the following intravenous antibiotics:
    • Imipenem (500 mg 2-4 times daily) - preferred due to better tolerability 1
    • Cefoxitin (up to 12 g/day in divided doses) - high rate of adverse effects 1
    • Tigecycline - effective but often limited by nausea and vomiting 1
  • Plus oral macrolide (preferably azithromycin over clarithromycin, as it induces less erm gene resistance) 1

For Non-pulmonary M. abscessus Infections:

• Similar regimen as above but with better outcomes:
  • For serious disease: minimum 4 months of therapy 1
  • For bone infections: 6 months of therapy 1

Continuation Phase Treatment

• Oral macrolide (azithromycin preferred)
• Inhaled amikacin
• Plus 2-3 additional oral antibiotics from:
  • Minocycline
  • Clofazimine
  • Moxifloxacin
  • Linezolid 1

Treatment Duration and Monitoring

• For pulmonary disease: Treatment should continue for at least 12 months after sputum culture conversion 1, 2
• For non-pulmonary disease: 4-6 months depending on the site of infection 1
• Regular monitoring for adverse effects is essential:
  • Cefoxitin: Monitor for neutropenia (51%) and thrombocytopenia (6%) 3
  • Amikacin: Monitor for ototoxicity and nephrotoxicity 1
  • Linezolid: Monitor for anemia, peripheral neuropathy, and gastrointestinal effects 1

Treatment Outcomes and Expectations

• Pulmonary M. abscessus disease:

  • With current antibiotic options, M. abscessus pulmonary infection is often a chronic, incurable infection for most patients 1
  • Treatment success rates vary significantly:
    • 58-80.5% sputum conversion rates reported in studies using long-term parenteral antibiotics 3, 2
    • Significantly lower success rates (17%) in patients with clarithromycin-resistant isolates 3

• Non-pulmonary M. abscessus disease:

  • Better outcomes compared to pulmonary disease
  • Removal of foreign bodies (e.g., breast implants, catheters) is essential for recovery 1

Role of Surgery

• Surgical resection is strongly recommended for:
  • Focal lung disease in patients who can tolerate lung resection 1
  • Extensive disease or abscess formation 1
  • Cases where drug therapy is difficult 1
  • Surgery combined with antimicrobial therapy offers the best chance for cure 1

Alternative Treatment Approaches

• For patients who cannot tolerate standard regimens, consider:
  • Thrice-weekly amikacin dosing (25 mg/kg) - may be difficult to tolerate beyond 3 months 1
  • Inhaled amikacin in outpatient settings - shown to be effective and safe in some studies 4, 5
  • Newer drugs with potential activity:
    • Oxazolidinones (e.g., linezolid)
    • Glycylcyclines (e.g., tigecycline)
    • Ketolides (e.g., telithromycin) 1

Important Caveats

• Macrolide susceptibility testing is crucial - treatment success rates are significantly lower with resistant isolates 3
• Monotherapy with macrolides is not sufficient and may lead to resistance 1
• Expert consultation is recommended due to the complexity of treatment and common side effects 1
• Treatment regimens should be based on in vitro susceptibility testing whenever possible 1

The management of M. abscessus infections remains challenging with current antibiotic options. For pulmonary disease, the goal of therapy may need to be symptomatic improvement and disease regression rather than complete cure, while surgical intervention combined with antibiotics offers the best chance for cure in appropriate candidates.