Treatment of Nontuberculous Mycobacteria (NTM) Peritonitis
Diagnosis and Initial Management
The recommended treatment for NTM peritonitis requires a combination antimicrobial regimen based on susceptibility testing, catheter removal in most cases, and treatment for at least 12 months after culture conversion. 1
Diagnostic Approach
Obtain peritoneal fluid for:
- Acid-fast bacilli (AFB) smear
- Culture using both solid and liquid media
- Incubate cultures for minimum 6 weeks
- Process samples within 24 hours (refrigerate if delay anticipated) 1
Consider NTM infection when:
- Culture-negative peritonitis persists despite standard antibiotics
- Diphtheroids or Corynebacterium species are isolated
- Previous antibiotic exposure with refractory infection 2
Treatment Regimen
Core Antimicrobial Therapy
- Base treatment on susceptibility testing for macrolides, amikacin, and species-specific drugs 1
- Standard core regimen:
- Daily oral macrolide (preferably azithromycin)
- Rifampin
- Ethambutol 1
For Severe Infection (Intensive Phase: 3-12 weeks)
- Daily oral macrolide
- Intravenous amikacin (for initial 2-3 months)
- One or more of:
- Intravenous tigecycline
- Imipenem
- Cefoxitin 1
Catheter Management
- Catheter removal is required in approximately 90% of NTM peritonitis cases 3, 2, 4
- Early catheter removal is associated with better outcomes and may prevent progression from exit-site infection to peritonitis 3
Monitoring and Duration
- Obtain cultures every 4-8 weeks to assess microbiological response 1
- Continue treatment for at least 12 months after culture conversion 1
- Monitor for drug toxicity:
- Hearing loss (amikacin)
- Visual loss (ethambutol)
- Renal impairment
- Liver function abnormalities 1
Special Considerations
Antimicrobial Resistance Patterns
- M. fortuitum and M. chelonae are common causative species 4
- High resistance rates to:
- Fluoroquinolones (59.3%)
- Cefoxitin (73.1%)
- Most isolates remain sensitive to amikacin 4
Novel Treatments
- Clofazimine has emerged as a potentially effective adjuvant therapy, particularly for M. abscessus infections 5
Important Caveats
- Never use monotherapy with a macrolide or any single antimicrobial agent due to high risk of resistance development 1
- Consult with experts in NTM treatment for complex cases 1
- Delayed diagnosis is common and associated with poorer outcomes 4
- Mortality rates of approximately 12-14% have been reported 3, 4
- Most patients (63-92%) require permanent transition to hemodialysis 3, 2