What is the recommended treatment for Nontuberculous Mycobacteria (NTM) peritonitis?

Treatment of Nontuberculous Mycobacteria (NTM) Peritonitis

NTM peritonitis requires catheter removal, drainage of fluid collections, and a multidrug antimicrobial regimen tailored to the specific mycobacterial species for at least 12 months after culture conversion. While specific guidelines for NTM peritonitis are limited, treatment principles can be derived from pulmonary NTM guidelines and peritonitis case reports.

Diagnostic Approach

• Consider NTM in cases of:

  • Culture-negative peritonitis
  • Refractory peritonitis not responding to conventional antibiotics
  • Isolation of diphtheroids or Corynebacterium species (may be misidentified NTM) 1
  • Previous antibiotic exposure without resolution 1

• Diagnostic testing:

  • Obtain peritoneal fluid for acid-fast bacilli (AFB) smear
  • Culture peritoneal fluid using both solid and liquid media
  • Incubate cultures for minimum of 6 weeks 2
  • Process samples within 24 hours; refrigerate if delay anticipated 2
  • Perform molecular identification of isolates to species level 2

Treatment Algorithm

1. Initial Management

• Catheter removal - Required in >90% of NTM peritonitis cases 3
• Drainage of any fluid collections 4
• Obtain susceptibility testing for:
  • Macrolides (clarithromycin/azithromycin)
  • Amikacin
  • Additional drugs based on species 2

2. Antimicrobial Therapy Based on Species

For M. avium complex (MAC):

• Core regimen:
  • Daily oral macrolide (preferably azithromycin over clarithromycin) 2
  • Rifampin
  • Ethambutol 5
• Add for severe infection:
  • Parenteral amikacin for initial 2-3 months 2, 5

For M. abscessus complex:

• Intensive phase (3-12 weeks):

  • Daily oral macrolide (preferably azithromycin)
  • Intravenous amikacin
  • Plus one or more: intravenous tigecycline, imipenem, or cefoxitin 2
  • Consider clofazimine as adjunctive therapy 6

• Continuation phase:

  • Daily oral macrolide
  • Inhaled amikacin
  • Plus 2-3 of: minocycline, clofazimine, moxifloxacin, or linezolid 2, 5

For other NTM species:

• Base treatment on susceptibility testing
• Consult with experts in NTM treatment 2

3. Treatment Duration and Monitoring

• Treat for at least 12 months after culture conversion 5
• Monitor for drug toxicity:
  • Hearing loss, visual loss (with ethambutol, amikacin)
  • Renal impairment (with amikacin)
  • Liver function abnormalities (with rifampin, macrolides) 2
• Obtain cultures every 4-8 weeks to assess microbiological response 2

Important Considerations

• Never use monotherapy with a macrolide or any single antimicrobial agent due to high risk of resistance development 2
• Therapeutic drug monitoring should be considered for:
  • Patients failing to improve despite appropriate regimen
  • Those on medications with significant drug interactions 2
• When using parenteral amikacin, monitor serum levels to minimize ototoxicity and nephrotoxicity 2
• Outcomes:
  • Catheter removal required in >90% of cases
  • Permanent transition to hemodialysis needed in ~63% of cases
  • Mortality rate approximately 12-14% 3, 1

Prevention of NTM Peritonitis

• For patients with NTM exit site infections:
  • Aggressive treatment with appropriate antimicrobials
  • Consider catheter removal (required in ~50% of cases)
  • Early intervention may prevent progression to peritonitis 3

The complexity of NTM peritonitis necessitates collaboration with infectious disease specialists experienced in NTM treatment, as drug intolerance and toxicity are common and may require regimen adjustments 2.