Empiric Antibiotic Therapy for Peritoneal Dialysis-Related Peritonitis
The recommended empiric antibiotic regimen for peritoneal dialysis (PD)-related peritonitis is intraperitoneal (IP) vancomycin 1g every 5 days plus IP ceftazidime 1g daily, administered via the dialysate. 1, 2
Initial Empiric Regimen
Gram-positive coverage:
- Vancomycin 1g IP every 5 days is the preferred agent over cefazolin due to superior complete cure rates and coverage of methicillin-resistant organisms 2, 3
- Cefazolin should be avoided as first-line therapy in many centers due to poor sensitivity to coagulase-negative staphylococci (only 11% sensitivity to Staphylococcus epidermidis in recent data) 4
Gram-negative coverage:
- Ceftazidime 1g IP daily provides optimal coverage for gram-negative organisms including Pseudomonas species 5, 2
- Alternative: Oral moxifloxacin 400mg daily has demonstrated equivalent efficacy (78% vs 80% complete resolution) with better tolerability and ease of administration 6
Route of Administration
IP administration is superior to IV administration for treating PD-associated peritonitis, with significantly lower treatment failure rates (RR 3.52,95% CI 1.26 to 9.81) 3. The IP route achieves higher local concentrations at the site of infection while minimizing systemic toxicity 2.
Dosing Considerations
For ceftazidime IP administration:
- Loading dose: 1g in dialysate
- Maintenance: 1g daily in one exchange 5
- Can be incorporated into dialysis fluid at 250mg per 2L of dialysate for continuous ambulatory PD 5
For vancomycin IP administration:
Treatment Duration
Standard treatment duration is 14-21 days depending on organism and clinical response 3. Continue therapy for at least 2 days after signs and symptoms resolve 5. For relapsing peritonitis, 21-day courses may be considered, though evidence for benefit is uncertain 3.
Critical Pitfalls to Avoid
Do not use aminoglycosides as first-line therapy despite older recommendations. Aminoglycosides cause greater decreases in residual kidney function compared to less nephrotoxic alternatives, which directly impacts mortality and quality of life in PD patients 7. They also lack anaerobic coverage and require combination therapy 7.
Do not use cefazolin as empiric gram-positive coverage in centers with high rates of coagulase-negative staphylococcal resistance (>20%), as treatment failure rates will be unacceptably high 4.
Avoid IV administration when IP route is feasible, as IV antibiotics have significantly higher treatment failure rates 3.
Reassessment and De-escalation
Reassess at 48-72 hours when culture results become available 8. If gram-positive organisms are confirmed, discontinue gram-negative coverage. If gram-negative organisms are identified, narrow therapy based on susceptibilities 8, 7. For culture-negative peritonitis with clinical improvement, continue empiric dual coverage for full treatment course 3.
For treatment failure at 72 hours (persistent cloudy effluent, fever, abdominal pain), consider catheter removal, imaging for undrained collections, or resistant organisms including fungi 8, 6.
Special Situations
For relapsing or persistent peritonitis: Simultaneous catheter removal and replacement is superior to urokinase therapy (RR 2.35,95% CI 1.13 to 4.91) 3.
For fungal peritonitis: Immediate catheter removal is mandatory, as medical therapy alone has unacceptably high failure rates 8.