Serratia marcescens peritonitis in a continuous ambulatory peritoneal dialysis patient: A case report and literature review.

INTRODUCTION

Peritonitis caused by Serratia marcescens in patients undergoing continuous ambulatory peritoneal dialysis is a rare but clinically significant condition. As an opportunistic gram-negative pathogen with notable genomic plasticity and biofilm-forming capacity, Serratia marcescens frequently leads to catheter loss and treatment failure. This case highlights the diagnostic challenges, antibiotic management strategy, and the clinical course leading to catheter removal in a high-risk continuous ambulatory peritoneal dialysis patient.

CASE PRESENTATION: A 61-year-old woman with stage 5 chronic kidney disease on continuous ambulatory peritoneal dialysis for four years presented with abdominal pain, nausea, fever (38.3°C), and cloudy dialysate. Dialysate white blood cell count was markedly elevated at 5600/mm³ with neutrophil predominance. Peritonitis was diagnosed per International Society for Peritoneal Dialysis criteria. Peritoneal fluid culture grew Serratia marcescens susceptible to meropenem, piperacillin/tazobactam, ciprofloxacin, ceftazidime, imipenem, and trimethoprim-sulfamethoxazole, but resistant to amikacin, amoxicillin-clavulanate, and ampicillin. Empirical therapy with piperacillin/tazobactam and teicoplanin was replaced by intravenous plus intraperitoneal meropenem combined with teicoplanin. Despite a partial decrease in dialysate cell count, persistent fever and inadequate acute phase reactant response led to catheter removal after approximately 21 days of targeted therapy. Following catheter removal and 14 additional days of antibiotic treatment (35 days total), the patient recovered fully and was transitioned to hemodialysis.

CONCLUSION

This case underscores the aggressive nature of Serratia marcescens peritonitis in continuous ambulatory peritoneal dialysis patients and highlights the importance of prompt empirical antibiotic therapy, early culture-directed treatment escalation, and timely catheter removal decisions. Intraperitoneal plus intravenous meropenem represents a rational therapeutic strategy, yet catheter salvage may not always be achievable. Clinicians must maintain a high index of suspicion for catheter removal in refractory gram-negative peritonitis.