Serratia marcescens Peritonitis in a Diabetic Patient Receiving Continuous Ambulatory Peritoneal Dialysis
A 45-year-old male on CAPD with end-stage renal disease (ESRD) secondary to diabetes mellitus presented with abdominal pain and a dialysate WBC count of 9,070/mm3 (97% neutrophils). The patient had a history of hypertension and insulin-dependent diabetes mellitus for over 20 years, and had been maintained on CAPD since 2001. He had experienced two episodes of CAPD-associated peritonitis caused by coagulase-negative staphylococci 10 years earlier. He had not taken immunosuppressive drugs or steroids. The patient's blood sugar had been well controlled, and his hemoglobin A1c was 6.7%.\nA 50 mL sample of peritoneal fluid was centrifuged at 3,000 g for 15 minutes, followed by resuspension of the sediment in 5 ml of sterile saline and inoculation on solid culture medium. Immediately after sampling, the patient was treated empirically with intraperitoneal cefazolin (15 mg/kg/day) and ceftazidime (1 g/day). His body weight was 52.0 kg, his creatinine level was 10.0 mg/dL, and his urine output was < 100 mL/day. After 5 days of aerobic incubation on blood agar, the pathogenic organism was identified as S. marcescens. In vitro susceptibility, tested by the disk diffusion method, demonstrated that the organism was resistant to cefoxitin, imipenem, and ampicillin/sulbactam, but susceptible to gentamicin, ciprofloxacin, levofloxacin, and ceftazidime. At the same time, blood cultures that were performed were positive for an organism identified as S. marcescens via bacterial recombinant DNA sequencing. At this point, the patient's clinical symptoms and cloudy dialysate had not shown significant improvement. His peritoneal WBC count was 8,750/mm3 (98% neutrophils), and he continued to complain persistent abdominal distension and pain. On the basis of culture and antibiotic susceptibility results, cefazolin was discontinued and intraperitoneal gentamicin (40 mg/day) was started. Oral ciprofloxacin was also begun at a dose of 500 mg daily, which has been known to be effective in S. marcescens peritonitis []. Despite appropriate antibiotic therapy, however, the patient still complained of abdominal pain, and the peritoneal dialysate remained cloudy and continued to demonstrate a high WBC count, consisting mainly of neutrophils. The CAPD catheter was removed 10 days after the initiation of intraperitoneal antibiotic treatment. After removal of the catheter, the patient's abdominal pain was relieved and his C-reactive protein level decreased from 13.80 mg/dL to 8.07 mg/dL. His total hospital stay was 20 days, and oral ciprofloxacin was continuously prescribed for 10 days following removal of the CAPD catheter.