Acute peritonitis due to Corynebacterium ulcerans in a patient receiving continuous ambulatory peritoneal dialysis: a case report and literature review

A 55-year-old Japanese woman receiving continuous ambulatory peritoneal dialysis (CAPD) was admitted to our service with abdominal pain and cloudy peritoneal fluid. Laboratory data revealed a white blood cell count of 7.20 × 10⁹ cells/L, hemoglobin 9.8 g/dl, hematocrit 29.0%, platelet count 284 × 10⁹ cells/L, and C-reactive protein (CRP) 0.109 g/L. Peritoneal fluid white blood cell count of 2,000 cells/µl suggested acute peritonitis. An empiric trial of cefazolin and ceftazidime, subsequently switched to meropenem, vancomycin, minocycline, and amikacin, did not improve the patient’s symptoms. The peritoneal fluid collected before initiation of antibiotic therapy grew Corynebacterium ulcerans. Ampicillin/sulbactam was started based on the culture and sensitivity data. On hospital day 8, the CAPD catheter was removed due to no clinical improvement and persistently increased levels of CRP to 0.0174 g/L. A 14-day course of ampicillin/sulbactam improved her clinical condition and laboratory data. Microbiological analysis revealed that C. ulcerans isolated from this patient did not produce diphtheria toxin. C. ulcerans was not isolated from her dog’s oral and nasal cavities during a search for the route of her infection. We recommend that in patients with peritoneal dialysis, special attention should be paid to Corynebacterium peritonitis, especially due to C. ulcerans, which may produce diphtheria toxin, be resistant to multiple antibiotics, and frequently become recurrent.