Successful treatment of peritoneal dialysis-related peritonitis caused by Dermacoccus nishinomiyaensis

A 53-year-old man receiving peritoneal dialysis (PD) for 4 months presented with PD-related peritonitis (abdominal pain, turbid peritoneal dialysate effluent, white blood cell in peritoneal dialysate effluent 5350/µL, C-reactive protein 25.56 mg/dL) caused by Dermacoccus (D.) nishinomiyaensis. He was first treated empirically with cefazolin and ceftazidime. After detection of D. nishinomiyaensis in the peritoneal effluent culture collected on the first day of hospitalization, the antibiotics were changed to amoxicillin and vancomycin. After confirming negative-conversion of peritoneal effluent culture, treatment was continued for more than 6 weeks. The peritonitis resolved; he continues peritoneal dialysis without withdrawal from PD or catheter removal. D. nishinomiyaensis is part of resident microbiota of the skin, and its pathogenicity is rarely reported. To date, there is no report of PD-related peritonitis caused by D. nishinomiyaensis. Because it is a slow grower, it may be missed and the peritonitis categorized as culture-negative. Long-term culture is important to detect it. It is difficult to determine the antibiotics that can be used because susceptibility to antibiotics is unknown due to the organism’s rarity. Furthermore, the appropriate treatment period is also unknown. Long-term treatment may be useful in PD-related peritonitis caused by D. nishinomiyaensis because it is a slow grower.