Micrococcus aloeverae - A rare cause of peritoneal dialysis-related peritonitis confirmed by 16s rRNA gene sequencing

Abstract

The number of patients receiving peritoneal dialysis has increased worldwide. Herein, we report the first case to our knowledge of continuous ambulatory peritoneal dialysis (CAPD) peritonitis caused by Micrococcus aloeverae, which was initially reported to be caused by Micrococcus luteus in the dialysate culture report but later identified by 16S ribosomal ribonucleic acid (rRNA) gene sequencing as M. aloeverae. A 59-year-old woman visited the emergency room due to abdominal pain. She was hospitalized with CAPD peritonitis. The patient initially responded to empirical antibiotic treatment comprising intraperitoneal cefazolin (15 mg/kg/day) and ceftazidime (1 g/day); however, the leukocyte count of dialysate effluent increased again. M. luteus was isolated four times from peritoneal dialysate cultures. We treated the patient with intraperitoneal administration of vancomycin (2 g loading, followed by 1 g every 7 days) but needed to switch from CAPD to temporary hemodialysis. We analyzed the 16S rRNA sequence to confirm the exact causative organism, and the results revealed that the organism was M. aloeverae. Because M. aloeverae and M. luteus have sequence similarity, 16S rRNA sequencing is a useful method to distingush them.