A case of Moesziomyces antarcticus peritonitis in a patient undergoing peritoneal dialysis

Background Fungal peritonitis is a common and serious complication associated with peritoneal dialysis (PD), and it is often refractory to treatment. Case presentation A 70-year-old patient undergoing peritoneal dialysis was admitted to our hospital with fever and cloudy PD fluid. A diagnosis of yeast-like fungal peritonitis was made by examining the PD fluid. After starting intravenous caspofungin acetate, the PD catheter was removed. A fungal pathogen was isolated from the peritoneal fluid and identified as Cryptococcus sp. Based on the results of antifungal susceptibility testing, the treatment was changed to oral voriconazole and continued for 6 weeks. However, because of the discrepancy between the morphological findings and culture results, we performed genetic analysis, which uncovered Moesziomyces antarcticus . This patient was diagnosed with PD-related peritonitis caused by M. antarcticus and was successfully treated with voriconazole and removal of the PD catheter. Conclusions Reports of human infection by M. antarcticus are rare, and only two cases have been recognized. This may be the first case of infection detected in PD fluid.