[A case of Peritonitis Caused by Wickerhamomyces anomalus (Candida pelliculosa) Related to Peritoneal Dialysis].

Fungal peritonitis is less commonly seen than bacterial peritonitis in patients undergoing peritoneal dialysis (PD), but it is a serious complication with high morbidity and mortality. It often results in catheter loss and modifying therapy from PD to hemodialysis. The causative organisms are often Candida species. In this report, a PD-associated peritonitis caused by Wickerhamomyces anomalus (Candida pelliculosa), a rare fungal infection agent with increasing clinical importance by causing different clinical pictures was presented. An outpatient peritoneal fluid culture was sent from a 48-yearold male patient, who had been undergoing continuous peritoneal dialysis (CAPD) for 9 years, due to abdominal pain and blur in peritoneal fluid during dialysis. The patient admitted to the emergency department four days later due to the persistence of his complaints. A sample of peritoneal fluid was taken in the emergency department and sent to the laboratory for microbiological analysis. In the direct microscopical examination of the peritoneal fluid; cell number was determined as 210/mm3, and no microorganisms were seen in the Gram and methylene blue staining. The patient was admitted to the nephrology service with a pre-diagnosis of PD-associated peritonitis. Enterobacter aerogenes was grown in the peritoneal fluid culture which was sent from the dialysis outpatient clinic four days ago. The peritoneal fluid sample sent from the emergency department was inoculated on 5% sheep blood , EMB and chocolate agars and no growth was detected. As the patient's complaints and peritoneal fluid leukocyte count continued to increase, peritoneal fluid cultures were repeated and recurrent growth of yeast was detected in cultures. The yeast was identified as Candida pelliculosa by matrix assisted laser desorption ionization time-of-flight mass spectrofotometry (MALDI-TOF) VITEK®MS (bioMerieux, France). The species identification was confirmed by sequencing the target ITS gene regions on the rRNA and the isolate was identified as 100% Wickerhamomyces anomalus (sexual reproduction form of Candida pelliculosa, teleomorph). The reference microdilution method was performed according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI) in order to test the antifungal susceptibility. After 24 hour incubation, the minimal inhibitory concentrations (MIC) were determined as 0.03 μg/ml for amphotericin B, 0.125 μg/ml for caspofungin 0.125 μg/ml for voriconazole, 0.03 μg/ ml for itraconazole and 4 μg/ml for fluconazole. Fluconazole and anidulafungin were started for the treatment of fungal peritonitis. The patient's peritoneal dialysis catheter was removed and hemodialysis was applied to the patient. Clinical and laboratory symptoms regressed with antifungal therapy and the patient's anidulafungin treatment was discontinued for 14 days after the catheter removal. In conclusion, in patients undergoing CAPD, as in our case, fungal pathogens should also be considered although it is rare, when there is no laboratory and clinical improvement, and the response to treatment is not complete in PD-associated peritonitis to prevent delays in diagnosis and treatment.