Abstract
Editor:
Fungal peritonitis is a rare but serious complication of continuous ambulatory peritoneal dialysis (CAPD) (1,2). We report a case of peritonitis due to Aureobasidium pullulans, a rare fungal pathogen, and review previous publications.
A 37-year-old Japanese male with end-stage renal failure due to chronic glomerulonephritis started CAPD via a double-cuffed Tenckhoff catheter in May 2006. He was using a double-bag system with manual connectology. In April 2007 he developed his first episode of peritonitis, presenting with a low grade fever, abdominal pain, and cloudy dialysate, and visited our outpatient department 2 weeks after the onset of his symptoms. Physical examination revealed abdominal rebound tenderness and muscular defense. Drained dialysate was cloudy with an elevated cell count of 1900 cells/mm3 (71% polymorphonuclear leukocytes, 6% lymphocytes, 3.5% eosinophils, and 19.5% unclassified cells). He was admitted to the hospital and empirical therapy for peritonitis with cefazolin and ceftazidime was started, but no improvement in clinical symptoms was observed. Two days later, his peritoneal fluid cultures grew black fungal colonies. We identified this fungus as the pathogen of the peritonitis, not as a contaminant, because these colonies were observed in two consecutive examinations. With the diagnosis of fungal peritonitis, the peritoneal catheter was removed immediately, as is recommended in a report on other fungal peritonitis (3), and antifungal therapy with flucytosine and fluconazole was commenced. After this therapeutic modification, the patient's clinical symptoms improved and his temperature gradually returned to normal. Two weeks later, we discontinued flucytosine and fluconazole because of the recurrence of a high fever, which, without aggravation of abdominal symptoms, was considered a side effect of the antifungal drugs. No recurrence of the peritonitis was observed. The patient recovered without any sequelae and is now on hemodialysis, his treatment of choice. The pathogen was subsequently identified by molecular diagnosis as Aureobasidium pullulans. As for the route of infection, contamination during CAPD bag exchange was highly suspected, as had been speculated in the other reported cases (Table 1). The patient performed frequent bag exchanges with insufficient attention to sanitary precautions in a house with old tatami mats, which, in humid weather, promote the growth of A. pullulans. Our patient was young, nondiabetic, and HIV negative and his dialysis quantity was adequate. We would like to emphasize that the opportunistic agent in this case, A. pullulans, may be contagious and cause peritonitis even in stable CAPD patients without a high risk of infection.
Reports of Aureobasidium pullulans Peritonitis
NA = not available; AMPH = amphotericin B; 5-FC = flucytosine; FLCZ = fluconazole; CAPD = continuous ambulatory peritoneal dialysis.
In Case 10, the peritonitis recurred after antifungal therapy, but the patient was successfully treated by catheter removal and a new course of antifungal therapy.
Current report.
Aureobasidium pullulans belongs to a group of dematiaceous fungi widely found in any humid environment: on leaves, in the soil, on wet paper, on painted walls. Initially it forms white, yeast-like mucoid colonies, becomes filamentous, and changes to dark brown and then to black as it matures. Hyphae and dark pigmentation are usually recognizable after several days. At this stage, diagnosis of A. pullulans by an expert is morphologically possible; however, molecular diagnosis is the definitive test to distinguish it from other types of dematiaceous fungi. It is frequently isolated as a skin contaminant but rarely causes cutaneous infection, and only a few cases of deep infection have been reported (8). Only 10 cases of CAPD-associated peritonitis due to A. pullulans have been published as of this writing (4-7). However, in the presence of clinical signs of infection, this fungus should be considered as the pathogen when it is isolated in multiple samples from otherwise sterile sites (8). Indeed, in one previous case report (Case 8), even though A. pullulans was considered the potential contaminant, antibacterial agents rather than antifungal agents were administered as the initial therapy (5) (Table 1).
No standard therapy has been developed for peritonitis caused by A. pullulans because clinical courses are available for only 3 of 10 reported cases (5-7), and each of these 3 cases was treated in a different way (Table 1). In our case, flucytosine and fluconazole were chosen because these agents have less toxicity than amphotericin B and achieve good penetration into the peritoneal fluid (7). Our patient recovered without sequelae with a 2-week course of antifungal therapy. We consider that the early start of antifungal medication and surgical removal of the catheter played a crucial role in this good outcome, because all three previous cases were treated successfully with peritoneal catheter removal (Table 1). In Case 10, peritonitis recurred after 8 weeks of antifungal therapy and was eventually cured by catheter removal and an additional course of antifungal medication (Table 1) (7). In addition, during prolonged therapy with catheter preservation, invasion of the fun- gus into the catheter was sometimes observed (6,7). Thus, it is strongly recommended that antifungal treatment be started early along with peritoneal catheter removal for CAPD peritonitis caused by Aureobasidium pullulans.
Footnotes
Acknowledgment
This case was presented at the 3rd Asian Chapter Meeting of the International Society for Peritoneal Dialysis, held in Hiroshima, Japan, 22 – 24 November 2007.