Timely diagnosis and management of Quambalaria cyanescens-induced peritoneal dialysis peritonitis: A rare case highlighting the role of galactomannan testing.

Fungal peritonitis in peritoneal dialysis (PD) presents significant challenges. We report the second Quambalaria cyanescens-related PD peritonitis in a 53-year-old male. Negative bacterial cultures and a positive galactomannan (GM) index in both PD effluent (PDE) (0.65) and serum (0.98) prompted early PD catheter removal on day 5. Molecular sequencing confirmed Q. cyanescens, with antifungal susceptibility testing revealing resistance to azoles and echinocandins but susceptibility to amphotericin B and isavuconazonium. Treatment with amphotericin B and voriconazole resolved symptoms, with no relapses during a two-year follow-up. This case highlights GM testing's critical role in guiding catheter removal and adherence to the 2022 ISPD Peritonitis Guidelines, ensuring favorable outcomes for rare fungal PD infections.