Stenotrophomonas maltophilia peritoneal dialysis-related peritonitis: A 20-year single-centre retrospective review

Background Peritoneal dialysis (PD)-related peritonitis due to Stenotrophomonas maltophilia presents significant challenges in clinical management due to its multi-drug resistance and tendency to form biofilms. Published data on its clinical epidemiology and outcomes remain limited. Methods We retrospectively reviewed all S. maltophilia PD-peritonitis at a regional PD centre in Hong Kong from April 2005 to March 2025. Patient characteristics, antimicrobial sensitivity and resistance patterns, treatments, and outcomes were analysed. Results We identified 28 S. maltophilia peritonitis episodes in 27 patients during the study period, accounting for 0.96% of all peritonitis episodes. Nineteen (70.4%) patients had medical comorbidities suggesting immunocompromised states in addition to chronic kidney disease; most episodes occurred after hospitalization (64.3%) or antibiotic use (57.1%). While most initial isolates were susceptible to trimethoprim-sulfamethoxazole (100%), levofloxacin (96.3%), and minocycline (100%), later emergence of less susceptible isolates was common (42.9%). Six episodes (21.4%) achieved medical cure but 9 (32.1%) showed relapsing peritonitis. Fifteen (53.6%) experienced PD catheter removal while 12 (42.9%) required transfer to haemodialysis. Eight (28.6%) had peritonitis-associated death. Conclusion This is the largest case series of S. maltophilia PD-peritonitis to date. S. maltophilia was an uncommon cause of PD-peritonitis but conferred substantial adverse outcomes. Early identification of S. maltophilia and sufficient duration of appropriate antimicrobials may help achieve better outlook.