Risk factors and microbiological characteristics of bacterial peritonitis in patients undergoing peritoneal dialysis.

BACKGROUND: Peritoneal dialysis–associated peritonitis (PDAP) is a major complication of chronic peritoneal dialysis (PD), contributing to hospitalization, technique failure, and mortality. Characterizing patient-level risk factors and local microbiological patterns is essential for prevention strategies and empiric therapy selection. METHODS: This retrospective study included adults on continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD) at a single center between January 2022 and December 2024. Episodes of bacterial peritonitis were defined using International Society for Peritoneal Dialysis (ISPD) criteria. Demographic data, comorbidities, laboratory parameters, and microbiological culture results were analyzed. Patients were stratified into a peritonitis group (n = 36) and a non-peritonitis group (n = 203). Risk factors were assessed by univariate analysis, with significant variables (p < 0.10) included in multivariate logistic regression. RESULTS: Gram-positive cocci predominated among PDAP episodes (61.1%), with coagulase-negative Staphylococcus (30.6%) and Staphylococcus aureus (13.9%) as the leading isolates. Gram-negative bacilli accounted for 30.6%, led by Escherichia coli and Klebsiella spp., while non-fermenters represented 8.4%. In an exploratory multivariate analysis, factors associated with PDAP at diagnosis included lower hemoglobin (OR 0.956, 95% CI 0.922–0.991), hypoalbuminemia (OR 0.868, 95% CI 0.793–0.950), higher white blood cell count (OR 1.331, 95% CI 1.102–1.607), higher neutrophil percentage (OR 1.064, 95% CI 1.025–1.105), and lower serum calcium (OR 0.137, 95% CI 0.021–0.879). Diabetes mellitus was not independently significant. CONCLUSIONS: PDAP in this cohort was primarily caused by gram-positive cocci. Exploratory analysis identified a cluster of parameters indicative of inflammation and nutritional status that were associated with peritonitis at diagnosis. Findings support tailored empiric antibiotic coverage and suggest that prevention bundles could consider incorporating nutritional and inflammatory optimization alongside standardized culture practices. CLINICAL TRIAL NUMBER: Not applicable.