Genomic Features and Risk Factors of Carbapenem-Resistant Pseudomonas aeruginosa Bloodstream Infections

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) bloodstream infection is associated with high mortality and limited treatment options. This retrospective cohort study was conducted at a single Chinese hospital from January 2020 to January 2026 and included adult patients with P. aeruginosa bloodstream infection. Clinical data were extracted from the hospital information system, and whole-genome sequencing was performed on 48 CRPA isolates to determine multilocus sequence types, carbapenemase genes, and capsular serotypes. Univariate and multivariable logistic regression were used to identify factors associated with CRPA acquisition. Among 110 patients, 48 (43.6%) had CRPA bloodstream infection. Prior ICU stay within 1 month (adjusted OR = 5.67, 95% CI: 2.81-11.45, p < 0.001) and prior carbapenem exposure within 30 days (adjusted OR = 3.89, 95% CI: 1.92-7.88, p < 0.001) were independent risk factors for CRPA acquisition. ST-3757 was the predominant sequence type (39/48, 81.3%), KPC-2 was the predominant carbapenemase gene (32/48, 66.7%), and O11 was the most frequent serotype (12/48, 25.0%). All ST-3757 isolates shared pairwise average nucleotide identity above 98.5%, and phylogenetic analysis placed them in a single well-supported clade. These findings indicate that prior healthcare exposure and carbapenem use drive CRPA bloodstream infection in this setting and that an ST-3757-O11-KPC-2 lineage is locally epidemic, supporting targeted antimicrobial stewardship and genomic surveillance.