Clinical Characteristics, Risk Factors and Prognosis of Carbapenem-Resistant Pseudomonas aeruginosa Bloodstream Infections in Cancer Patients: An 8-year Retrospective Study in a Tertiary Cancer Hospital.

To ascertain clinical characteristics, risk factors and prognosis of bloodstream infection (BSI) caused by carbapenem-resistant Pseudomonas aeruginosa (CRPA) among cancer patients with solid tumors (ST) and hematological malignancies (HM). A retrospective study (January 2015 to December 2023) was performed on the health records of cancer patients with Pseudomonas aeruginosa (PA) BSI at a tertiary cancer hospital in China. Ninety-two CRPA BSI cases were randomly paired with contemporaneous carbapenem-sensitive Pseudomonas aeruginosa (CSPA) BSI cases at a ratio of 1:1. Multivariate logistic regression analysis was performed to identify risk factors associated with the development of CRPA BSI and Cox regression for mortality rates. Survival probability was evaluated using the Kaplan-Meier estimator. Between-group survival differences were analyzed using the Log rank test and Hazard ratios (HR) were calculated to quantify mortality risk disparities. A total of 361 cancer patients with PA BSI were included, 25.5% (92/361) of which were infected with CRPA. Among the 184 enrolled patients (48 with ST, 136 with HM), the independent risk factors for developing CRPA BSI were platelet counts and recent carbapenem use within 90 days in patients with ST. Presence of multidrug-resistant P. aeruginosa (MDRPA) and exposure to carbapenems within 90 days were the risk factors for developing CRPA BSI in patients with HM. The 30-day mortality of CRPA BSI was 37.5% and 35.3% in patients with ST and HM, respectively. Additionally, higher Pitt bacteremia score (PBS) was distinctly associated with increased 30-day mortality in cancer patients suffering from CRPA BSI (HR 1.672, 95% CI 1.309-2.135, p< 0.001). The mortality rates of CRPA BSI are notably high in both patients with ST and HM. The risk factors for CRPA BSI and mortality may guide and optimize the management of CRPA BSI in cancer patients.