Risk Factors for Development and Mortality of Carbapenem-Resistant Pseudomonas aeruginosa Bloodstream Infection in a Chinese Teaching Hospital: A Seven-Year Retrospective Study.

Objective: Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative opportunistic pathogen, which can cause acute and chronic infections, often resulting in high mortality. The aim of this study was to investigate the risk factors for the development and mortality of patients with carbapenem-resistant P. aeruginosa bloodstream infection (CRPA BSI).

Methods: A total of 112 patients with CRPA BSI and 112 patients with carbapenem-sensitive P. aeruginosa (CSPA) BSI were included from a Chinese teaching hospital from January 2017 to December 2023 in this retrospective cohort study. The detection rate, antimicrobial susceptibility of P. aeruginosa and clinical characteristics of these patients were investigated. Multivariable logistic regression analysis was used to identify risk factors for the development and outcomes of CRPA BSI.

Results: In the past 7 years, 7480 blood samples of P. aeruginosa were cultured in the hospital. The detection rates of CRPA, multidrug resistant P. aeruginosa (MDRPA), and difficult-to-treat resistant P. aeruginosa (DTRPA) BSI increased annually (26% to 47%, 10% to 36% and 5% to 15%, respectively). CRPA showed high resistance to conventional antibiotics. Chronic lung disease (OR 3.953, 95% CI 1.131-13.812), transplantation (OR 2.837, 95% CI 1.036-7.770), multi-organ failure (OR 4.815, 95% CI 1.949-11.894), pre-infection within CRPA (OR 9.239, 95% CI 3.441-24.803), and exposure to carbapenems within 90 days (OR 2.734, 95% CI 1.052 -7.106) were independent risk factors for the development of CRPA bacteremia. Sepsis or septic shock (OR 8.774, 95% CI 3.140-24.515, p = 0.001) were independent risk factors of mortality.

Conclusion: Chronic lung disease, transplantation, multi-organ failure, prior CRPA infection, and prior carbapenems exposure are independent risk factors for the development of CRPA bacteremia. Sepsis or septic shock increases 28-day mortality. To investigate the molecular mechanisms of carbapenem-resistance of P. aeruginosa, standardize antibiotic usage, and assess risk factors for the development and mortality of CRPA BSI are beneficial to control infection and reduce death.