Clinical Risk Factors and Outcomes of Carbapenem-Resistant Pseudomonas aeruginosa Nosocomial Infections in a Tertiary Hospital in China: A Retrospective Study from 2016 to 2023

Purpose: The global spread of carbapenem-resistant Pseudomonas aeruginosa (CRPA) represents a growing concern for public health, but long-term data from general tertiary hospitals in China are limited. This study aimed to identify risk factors for nosocomial CRPA infection and to evaluate their impact on in-hospital mortality. Methods: A retrospective case-control study of patients with Pseudomonas aeruginosa ( P. aeruginosa ) infections was conducted at Putuo Hospital from January 2016 to December 2023. A total of 208 CRPA clinical isolates were collected in the 8-year study. The control group was randomly selected at a ratio of 1:1 from patients with carbapenem-susceptible P. aeruginosa (CSPA) infection from the same period (within 2 weeks) and department (416 patients). The clinical characteristics of the inpatients were reviewed using the hospital information system. Univariate and multivariate analyses were performed to evaluate the risk factors associated with the development of CRPA infections. Results: The significant risk factors for CRPA infection were hypoproteinemia (OR=4.285, p < 0.001), admission to the intensive care unit (OR=2.143, p = 0.034), respiratory disease (OR=3.412, p < 0.001), nasogastric tube (OR =2.461, p = 0.007), hemoglobin < 90 g/L (OR =2.453, p = 0.004), previous antibiotic exposure to carbapenems (OR =5.580, p < 0.001), and co-infection with Klebsiella pneumoniae (OR=4.318, p < 0.001) and fungi (OR=4.781, p = 0.004). Within CRPA group, the in-hospital mortality rate was 30.3%, and cerebrovascular disease (OR=1.818, p = 0.003), carbapenem exposure (OR=2.625, p = 0.006), and mechanical ventilation (OR=2.157, p = 0.02) were independent risk factors for in-hospital mortality in patients with CRPA infections. Conclusion: Our findings help identify patients at high risk for CRPA infection and underscore the importance of antimicrobial stewardship and infection control measures in hospital settings. Keywords: carbapenem-resistant Pseudomonas aeruginosa , risk factors, nosocomial infection, antimicrobial resistance