(589) The Clinical Outcomes of Carbapenem-Resistant Pseudomonas aeruginosa Treated With Sensitive β-Lactam

Introduction: Carbapenem-resistant P. aeruginosa (CRPA) is one of the three Critical Priority pathogens associated with increased length of stay (LOS) and mortality. There is scarce literature evaluating the treatment outcomes in patients with CRPA treated with sensitive antipseudomonal β-lactam agents. Thus, this study aimed to assess the efficacy of non-carbapenem β-lactam (NCBL) compared to Noval β-lactam (NBL) for managing CRPA.

Methods: A single-center retrospective study was conducted between January 2016 and December 2022; the study included adult patients ≥18 years with microbiological isolates of CRPA. Patients were treated based on the microbiology sensitivity with antipseudomonal or noval β-lactams for > 48 h and followed until discharge or death. Patients were excluded if isolates were not susceptible to any antipseudomonal β-lactam agents. The primary outcome was 30-day infection-related mortality. Secondary outcomes include clinical cure, microbiologic eradication, 90–day recurrence, 30-day readmission due to infection rate, intensive care unit (ICU), and hospital LOS.

Results: 138 patients were included: 111 in the NCBL group and 27 in the NBL group. The median age was 63.5 [45, 77] years, and 61.6% were male. 65.9% of included patients were critically ill, 68.5% vs. 55.6% in the NCBL and NBL groups, respectively. The Median APACHE II score was 18 [13, 23]. No statistical significance was found in 30-day mortality related to infection (27.9% vs. 40.7%; P= 0.19); clinical cure rate (47.7 vs. 59.3%; P = 0.28); 90 days recurrence of infection (59.5% vs. 40.7%; P = 0.07); median hospital LOS 77 [32,133] vs. 79[23,198]; P= 0.77) in NCBL and NBL groups, respectively. However, median ICU LOS (7 [4,11] vs. 389[29,749]; P= 0.041) and microbiological eradication rate (34.2% vs. 55.6%; P= 0.041) were higher in the NBL group. Moreover, 30-day readmission rates were higher in the NCBL group (15.3 vs. 0; P=0.03). The multivariable logistic model showed that vasopressor use and APACHE II score were associated with increased infection-related mortality at 30 days.

Conclusions: In patients with CRPA infections, there was no statistically significant difference in 30-day infection-related mortality among patients treated with sensitive antipseudomonal β-lactam agents compared with novel agents.