Risk factors associated with increased mortality in patients with Pseudomonas aeruginosa resistant to carbapenems but susceptible to other traditional antipseudomonal β-lactams Restricted; Files Only
Kim, Elizabeth (Spring 2025)
Abstract
Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) can cause healthcare-associated infections associated with poor outcomes. CRPA susceptible to at least one traditional antipseudomonal β-lactam (“S-CRPA”) is a unique phenotype with an unknown optimal treatment regimen. We aimed to study trends in S-CRPA treatments over time and to determine if S-CRPA treated with a newer β-lactam/β-lactamase inhibitor (BL/BLI) was associated with improved clinical outcomes compared to a traditional antipseudomonal β-lactams (TABL).
Methods: We retrospectively analyzed all incident S-CRPA cases in a four-hospital academic healthcare system in Atlanta, GA from 1/1/2013 to 9/30/2022. Patients receiving either a newer BL/BLI or a TABL for definitive antibiotic therapy, defined as having received at least 3 days of active therapy between 4-14 days after culture collection, were included. We plotted trends in antibiotics used for definitive treatment, specimen source, and β-lactam resistance in S-CRPA cases over the study period. Using univariable and multivariable log-binomial regression, we compared outcomes of in-hospital mortality and discharge to hospice and 30-day readmission in patients who received definitive treatment with a newer BL/BLI to those who received TABL.
Results: In 353 patients who received definitive antibiotics for S-CRPA, the proportion of cases treated with BL/BLIs increased over time. Forty-seven patients received definitive treatment with a newer BL/BLI and 306 received TABL. Those treated with a newer BL/BLI had longer lengths of stay, and higher Elixhauser comorbidity indices, frequency of bacteremia, and levels of β-lactam resistance than those treated with TABL. Risk factors associated with in-hospital mortality included Elixhauser comorbidity index, length of stay, S-CRPA from a blood or respiratory source, polymicrobial culture, and treatment with newer BL/BLIs. After controlling for age, Elixhauser comorbidity index, length of stay, β-lactam resistance pattern, specimen source, and polymicrobial cultures, treatment with a newer BL/BLI was associated with a statistically non-significant increase in in-hospital mortality (aRR 1.54, 0.93-2.54). In those who survived their initial S-CRPA hospitalization, treatment with newer BL/BLI was not associated with increased 30-day readmission.
Conclusions: In patients with S-CRPA we did not observe a statistically significant difference in clinical outcomes comparing definitive antibiotic treatment with BL/BLI and TABL.
Table of Contents
1) Introduction/Background
6) Methods.
12) Aim 1 Results
13) Aim 2a Results
15) Aim 2b Results
15) Discussion
19) Conclusions
26) Appendix: Tables and figures
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File download under embargo until 22 May 2026 | 2025-03-24 11:55:52 -0400 | File download under embargo until 22 May 2026 |
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