Outcomes of adult patients in the intensive care unit with Pseudomonas aeruginosa pneumonia who received an active anti-pseudomonal β-lactam: Does S equal success in the presence of resistance to other anti-pseudomonal β-lactams?

Study Objectives The most commonly prescribed antibiotics for patients with hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP) due to Pseudomonas aeruginosa are the conventional anti-pseudomonal beta-lactams (APBLs) (ie, ceftazidime, cefepime, meropenem, or piperacillin-tazobactam). Similar resistance mechanisms in P. aeruginosa affect the APBLs, and it is unclear if resistance to one APBL can affect the effectiveness of other APBLs. This exploratory, hypothesis-generating analysis evaluates the impact of APBL resistance among patients in the intensive care unit (ICU) with P. aeruginosa HABP/VABP who initially receive a microbiologically active APBL. Design A retrospective cohort [GJ1] [LT2] study. Setting Kaiser Permanente Southern California members (01/01/2011-12/31/2017). Patients The study included adult patients admitted to the ICU with a monomicrobial P. aeruginosa HABP/VABP who received a microbiologically active APBL within 2 days of index P. aeruginosa respiratory culture. Intervention Patients were stratified by presence of resistance to APBL on index P. aeruginosa (0 vs. >= 1 resistant APBL). Measurements Primary outcomes were 30-day mortality and discharge to home. Main Results Overall, 553 patients were included. Thirty-day mortality was 28%, and 32% of patients were discharged home. Eighty-eight patients (16%) had a P. aeruginosa HABP/VABP that was resistant to >= 1 APBL (other than active empiric treatment). Relative to patients with no APBL resistance, patients with resistance to >= 1 APBL had a higher 30-day mortality (adjusted odds ratio (aOR) [95% confidence interval (CI)]: 1.65 [1.02-2.66]) and were less likely to be discharged home (adjusted hazard ratio (aHR) [95% CI]: 0.50 [0.29-0.85]). Conclusion Further study is needed, but this exploratory analysis suggests that the full APBL susceptibility profile should be considered when selecting therapy for patients with P. aeruginosa HABP/VABP.

Automated summary

This study evaluated the impact of anti-pseudomonal beta-lactam resistance on outcomes in patients with P. aeruginosa HABP/VABP. Patients resistant to at least 1 APBL had a higher 30-day mortality and were less likely to be discharged home compared to those with no APBL resistance.