Abstract
Abstract
Background
Patients with bloodstream infections with antimicrobial resistant bacteria often receive ineffective empirical therapy. The implications are still uncertain.
Methods
We performed a retrospective, multicenter, study of patients with bloodstream infections caused by Extended-Spectrum Beta-Lactamase-producing gram-negative bacteria in southern Sweden from 2013 to 2022. Patients were categorized based on time to effective therapy: ≤24 h (effective empirical therapy) and >24 h (ineffective empirical therapy). Therapy was considered effective if the agent was active in susceptibility testing and administered intravenously at an appropriate dose.
The primary outcome was 30-day mortality. Secondary outcomes were ICU admission and hospital length of stay.
Results
A total of 289/644 (44.9%) patients received ineffective empirical therapy within the first 24 hours after the index blood culture collection. No significant impact of ineffective empirical therapy on 30-day mortality was found in univariable (Hazard ratio 0.66; P=0.15) or multivariable Cox regression analysis (Hazard ratio 0.64; P=0.13). Patients receiving effective empirical therapy were more likely to receive intensive care (Odds ratio 0.38; P=0.008), but the association was non-significant after adjusting for severity of illness and comorbidities.
Ineffective empirical therapy was not associated with a longer hospital stay in Fine–Gray competing risks regression analysis (univariable: sHR 1.15; P=0.082; multivariable: sHR 1.11; P=0.20).
Conclusion
Ineffective empirical therapy was not associated with 30-day mortality, in patients with bloodstream infections with Extended-Spectrum Beta-Lactamase-producing Enterobacterales. If confirmed in prospective studies, our findings could support antimicrobial stewardship efforts by reducing unnecessary empirical carbapenem use without compromising short-term clinical outcomes, particularly in low-prevalence settings