Effect of Direct-from-blood Bacterial Testing on Antibiotics Administration in Adults Presenting with Acute Infection: A Randomized Trial

Abstract

Background For hospitalized adults receiving empiric antibiotic therapy, antibiotic de-escalation prevents unnecessary exposure and adverse effects. Whether use of direct-from-blood bacterial testing facilitates earlier antibiotic de-escalation and improves clinical outcomes has never been evaluated in a randomized trial. Methods Between December 2023 and December 2024, this pragmatic randomized trial compared direct-from-blood bacterial testing with blood cultures (intervention group) to blood cultures alone (usual care group) in adults with suspected infection receiving empiric intravenous vancomycin in the emergency department of an academic medical center. The primary and secondary outcomes were time from randomization to last dose of intravenous vancomycin and systemic antipseudomonal beta-lactam antibiotics, respectively. Results Among 500 patients enrolled, the time from randomization to results of bacterial testing from blood (direct-from-blood test, gram stain, or negative culture) was a median of 5.2 days shorter (95% CI, 5.1-5.2) in the direct-from-blood test group (median 0.4 days; IQR, 0.3-0.5) than the usual care group (median, 5.5 days; IQR, 5.2-5.6). The time between randomization and the last dose of intravenous vancomycin did not differ between the direct-from-blood test group (median, 12.5 hours; IQR, 0.79-57.8) and the usual care group (median, 19.0 hours; IQR 0.9-64.8) (HR, 1.08; 95% CI,. 90-1.28; P =. 42), nor did the time to last dose of systemic antipseudomonal beta-lactam antibiotics (HR, 1.04; 95% CI. 87-1.24). Clinical outcomes were also similar. Conclusions Among adults with suspected infection receiving empiric intravenous vancomycin in the emergency department, use of direct-from-blood bacterial testing did not shorten the duration of intravenous vancomycin or antipseudomonal beta-lactam antibiotics.