Clinical Impact of Rapid Molecular Diagnosis of Bloodstream Infections: A Randomized Controlled Trial

Rapid identification of pathogens and antimicrobial resistance is important for optimizing therapies for bloodstream infections. We conducted a randomized controlled trial comparing standard of care (SOC) culture and phenotypic antimicrobial susceptibility testing with SOC plus BioFire BCID2 testing (Multiplex PCR arm).

Patients with positive blood cultures were randomized 1:1 to the SOC or multiplex PCR arm, both with antimicrobial stewardship. The primary outcome was the time from randomization to the first effective antimicrobial modification within 120 h. The secondary outcomes were persistent bloodstream infections, mortality, and length of hospital stay.

Among 418 patients (208 SOC, 210 multiplex PCR), the median time to first effective antimicrobial modification was significantly shorter in the multiplex PCR arm (23.2 vs. 64.5 h; P < 0.001). This was consistent across gram-negative (30.5 vs. 77.1 h; P < 0.001), gram-positive (22.7 vs. 53.5 h; P = 0.001), and yeast infections (2.9 vs. 27.7 h; P < 0.001). The reduction was maintained regardless of laboratory hours (regular hours: 9.3 vs. 66.7 h; off-hours: 37.5 vs. 60.5 h; P < 0.001) and intensive care unit (ICU) status (ICU: 20.5 vs. 84.8 h; P < 0.001; non-ICU: 23.4 vs. 55.5 h; P < 0.001). The multiplex PCR arm showed a lower rate of persistent bloodstream infections (5.7% vs. 11.5%, P = 0.038). No significant differences were observed in 30-day mortality or length of stay.

Rapid multiplex PCR shortened the time to effective antimicrobial modification in patients with bloodstream infections.