Prospective intervention study with a microarray-based, multiplexed, automated molecular diagnosis instrument (Verigene system) for the rapid diagnosis of bloodstream infections, and its impact on the clinical outcomes.

The Verigene Gram-positive blood culture test (BC-GP) and the Verigene Gram-negative blood culture test (BC-GN) identify representative Gram-positive bacteria, Gram-negative bacteria and their antimicrobial resistance by detecting resistance genes within 3 h. Significant benefits are anticipated due to their rapidity and accuracy, however, their clinical utility is unproven in clinical studies. We performed a clinical trial between July 2014 and December 2014 for hospitalized bacteremia patients. During the intervention period (N = 88), Verigene BC-GP and BC-GN was used along with conventional microbiological diagnostic methods, while comparing the clinical data and outcomes with those during the control period (N = 147) (UMIN registration ID: UMIN000014399). The median duration between the initiation of blood culture incubation and the reporting time of the Verigene system results was 21.7 h (IQR 18.2-26.8) and the results were found in 88% of the cases by the next day after blood cultures were obtained without discordance. The hospital-onset infection rate was higher in the control period (24% vs. 44%, p = 0.002), however, no differences were seen in co-morbidities and severity between the control and intervention periods. During the intervention period, the time of appropriate antimicrobial agents' initiation was significantly earlier than that in the control period (p = 0.001) and most cases (90%; 79/88) were treated with antimicrobial agents with in-vitro susceptibility for causative bacteria the day after the blood culture was obtained. The costs for antimicrobial agents were lower in the intervention period (3618 yen vs. 8505 yen, p = 0.001). The 30-day mortality was lower in the intervention period (3% vs. 13%, p = 0.019).