Clinical impact of rapid antimicrobial susceptibility testing in patients with bacteremia due to gram-negative...

Bacteremia and sepsis cause high morbidity and mortality worldwide. Rapid identification of bacteria and timely antimicrobial susceptibility testing (AST) can be crucial for patient survival. In the present study, we have compared isolates from patients whose ASTs were processed using MicroScan Walkaway Plus with those patients whose ASTs were processed more quickly using Vitek® Reveal™. We analyzed mortality, turnaround time to targeted therapy, and length of stay between the two groups, as well as other parameters.

In this prospective study, 120 patients with bacteremia caused by Gram-negative bacilli were included. In 60 patients, conventional AST (MicroScan WalkAway Plus) was performed, whereas in the other 60 patients, rapid AST (Vitek® Reveal™) was carried out.

The mortality rates were 13.3% and 38.3% for patients whose ASTs were performed with Vitek® Reveal™ and MicroScan WalkAway Plus, respectively (p=0.002). The average length of stay was 18 days per patient in the Vitek® Reveal™ group and 24.5 days for the MicroScan group (p=0.128). The average turnaround time was 12 hours per patient for Vitek® Reveal™ and 40 hours for MicroScan (p<0.001).

The introduction of rapid AST techniques such as Vitek® Reveal™ has allowed a shorter turnaround time for reports on AST than when using normal AST techniques. This allows most AST results to be available earlier in the Laboratory Information System, allowing physicians to initiate more quickly in establishing correct treatment. Finally, these actions have resulted in reduced mortality due to faster clinical decision-making in these critically ill patients.