Protocolized antimicrobial stewardship following filmarray pneumonia plus panel testing in mechanically ventilated patients with severe lower respiratory tract infection

We evaluated the impact of the implementation of a protocolized list of antimicrobial stewardship actionables based upon the results of the Biofire Filmarray pneumonia plus panel (FA-PP) on antimicrobial use in mechanically-ventilated critically ill patients with lower respiratory tract infection and its cost-effectiveness compared to the standard-of-care. Retrospective, pre- and post-FA-PP-implementation study including 213 consecutive patients, of which most (n = 198) were under empirical antimicrobial therapy (EAT) at the time of testing. Endotracheal aspirates were usually processed for microbiological testing. The primary study outcome was the number of participants with administration of antimicrobials or subjected to changes in EAT deemed to be appropriate. Secondary outcomes were the time to antimicrobial stewardship; and the total number of days on antimicrobial therapy. Conventional culture retrieved clinically significant results in 48/113 (42.4%) and 37/100 (37%) in the pre-FA-PP and post- FA-PP periods (P = 0.48). FA-PP increased the detection yield compared to conventional culture. The spectrum of bacterial species involved was comparable across both periods. Appropriate and proportionate adjustment of EAT was made more frequently in the post-FA-PP phase (54/89; 60.6%) than in the pre-FA-PP phase (55/109; 50.4%) (P = 0.15) and at earlier times. When considering the entire pre-FA-PP and post-FA-PP cohorts, no difference was noticed on duration of antimicrobial treatments (mean, 7.1 days vs. 7.6 days, respectively (P = 0.32). Nevertheless, adequate selection of patients for FA-PP testing enabled a reduction in the total number of antibiotic treatment days, with an Incremental Cost-Effectiveness Ratio of €151/day. Antimicrobial stewardship driven by the FA-PP panel results was sped up relative to that based upon standard practice with at least a comparable appropriateness and a rather negligible increase in costs.