RESUMO
Rapid diagnostic tests (RDTs) for bloodstream infections (BSIs) decrease the time to organism identification and resistance detection. RDTs are associated with early deescalation of therapy for Gram-positive BSIs. However, it is less clear how RDTs influence antibiotic management for Gram-negative BSIs and whether RDT results are acted on during off-hours. We performed a single-center, retrospective review of children with BSI and Verigene (VG) testing at a children's hospital. Of the 301 positive cultures included in the study (196 Gram-positive, 44 Gram-negative, 32 polymicrobial, and 29 non-VG targets), the VG result had potential to impact antibiotic selection in 171 cases; among these, antibiotic changes occurred in 119 (70%) cases. For Gram-negative cultures, the Verigene result correlated with unnecessary antibiotic escalation and exposure to broader-spectrum antibiotics than needed. In contrast, for Gram-positive cultures, the VG results correlated with appropriate antibiotic selection. VG results permitted early deescalation for methicillin-susceptible Staphylococcus aureus (MSSA) (19/24 [79%]) and avoidance of antibiotics for skin contaminants (30/85 [35%]). Antibiotic changes occurred more quickly during the day than at night (4.6 versus 11.7 h, respectively; P < 0.05), and antibiotic escalations occurred more quickly than did deescalations (4.1 versus 10.1 h, P < 0.01). In a pediatric institution with a low prevalence of Gram-negative resistance, the VG RDT facilitated antibiotic optimization for Gram-positive BSIs but led to unnecessary escalation of antibiotics for Gram-negative BSIs. The time to action was slower for RDT results reported at night than during the day. Laboratories should consider these factors when implementing blood culture RDTs.
