Clinical outcomes associated with blood-culture contamination are not affected by utilization of a rapid blood-culture identification system

Objective: Contaminated blood cultures result in extended hospital stays and extended durations of antibiotic therapy. Rapid molecular-based blood culture testing can speed positive culture detection and improve clinical outcomes, particularly when combined with an antimicrobial stewardship program. We investigated the impact of a multiplex polymerase chain reaction (PCR) FilmArray Blood Culture Identification (BCID) system on clinical outcomes associated with contaminated blood cultures. Methods: We conducted a retrospective cohort study involving secondary data analysis at a single institution. In this before-and-after study, patients with contaminated blood cultures in the period before PCR BCID was implemented (ie, the pre-PCR period; n = 305) were compared to patients with contaminated blood cultures during the period after PCR BCID was implemented (ie, the post-PCR implementation period; n = 464). The primary exposure was PCR status and the main outcomes of the study were length of hospital stay and days of antibiotic therapy. Results: We did not detect a significant difference in adjusted mean length of hospital stay before (10.8 days; 95% confidence interval [CI], 9.8-11.9) and after (11.2 days; 95% CI, 10.2-12.3) the implementation of the rapid BCID panel in patients with contaminated blood cultures (P =.413). Likewise, adjusted mean days of antibiotic therapy between patients in pre-PCR group (5.1 days; 95% CI, 4.5-5.7) did not significantly differ from patients in post-PCR group (5.3 days; 95% CI, 4.8-5.9; P =.543). Conclusion: The introduction of a rapid PCR-based blood culture identification system did not improve clinical outcomes, such as length of hospital stay and duration of antibiotic therapy, in patients with contaminated blood cultures.