Background: Prompt identification of blood culture contaminants can limit the use of antimicrobics, improve patient outcomes, and reduce costs. Most patients with Gram-positive cocci (GPC) blood cultures are empirically started on vancomycin. Coagulase-negative staphylococci (CoNS) are commonly isolated but only 20% of such cultures represent true infection. Banner hospitals implemented Nanosphere Verigene System, a molecular diagnostic technology in 2013. The purpose of this investigation was to determine if this technology decreased vancomycin duration, the number of vancomycin assays performed, and hospital length of stay.
Methods: We performed retrospective chart reviews of patients aged 18 years or greater admitted from the emergency department at four Banner hospitals with 1 of 2 blood cultures positive for CoNS in January and February 2013 and 2014. Subjects were excluded if they expired during hospitalization, were determined to have true CoNS bacteremia, or had mixed culture results. We recorded time from GPC detection to CoNS identification by molecular detection and traditional culture techniques. We recorded vancomycin duration, the number of vancomycin assays, and hospital length of stay. Basic descriptive statistical analysis on primary outcomes was performed using SPSS. Continuous variables were compared using t-tests or Mann-Whitney tests for normal and non-normal data respectively.
Results: There were 114 subjects in the pre-intervention and 72 in the post-intervention groups. The mean time to detection of CoNS using traditional culture technique versus molecular detection was 29.6 hours and 4.4 hours (p < 0.001), respectively. The mean duration of vancomycin use was 49.5 versus 27.3 hours (p < 0.024) and mean hospital length of stay was 5.9 versus 4.5 days (p < 0.009) in the pre-versus post-intervention groups, respectively. The mean number of vancomycin assays was 0.39 in both groups.
Conclusion: Molecular diagnostic technology decreased time to detection of blood culture contaminants, contributing to decreased vancomycin duration and hospital length of stay. Not only does this technology promote antimicrobial stewardship, it also implies cost savings, particularly by reducing hospital length of stay by nearly 1.5 days.
C. O'malley, None