118 - Optimizing the management of coagulase-negative staphylococci (CoNS) contaminants by reporting the species name

Background: CoNS are common isolates in blood cultures (BCx), but many are contaminants contributing to unnecessary antibiotic use. When CoNS are isolated from multiple BCx, different species and/or different susceptibility patterns may suggest contamination. Species reporting of CoNS is not performed at all hospitals. The purpose of this study was to characterize antibiotic use attributable to CoNS positive (pos) BCx and determine if reporting CoNS species could help reduce unnecessary antibiotics.

Methods: A retrospective chart review was conducted of inpatients at an academic medical center before (Jan-June 2017) and after (Sept 2019-Feb 2020) implementation of CoNS species reporting. CoNS species were hidden to providers in the before group. Patients (pts) ≥18 years old with ≥1 BCx pos for CoNS were included. Pts who were neutropenic, treated with anti-staphylococcal antibiotics (SAbx) for a non-CoNS infection, or treated for CoNS with non-SAbx were excluded. Pts were categorized by number of pos BCx (1 vs ≥2). In each period, a random sample of pts was screened until 50 pts with 1 CoNS pos BCx were included. Additional data were collected until at least 50 pts with ≥2 pos BCx were included in each period. The primary outcome was use of SAbx among pts in each group before and after species reporting. Additional analyses were performed to compare the use of SAbx among subsets with same/different species and/or susceptibilities.

Results: 203 pts were included, 102 before and 101 after. 51% and 50% had ≥2 pos BCx in the before and after groups, respectively. S. epidermidis was isolated more frequently in pts with ≥2 pos BCx (75% vs 50%, p< 0.001). 77% of pts received at least 1 SAbx (97% vancomycin). Median SAbx days of therapy per pt (DOTs) was greater among pts with ≥2 pos BCx (1 vs 5, p< 0.001). There was no difference in overall DOTs between the two periods (3 vs 2, p=0.25). However, among pts with ≥2 pos BCx, median DOTs was less in the after period (6.5 vs 3, p=0.016). Among pts with 1 pos BCx, median DOTs was 1 in both periods.Median Anti-Staphylococcal Antibiotic Days of Therapy per Patient (≥ 2 positive cultures)


Conclusion: CoNS species reporting was associated with decreased SAbx use for pts with ≥2 pos BCx, suggesting that knowing the species helps in determining likelihood of true infection. Institutions may realize improved stewardship metrics of SAbx by implementing CoNS species reporting for pos BCx.