A Retrospective Study on the Use of Daptomycin and Linezolid in Singapore General Hospital

Background: Vancomycin-resistant Enterococcus (VRE) has emerged as a major nosocomial pathogen. A recent surveillance of our hospital identified a concerning rise in VRE bacteremia since 2020, despite the stable use of broad-spectrum antibiotics. This trend, coupled with the increased use of daptomycin and linezolid for drug-resistant Gram-positive bacteremia (GPB), prompted an evaluation of their usage beyond approved hospital indications. Methods: A retrospective analysis was carried out from 1 February 2023 to 31 July 2023, during which 100 and 195 patients received linezolid and daptomycin, respectively. Patients' data were extracted from the hospital's electronic medical records, and the appropriateness of the antibiotics prescribed was assessed. The amount of daptomycin and linezolid utilization during the study period was also retrieved, as was the incidence of VRE bacteremia. Results: A total of 295 courses of VRE-active agents, linezolid (n = 100) and daptomycin (n = 195), were assessed for appropriateness in this study. Linezolid and daptomycin use were judged as inappropriate 5.0% and 9.2% of the time, respectively. The primary reason for inappropriate linezolid use was overly broad empirical therapy where first-line options like cefazolin and vancomycin could have been prescribed. Daptomycin was often used inappropriately in non-VRE infections, and surgical prophylaxis or use was extended unnecessarily without microbiological justification. Conclusions: Linezolid and daptomycin were prescribed appropriately. Nevertheless, our findings suggest the need to re-evaluate the empirical treatment strategies especially in VRE-colonized patients. Implementation of robust risk-based criteria as well as in-house hospital guidelines or protocols on the initiation of VRE-active agents may help support more judicious prescribing practices of these agents.