Structured integration of rapid antimicrobial susceptibility testing and antimicrobial resistance detection into an antimicrobial stewardship programme for bacteraemia

Background: Bloodstream infections are associated with substantial morbidity and mortality. Rapid diagnostic tests (RDTs) have been shown to improve clinical outcomes when combined with antimicrobial stewardship (AMS) programmes. The lack of systematic reporting of rapid antimicrobial susceptibility testing (AST) can cause delays in communication to prescribers and in targeted antimicrobial treatment. Objectives: To evaluate the impact of a structured intervention in integrating systematic RAST and AMR detection within an existing AMS programme. The main outcomes were time to report (from Gram to AST report) (TTR), time from Gram to AMS recommendation (TAMS) and time to change antimicrobial prescription (TCAP) following this recommendation. Methods: We performed a contemporaneous comparative study evaluating episodes of bacteraemia managed with rapid AST (RAST) and/or antimicrobial resistance mechanisms (AMR) detection integrated into AMS workflows versus episodes managed without RAST/AMR during the same implementation period. Results: Episodes managed with RAST/AMR had significantly shorter TTR, TAMS and TCAP compared with episodes without RAST/AMR (median absolute reduction in hours of 31, 37 and 24, respectively). There was no significant reduction in duration of antimicrobial therapy, hospital length of stay (LOS) or mortality in the RAST/AMR group. Compliance with AMS recommendations was high (90%). Conclusions: As reported previously, RAST or AMR detection in combination with AMS was an effective strategy for targeting antimicrobial therapy. This intervention demonstrates that structured implementation of RAST/AMR detection, when embedded within the AMS workflow, can substantially shorten time to targeted therapy even in settings with pre-existing AMS infrastructure.