Combination of ertapenem and penicillin M or cefazolin in the treatment of methicillin-susceptible Staphylococcus aureus bacteremia: multicenter case series.

BACKGROUND Dual therapy (DT) combining penicillin M or cefazolin with ertapenem has been proposed as treatment of complicated Staphylococcus aureus bacteremia (SAB). We aimed to outline the relevant clinical characteristics and outcomes in real-life practice.

METHODS We conducted a multicenter retrospective study involving SAB cases treated by means of DT in five French university hospitals between January 2022 and December 2024.

RESULTS Thirty-five patients were included, all of them suffering from complicated SAB. Although DT was prescribed for persistent bacteremia, due to protracted blood culture incubation, at the time when DT was finally initiated, only 21 patients (60%) had positive blood cultures,. Median bacteremia duration after DT was two days (IQR 1-3). Two serious adverse events (5.7%), both having to do with to encephalopathy, were reported. Seven patients (20%) died, five on account of SAB.

CONCLUSIONS Due to the time taken to obtain usable blood culture, 40% of the patients had already cleared bacteremia before DT could be initiated. Further studies are needed to better define the role of this strategy and to identify the patients most likely to benefit.