High-dose daptomycin for the treatment of invasive infections due to Enterococcus faecalis isolates with intermediate...

Enterococcus faecalis isolates with a daptomycin minimum inhibitory concentration (MIC) of 4 mg/L are classified as intermediate by the Clinical and Laboratory Standards Institute (CLSI). There is limited evidence to guide the use of high-dose daptomycin for these infections when alternative therapy options cannot be used.

To determine the rate of clinical failure of E. faecalis invasive infections with a daptomycin MIC of 4 mg/L treated with high-dose daptomycin or best alternative therapy (BAT).

This was a single-centre, retrospective, observational, cross-sectional study that compared high-dose daptomycin to BAT for invasive E. faecalis infections. High-dose daptomycin was defined as ≥8 mg/kg/dose. The primary outcome was clinical failure, a composite endpoint including switch from definitive to alternative therapy secondary to clinical decline, infection-related hospital readmission while on definitive treatment for the index infection, or infection-related mortality within 30 days of definitive therapy completion. High-dose daptomycin versus BAT groups were matched and compared in a 1:3 ratio based on initial source of the positive E. faecalis isolate.

Of 112 patients included, 28 patients received daptomycin and 84 received BAT. There was no difference in the primary outcome of clinical failure between the daptomycin and BAT groups (7% versus 5%, P = 0.64). All-cause mortality was similar between the daptomycin and BAT groups (11% versus 10%, P = 1.00).

There was no difference observed in clinical failure rates between patients treated with high-dose daptomycin versus BAT. All-cause mortality was also similar between the groups. Further studies are needed to confirm these findings in high-burden E. faecalis infections with intermediate daptomycin susceptibility.