Efficacy of daptomycin in the treatment of enterococcal endocarditis: a 5 year comparison with conventional therapy

Abstract

Objectives: Enterococcus spp. account for 10% of infective endocarditis (IE). Although daptomycin is a bactericidal drug with in vitro activity against Enterococcus, there is little experience of its use in IE. We analysed the effectiveness of daptomycin in the treatment of enterococcal IE (EIE).

Methods: This was a retrospective descriptive study comparing the efficacy of daptomycin versus ampicillin/ceftriaxone versus conventional antibiotic regimens (ampicillin or vancomycin ± gentamicin) in EIE.

Results: From January 2007 to December 2011, 6 patients with EIE treated with daptomycin monotherapy were compared with 21 patients treated with ampicillin/ceftriaxone and 5 patients treated with ampicillin or vancomycin ± gentamicin. The three groups had similar epidemiological and clinical characteristics. Daptomycin indications were allergy to β-lactams (n = 3), therapy simplification (n = 2), renal failure (n = 2) and Enterococcus faecium resistant to ampicillin/gentamicin (n = 1). Daptomycin MICs ranged from 1 to 2 mg/L and the doses were 6-10 mg/kg/day intravenously. Daptomycin patients had longer duration of bacteraemia (6 versus 1 day, P < 0.01) and greater need of therapy switch due to complications (66.7% versus 0%, P < 0.01). There were no differences regarding duration of hospital stay or mortality.

Conclusions: Daptomycin-treated patients more frequently required a therapeutic change due to worse microbiological and clinical response, although mortality was not increased. Our findings do not support the use of daptomycin as single therapy in the treatment of EIE. Its role in combined strategies should be further investigated.

Keywords: Enterococcus; antimicrobial therapy; infective endocarditis; outpatient parenteral therapy.