title: Daptomycin-Nonsusceptible Staphylococcus aureus: The Role of Combination Therapy with Daptomycin and Gentamicin.
abstract: Reduced susceptibility to daptomycin in Staphylococcus aureus has now been described, leading to clinical failures. Here we determined the impact of daptomycin and gentamicin combination therapy on bactericidal activity and resistance emergence using daptomycin-susceptible and -resistant isolates with mutations linked to previous daptomycin or vancomycin exposure. Enhanced killing of S. aureus was observed when gentamicin was combined with daptomycin, most commonly with daptomycin concentrations below the peak serum free-drug concentrations achieved with standard dosing. Synergy was seen with daptomycin-susceptible isolates and with isolates resistant to vancomycin and daptomycin. Combination therapy also prevented the emergence of resistance. Daptomycin and gentamicin combination therapy may provide the synergy required to prevent emergence of resistance when daptomycin levels are below peak serum concentrations as would be found in deep-seated, complicated infections.
authors.affiliation: Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia. jhih-hang.jiang@monash.edu.
authors.forename: Jhih-Hang
authors.initials: JH
authors.lastname: Jiang
authors.affiliation: Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia. anton.peleg@monash.edu.|Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia. anton.peleg@monash.edu.
authors.forename: Anton Y
authors.initials: AY
authors.lastname: Peleg
keywords: MRSA; S. aureus; VISA; combination therapy; synergy; time-kill studies