Daptomycin In Vitro Activity against Methicillin-Resistant Staphylococcus aureus Is Enhanced by d-Cycloserine in a Mechanism Associated with a Decrease in Cell Surface Charge

O Gasch; S K Pillai; J Dakos; S Miyakis; R C Moellering Jr; G M Eliopoulos

doi:10.1128/AAC.00799-13

Daptomycin In Vitro Activity against Methicillin-Resistant Staphylococcus aureus Is Enhanced by d-Cycloserine in a Mechanism Associated with a Decrease in Cell Surface Charge

Antimicrob Agents Chemother. 2013 Sep;57(9):4537-4539. doi: 10.1128/AAC.00799-13. Epub 2013 Jun 24.

Authors

O Gasch^{1

2

3}, S K Pillai^{4

2}, J Dakos⁴, S Miyakis^{4

2

5}, R C Moellering Jr^{4

2}, G M Eliopoulos^{4

2}

Affiliations

¹ Beth Israel Deaconess Medical Center [email protected].
² Harvard Medical School, Boston, Massachusetts, USA.
³ Hospital Universitari de Bellvitge, Barcelona, Spain.
⁴ Beth Israel Deaconess Medical Center.
⁵ Graduate School of Medicine, University of Wollongong, New South Wales, Australia.

Abstract

The killing activity of daptomycin against an isogenic pair of daptomycin-susceptible and daptomycin-nonsusceptible (DNS) methicillin-resistant Staphylococcus aureus (MRSA) strains was enhanced by the addition of certain cell wall agents at 1× MIC. However, when high inocula of the DNS strain were used, no significant killing was observed in our experiments. Cytochrome c binding assays revealed d-cycloserine as the only agent associated with a reduction in the cell surface charge for both strains at the concentrations used.