Rates of killing of methicillin-resistant Staphylococcus aureus by ceftaroline, daptomycin, and telavancin compared to that of vancomycin

Treatment failure of methicillin-resistant Staphylococcus aureus (MRSA) remains an important concern. In order to investigate new MRSA treatment modalities, we used standard time-kill assays to determine the in vitro killing rate of 22 strains of MRSA by vancomycin, telavancin, daptomycin, and ceftaroline. Studies were carried out with 7-10-times the minimum bactericidal concentrations of each antibiotic in broth culture for 24 h, with subculture at 4, 8, and 24 h. We found that killing by ceftaroline closely paralleled that of vancomycin. Telavancin killed bacteria significantly more slowly, whereas daptomycin killed significantly more rapidly.