Activity of Ceftaroline against Aerobic Gram-Positive and Gram-Negative Pathogens: Effect of Test Method Variability

Ceftaroline is a new cephalosporin with bactericidal activity against methicillin-resistant S. aureus (MRSA) as well as gram-negative pathogens. Variations of in vitro test conditions were found to affect ceftaroline activity, with 5% NaCl inhibiting growth and/or reducing the minimum inhibitory concentrations (MICs) for E. coli, K. pneumoniae, M. catarrhalis, H. influenzae, and streptococci, while an inoculum of 10(6) CFU/mL raised MICs of some E. coli, K. pneumoniae, and M. catarrhalis strains.