Antimicrobial Activity and Spectrum of the Novel Cephalosporin Ceftaroline Tested Against Bacterial Isolates Causing Skin and Skin Structure Infections in USA Medical Centers

• S. aureus was the most frequently recovered cSSSI pathogen (59.7%) from the consecutively collected isolates within monitored USA medical centers, and 53.5% of the S. aureus were MRSA. The next most common pathogens were E. coli (9.3%), P. aeruginosa (5.7%), E. faecalis (4.8%), Enterobacter spp. (4.6%), Klebsiella spp. (4.5%), and βhaemolytic streptococci (3.5%; Table 1) • Methicillin-susceptible S. aureus (MSSA) isolates had slightly lower ceftaroline MIC values (MIC 50/90 , 0.25/0.5 μg/mL) compared with MRSA isolates (MIC 50/90 , 1/1 µg/mL; Tables 1 and 2). Against MSSA and MRSA, the highest MIC results observed were 0.5 and 2 μg/mL, respectively • The most active agents tested against MRSA isolates were: ceftaroline (MIC 90 , 1 μg/mL; 100% inhibited at ≤2 μg/mL), linezolid (MIC 90 , 2 μg/mL; 100% susceptible [S]), vancomycin (MIC 90 , 1 μg/mL; 100% S), daptomycin (MIC 90 , 0.5 μg/mL; 100% S), and tigecycline (MIC 90 , 0.25 μg/mL; 100% S). In contrast, the highest resistance rate was observed for erythromycin (91.5%), followed by levofloxacin (55.0%) and clindamycin (19.7%; Table 2)