Antimicrobial Susceptibility StudiesAntimicrobial activity of ceftaroline and comparator agents tested against bacterial isolates causing skin and soft tissue infections and community-acquired respiratory tract infections isolated from the Asia-Pacific re

Ceftaroline, the active metabolite of the prodrug ceftaroline fosamil, is a cephalosporin with in vitro bactericidal activity against resistant Gram-positive organisms including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant strains of Streptococcus pneumoniae, and common Gram-negative organisms, including wild-type Enterobacteriaceae. We evaluated the in vitro activity of ceftaroline and selected comparator agents against bacterial isolates collected from patients with skin and soft tissue infections (SSTI) and community-acquired respiratory tract infections (CARTI) in the Asia-Pacific region and South Africa. A total of 2351 isolates, 1100 from SSTI and 1251 from CARTI, were collected from 25 medical centers distributed across 8 countries as part of the 2010 AWARE ceftaroline surveillance program and tested for susceptibility by reference broth microdilution methods. Ceftaroline was very active against S. aureus (MIC50/90, 0.25/1 μg/mL; 93.4% susceptible), including MRSA (MIC50/90, 1/2 μg/mL; 80.6% susceptible). Against β-hemolytic streptococci, ceftaroline demonstrated greater activity (MIC90, 0.015 μg/mL) than penicillin (MIC90, 0.06 μg/mL). Ceftaroline was also highly active against viridans group streptococci (MIC90, 0.12 μg/mL). Similarly to ceftriaxone, ceftaroline activity against Escherichia coli (MIC50/90, >32/>32 μg/mL) and Klebsiella spp. (MIC50/90, 0.12/>32 μg/mL) was compromised by the high prevalence of isolates with an ESBL phenotype in the region, particularly in China. Ceftaroline was the most potent β-lactam tested against S. pneumoniae (MIC50/90 of 0.015/0.25 μg/mL; 99.8% susceptible by Clinical and Laboratory Standards Institute [CLSI] criteria), and it was also highly potent against Haemophilus influenzae (MIC50/90, ≤0.008/0.03 μg/mL; 100% susceptible by CLSI criteria). Ceftaroline was also active against H. parainfluenzae (MIC50/90, ≤0.008/0.015 μg/mL) and Moraxella catarrhalis (MIC50/90, 0.06/0.12 μg/mL). In summary, ceftaroline showed potent in vitro activity against a large collection of bacterial isolates (2351) associated with SSTI and CARTI from the Asia-Pacific region and South Africa.