In Vitro Activity of New Cephalosporins vs Streptococcus pneumoniae from the Canadian Bacterial Surveillance Network: 2008–2011

Abstract

Between 2008 and 2011, 6,895 Streptococcus pneumoniae isolates were submitted to the Canadian Bacterial Surveillance Network and underwent in vitro susceptibility testing. Fifteen percent of S. pneumoniae isolates were collected from pediatric patients (0–15 years old), 48.6 % of isolates were collected from adults between 16 and 64 years of age, and 36.1 % from adults aged ≥65 years; age data were not available for 11 patients. Forty-five percent of S. pneumoniae isolates were recovered from sterile specimens, and 55 % of isolates were from nonsterile specimens. Overall, 0.4 % of isolates were resistant to penicillin, 0.4 % to ceftriaxone, 3 % to amoxicillin, 25 % to erythromycin, and 13 % to trimethoprim/sulfamethoxazole; 6.6 % of isolates were multidrug resistant (MDR). Among MDR isolates, resistance rates exceeded 95 % for erythromycin, tetracycline, and trimethoprim/sulfamethoxazole. The MIC90 of cethromycin, ceftaroline, and ceftobiprole against MDR isolates were 0.12, 0.25, and 1 mg/L, respectively. Ceftaroline, the active form of the prodrug ceftaroline fosamil, exhibited potent in vitro activity against the tested S. pneumoniae including all 456 multidrug-resistant strains. No ceftaroline-resistant isolates were identified.