The activity of the siderophore cephalosporin cefiderocol is targeted against carbapenem-resistant Gram-negative bacteria. In this study, the activity of cefiderocol against characterized carbapenem-resistant Acinetobacter baumannii complex, Stenotrophomonas maltophilia , Pseudomonas aeruginosa , and Enterobacteriaceae strains was determined by microdilution in iron-depleted Mueller-Hinton broth.
The in vitro activity of ceftaroline against 891 pneumococci collected in 2008 from 22 centers in the United States was investigated. Ceftaroline was the most potent agent tested, with the MICs being <0.008 to 0.5 μg/ml and the MIC 90 s being <0.008 to 0.25 μg/ml against 11 prevailing serotypes. The overall rates of susceptibility were as follows: penicillin G, 86.2%; ceftriaxone, 90.7%; cefuroxime, 70.1%; erythromycin, 61.6%; clindamycin, 79.2%; levofloxacin, 99.4%; and vancomycin, 100%. Serotype 19A isolates were the least susceptible. These results support the use of ceftaroline for the treatment of pneumococcal infections, including those caused by pneumococci resistant to other agents.