CP6679, a new injectable cephalosporin with broad spectrum and potent activities against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa.

The antibacterial activities of CP6679, a new injectable cephalosporin with a broad antibacterial spectrum, were compared with those of other cephalosporins. CP6679 had stronger in-vitro activity than ceftazidime and cefpirome against methicillin-resistant Staphylococcus aureus(MRSA), methicillin-resistant coagulase-negative staphylococci, and Pseudomonas aeruginosa. Its activity against MRSA was eight times stronger than that of cefpirome, and it showed high binding affinity for penicillin-binding protein 2' of MRSA. Furthermore, the antibacterial activity of CP6679 against ceftazidime-resistant and imipenem-resistant P. aeruginosawas eight times stronger than that of ceftazidime and four times stronger than that of imipenem. In addition to its in-vitro activities, CP6679 showed the highest efficacy among all cephalosporins tested in murine models of systemic infection induced by MRSA or P. aeruginosa. It was more effective than vancomycin and cefpirome against respiratory tract infections induced by MRSA in mice.