In vivo therapeutic efficacy of cefdinir (FK482), a new oral cephalosporin, against Staphylococcus aureus and Haemophilus influenzae in mouse infection models

Abstract

Cefdinir (FK482), a new oral cephalosporin, displayed potent oral activity versus induced infections in mice. In studies using beta-lactamase-nonproducing (beta LAC-) and -producing (beta LAC+) Staphylococcus aureus strains, respective PD50s (in mg/kg) were 11 and 24 for preventing subcutaneous abscess and 2.7 and 2.3 for preventing lethal systemic infection. In studies using beta LAC- and beta LAC+ Haemophilus influenzae, respective PD50s were 5.8 and 3.1 for preventing lethal systemic infection. Time-kill studies versus H. influenzae showed that 6- to 12-mg/kg dosing was effective in reducing viable counts of these strains in blood by > or = 100-fold by 24 h after challenge. This in vivo performance was comparable to or exceeded values generated by cefaclor, cefpodoxime proxetil, and ampicillin.