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 β-lactamase-nonproducing (β LAC −) and -producing (β LAC +) Staphylococcus aureus strains, respective PD 50 s (in mg/kg) were 11 and 2.3 for preventing subcutaneous abscess and 2.7 and 2.3 for preventing lethal systemic infection. In studies using β LAC − and β LAC + Haemophilus influenzae , respective PD 50 s 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 dtrains in blood by ⩾ 100- fold by 24 h after challenge. This in vivo performance was comparable to or exceeded values generated by cefaclor, cefpodoxime proxetil, and ampicillin.