Enterobacteriaceae
Enterococci
Bacteroides
Ampicillin 200 mg/kg/day IV in 4-6 divided doses (max: 12 gm/day)
PLUS
Metronidazole 15 mg/kg loading dose, followed by 7.5 mg/kg/dose IV q8h
Cefotaxime 200 mg/kg/day IV in 4 divided doses