substituent atthe7position, was evaluated incomparison withcefaclor andcephalexin and,whenappropriate, ampicillin andvancomycin. Invitro, BMY 28100 was more active thanthereference cephalosporins against streptococci, Staphylococcus aureus,Staphylococcus epidermidis, Listeria nionocyto- genes,Haemophilus influenzae, Propionibacterium acnes,Clostridiunm perfrigens, andClostridium difficile. BMY 28100 was comfparable tocefaclor andmore active thaneephalexin against Staphylococcus saprophyticus and