In vitro activity and beta-lactamase stability of the oral cephalosporin BMY-28100.

BMY-28100 was compared with cephalexin, cefaclor, cefixime, and cefteram and found to be more active than the reference cephalosporins against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, and Clostridium difficile. BMY-28100 was the next most active, after cefteram, against Streptococcus pyogenes and Streptococcus pneumoniae. Against gram-negative bacteria, BMY-28100 showed similar activity to that of cefaclor. The antimicrobial activity of BMY-28100, including bactericidal activity, against Staphylococcus aureus was less affected by penicillinase-production than was that of cefaclor. BMY-28100 was more stable than cefaclor against various types of penicillinases, especially against the penicillinase from Staphylococcus aureus.