[In vitro activity of oral cephalosporins (author's transl)].

The in vitro activity of cephradine, cephalexin, and cefaclor was studied in comparison with that of cephalothin. Cefaclor inhibits peptidoglycan synthesis somewhat more than cephalexin and cephradine. There is no marked difference in the stability of the three substances in the presence of beta-lactamases, and the outer membrane of Escherichia coli is no barrier to permeation of any of the three antibiotics.