Abstract
The penetration of FK749 to the outer membrane was compared with those of the five other new cephalosporins: cefotiam, cefuroxime, cefotaxime, cefmetazole and cefoxitin, using a clinical isolate of Enterobacler cloacae as a test strain. The estimation of the permeability was performed by the method utilizing the inhibiting activities of the cephalosporins against the β-lactamase which is localized in the periplasm. Of the cephalosporins tested, FK749 as well as cefmetazole gave the remarkably high concentrations in the periplasm, several times higher than those of cefotaxime and cefoxitin and ten to several tens times higher than those of cefuroxime and cefotiam. The approximate permeability coefficient of FK749 was several times superior to those of cefotiam and cefmetazole and several tens times superior to those of cefoxitin, cefuroxime and cefotaxime.
