Inactivation of Cephalosporins by Bacteroides

摘要: Abstract We investigated the relationship between β-lactamases of Bacteroides fragilis organisms and their resistance to cephalosporins. Timed killing curves were used study in vitro activity three cephalosporins, cephalothin, cefazolin, cefamandole, a semisynthetic cephamycin, cefoxitin. Measurements residual antibiotic concentrations culture supernatants made, they compared with β-lactamase microorganism. A cephalosporin-susceptible strain was rapidly killed by Four cephalosporin-resistant strains not or cefamandole but An inoculum effect noted cefazolin The resistant inactivated there no inactivation constitutive detected all isolates B. group that There distinction species based on isoelectric focusing enzyme. These data suggest may be mechanism for cephalosporins would explain enhanced