Third-generation cephalosporins resistance in clinical isolates of Enterobacteriaceae.
Seven clinical isolates of Enterobacteriaceae resistant to third-generation cephalosporins were investigated in order to assess the role played in resistance by permeability barrier and by beta-lactamase production. The addition of subinhibitory concentrations of EDTA increased susceptibility to ceftriaxone in five strains showing that the permeability barrier is involved. All strains produced different amounts of beta-lactamases that were always increased by cefoxitin induction. Hydrolytic activity of investigated enzymes varied in different cephalosporins; ceftriaxone and ceftazidime are the most stable compounds.
D002511:Cephalosporins / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D013045:Species Specificity; D013329:Structure-Activity Relationship; D001618:beta-Lactamases / Q000378:metabolism
D002511:Cephalosporins; D001618:beta-Lactamases