title: [Comparative activity of ertapenem against extended-spectrum beta-lactamase-producing or plasmid-mediated AmpC beta-lactamase-producing Klebsiella pneumoniae].
abstract: BACKGROUND
  The effect of porin loss and inoculum size on the comparative activity of ertapenem against either extended-spectrum beta lactamase-producing (ESBL) or plasmid-mediated AmpC beta lactamase-producing (pACBL) Klebsiella pneumoniae strains was evaluated.
  
  
  METHODS
  Microdilution using 2 different bacterial inocula.
  
  
  RESULTS
  Imipenem, amikacin, ertapenem, and cefepime were the most active agents under standard conditions. Ertapenem was more highly affected by porin loss than imipenem.
  
  
  CONCLUSIONS
  Ertapenem showed high activity against K. pneumoniae strains expressing ESBL, pACBL or both. Strains deficient in porins showed decreased susceptibility to beta lactams. The inoculum effect had a greater impact on imipenem than on ertapenem.
authors.affiliation: Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Sevilla, España. joserhb@us.es
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Hernández
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Conejo
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual
mesh_terms: D000583:Amikacin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D000077723:Cefepime; D002511:Cephalosporins / Q000494:pharmacology; D000077727:Ertapenem; D015378:Imipenem / Q000494:pharmacology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D008826:Microbial Sensitivity Tests; D018272:Porins / Q000172:deficiency; D011815:R Factors / Q000235:genetics; D013379:Substrate Specificity; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002511:Cephalosporins; C119261:OmpK35 porin, Klebsiella pneumoniae; C092233:OmpK36 protein, Klebsiella pneumoniae; D018272:Porins; D047090:beta-Lactams; D015378:Imipenem; D000077723:Cefepime; D000583:Amikacin; C048795:AmpC beta-lactamases; D001618:beta-Lactamases; D000077727:Ertapenem