title: [Resistance to imipenem in Enterobacter aerogenes].
abstract: BACKGROUND
  In June, 1993, an Enterobacter aerogenes strain was isolated in the Hospital de la Creu Roja from Hospitalet de Llobregat (Barcelona), which was resistant against all beta-lactams, including imipenem. Since is unusual in Enterobacter sp. to isolate imipenem resistant strains, we decided to study its resistance mechanism.
  
  
  METHODS
  To study the E. aerogenes 174004/H resistance mechanism beta-lactamase isoelectrofocalization was performed together with the determination of kinetic constants in order to characterize the beta-lactamase, and a polyacrylamide gel electrophoresis in order to observe the profile.
  
  
  RESULTS
  The strain of E. aerogenes 174004/H exhibits a chromosomic beta-lactamase with a pI higher than 9.2 and a decrease in an outer membrane protein of 42 kDa, probably a porine.
  
  
  CONCLUSIONS
  E. aerogenes 174004/H resistance against imipenem is due to an hyperproduction of a chromosomic beta-lactamase with a pI higher than 9.2 and to a 42 kDa decrease of an outer membrane protein expression.
authors.affiliation: Servicio de Microbiología, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma, Barcelona.
authors.forename: E
authors.initials: E
authors.lastname: Miró
authors.forename: C
authors.initials: C
authors.lastname: Alonso
authors.forename: F
authors.initials: F
authors.lastname: Navarro
authors.forename: B
authors.initials: B
authors.lastname: Mirelis
authors.forename: G
authors.initials: G
authors.lastname: Prats
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D004754:Enterobacter / Q000737:chemistry / Q000187:drug effects*; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000032:analysis
chemical_list: D001425:Bacterial Outer Membrane Proteins; D015378:Imipenem; D001618:beta-Lactamases
vernacular_title: Resistencia al imipenem en Enterobacter aerogenes.