title: [Detection of serinocarbapenemases Class A and other mechanisms of enzymatic resistance to β-lactams in enterobacteria strains with diminished susceptibility to carbapenems isolated of patients in a university hospital].
abstract: BACKGROUND
  The emergence of carbapenemase mediated resistance in Enterobacteriaceae has a strong clinical impact. This study aimed to do a genotypic and phenotypic characterization of the enzymatic resistance to β-lactams in clinical Enterobacteriaceae isolates with decreased susceptibility to carbapenems in a university medical center in Santiago.
  
  
  METHODS
  During April-September 2010 at Hospital Clinico Universidad de Chile, 23 isolates of carbapenem non susceptible Enterobacteriaceae were collected. We used PCR for the detection of class A carbapenemases (SME, IMI, NMC, GES and KPC) and the modified Hodge with the boronic acid test to phenotypically assess the presence of serine-carbapenemases. To assess extended spectrum β-lactamases (ESBLs) the CLSI phenotypic tests were performed. Metallo-β-lactamases (MBL) and AmpC were assessed with commercial tablets.
  
  
  RESULTS
  18/23 were Klebsiellapneumoniae and 5/23 strains were Enterobacter cloacae. All PCR to class A carbapenemases were negative. 3/23 strains (all E. cloacae), were positive to the Hodge modified test and 1/23, a K.pneumoniae, was positive to the boronic acid test. ESBLs were detected in 14/23 os the strains and AmpC in 5/23. No MBL was detected.
  
  
  CONCLUSIONS
  No class A serine-carbapenemasa was detected. The decreased susceptibility to carbapenems is probably explained by the β-lactamase activity and due to porin loss.
authors: Virginia de la
authors: Vde L
authors: Lastra
authors: Lina M
authors: LM
authors: Rivas
authors: Francisco
authors: F
authors: Silva
authors: M Teresa
authors: MT
authors: Ulloa
authors: M Eugenia
authors: ME
authors: Pinto
authors: Mario
authors: M
authors: Vidal
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D015780:Carbapenems / Q000494:pharmacology*; D002677:Chile; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D001618:beta-Lactamases / Q000235:genetics*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D047090:beta-Lactams; D001618:beta-Lactamases; C063912:carbapenemase