title: [Characterization of isolates of carbapenemase-producing Pseudomonas aeruginosa from seven Colombian provinces].
abstract: BACKGROUND
  Pseudomonas aeruginosa is an opportunistic pathogen that causes multiple infections in hospitalized patients. This microorganism has developed resistance to several antimicrobial agents, including carbapenems, which are considered to be the last therapeutic option against these infections. Carbapenem resistance of P. aeruginosa is mediated by different mechanisms: Carbapenemases class B (MBL) and A, alterations in the OprD expression and overexpression of the Mex efflux pump.
  
  
  OBJECTIVE
  To describe the presence of carbapenemases in P. aeruginosa isolates from seven Colombian provinces.
  
  
  METHODS
  A total of 57 P. aeruginosa isolates were collected between September 2012 and March 2013 from national surveillance in Colombia and were sent to the Grupo de Microbiología at the Instituto Nacional de Salud (INS) for evaluation. Iidentification and antimicrobial susceptibility were confirmed through automated method (Vitek ® 2) and disk diffusion (Kirby-Bauer) according to the Clinical and Laboratory Standards Institute, CLSI, 2013. Phenotypic and genotypic confirmation was determined using the modified Hodge test (MHT), a synergism test using imipenem, EDTA-SMA and meropenem, and conventional PCR to detect the bla KPC, bla VIM, bla IMP and bla NDM genes.
  
  
  RESULTS
  Of the 57 isolates, two showed sensitivity to carbapenems. Forty-three isolates were positive for carbapenemases with a high percentage of sensitivity to colistin (76.4%, n=42). The 43 isolates producing carbapenemases showed multiple drug resistance: 72.1% were positive in the MHT and 79.1% showed MBL synergism. PCR amplification confirmed that 33 isolates were positive for bla VIM, nine were positive for bla KPC and one isolate expressed both KPC and VIM carbapenemases. No isolates showed amplified products with bla IMP and bla NDM primers.
  
  
  CONCLUSIONS
  The most frequent carbapenemase was VIM, followed by KPC in an approximate ratio of 3:1.
authors: Grupo de Microbiología, Dirección de Redes en Salud Pública, Subdirección Laboratorio Nacional de Referencia, Instituto Nacional de Salud.
authors: Sandra Yamile
authors: SY
authors: Saavedra
authors: Grupo de Microbiología, Dirección de Redes en Salud Pública, Subdirección Laboratorio Nacional de Referencia, Instituto Nacional de Salud.
authors: Carolina
authors: C
authors: Duarte
authors: Grupo de Microbiología, Dirección de Redes en Salud Pública, Subdirección Laboratorio Nacional de Referencia, Instituto Nacional de Salud.
authors: María Nilse
authors: MN
authors: González
authors: Grupo de Microbiología, Dirección de Redes en Salud Pública, Subdirección Laboratorio Nacional de Referencia, Instituto Nacional de Salud.
authors: María Elena
authors: ME
authors: Realpe
mesh_terms: D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D003105:Colombia / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D005838:Genotype; D006801:Humans; D010641:Phenotype; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D015163:Superinfection; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase