title: [Detection of extended spectrum β-lactamase OXA-141 in Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis].
abstract: BACKGROUND
  The aims of this research were to study the presence of extended spectrum β-lactamases (ESBL) to investigate the location of the genes encoding these enzymes, and determine the clonal relationship of strains of ceftazidime-resistant Pseudomonas aeruginosa isolated from Mexican patients with cystic fibrosis.
  
  
  METHODS
  We determined the resistance profile to 11 antibiotics (CLSI) and phenotypic ESBL detection following a disk diffusion method adapted for P. aeruginosa. Characterization of ESBL genes and integrons was performed by polymerase chain reaction (PCR) and DNA sequencing, while analysis of the clonal relationship was performed by pulsed field gel electrophoresis (PFGE).
  
  
  RESULTS
  Of the 148 strains studied, 22 were resistant to ceftazidime, and analysis by PCR and sequencing revealed the presence of the gene bla(OXA-141) in 7 strains, 6 of which were resistant and one, susceptible to ceftazidime. In addition, bla(GES) was detected in 11 strains. intI2 and intI3 genes were not detected by PCR, but in the 6 ceftazidime-resistant strains, the bla(OXA-141) gene was determined in a class 1 integron. Analysis of the clonal relationship of isolates showed that the majority of patients were infected during the study period with P. aeruginosa strains that exhibit different patterns, especially in individuals without a familial relationship.
  
  
  CONCLUSIONS
  This report demonstrates the existence of the bla(OXA-141) gene associated with a class 1 integron in several strains of P. aeruginosa, as well as bla(GES) genes, and their location and variants are being studied by our research group. This, combined with the diversity of strains able to infect several susceptible individuals, suggests the risk of spread of P. aeruginosa-strain ESBL producers among Mexican populations with cystic fibrosis.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México D.F., México.
authors.forename: Maribel
authors.initials: M
authors.lastname: González-Villa
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Ribas-Aparicio
authors.forename: Rafael
authors.initials: R
authors.lastname: Coria-Jiménez
authors.forename: Jenny Elizabeth
authors.initials: JE
authors.lastname: Donis-Rocandio
authors.forename: Gerardo
authors.initials: G
authors.lastname: Aparicio-Ozores
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000032:analysis*; D002442:Ceftazidime / Q000494:pharmacology*; D003550:Cystic Fibrosis / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002442:Ceftazidime; D001618:beta-Lactamases; C584657:beta-lactamase OXA-141, Pseudomonas aeruginosa