title: Unusual diversity of acquired β-lactamases in multidrug-resistant Pseudomonas aeruginosa isolates in a Mexican hospital.
abstract: OBJECTIVE
  To investigate the presence of extended spectrum and metallo β-lactamases (MBLs) in Pseudomonas aeruginosa isolates which are resistant to imipenem and ceftazidime that were isolated in a hospital in Mexico.
  
  
  RESULTS
  Pulsed-field gel electrophoresis (PFGE) revealed the presence of four clonal types among the 14 isolates. All these genes were found either alone or simultaneously in the P. aeruginosa strains in the following five different arrangements: <bla(GES-5)>; <bla(GES-5), bla(VIM-11)>; <bla(GES-5), bla(VIM-2), bla(VIM-11)>; <bla(GES-5), bla(OXA-2)>; and <bla(GES-5), bla(VIM-2), bla(VIM-11), and bla(OXA-2)>. Class 1 integrons were detected and contained the cassettes bla(GES-5) and bla(OXA-2), but not that of bla(VIM). bla(VIM) genes occurred only in the chromosome, while bla(GES-5) was located in the chromosome and in the plasmids.
  
  
  CONCLUSIONS
  To our knowledge, this is the first description of P. aeruginosa strains simultaneously producing the VIM-2 and VIM-11 variants, and the combination of GES-5 and MBL carbapenemases, which determines a major challenge for the clinical microbiology laboratory and a remarkable epidemiological risk for the nosocomial spread of multidrug-resistant determinants.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico.
authors.forename: Jane
authors.initials: J
authors.lastname: Castillo-Vera
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Ribas-Aparicio
authors.forename: Carlos Juan
authors.initials: CJ
authors.lastname: Nicolau
authors.forename: Antonio
authors.initials: A
authors.lastname: Oliver
authors.forename: Lourdes
authors.initials: L
authors.lastname: Osorio-Carranza
authors.forename: Gerardo
authors.initials: G
authors.lastname: Aparicio-Ozores
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D032023:Integrons / Q000235:genetics; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D001618:beta-Lactamases / Q000145:classification* / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C425108:beta-lactamase bla(vim-2); D001618:beta-Lactamases; C540661:beta-lactamase VIM-11, Pseudomonas aeruginosa; C063912:carbapenemase