title: [E-test to study small inhibitor concentrations, bacterial diversity and to identify presumptively beta-lactamases in strains of Pseudomonas aeruginosa and Acinetobacter baumannii associated with +nosocomial infections].
abstract: BACKGROUND
  Pseudomonas aeruginosa and Acinetobacter baumanii are two important nosocomial agents that require permanent testing of their antimicrobial susceptibility.
  
  
  OBJECTIVE
  To use E-test to determine minimal inhibitory concentrations, estimate bacterial diversity and presumably identify B-lactamases of strains of Pseudomonas aeruginosa and Acinetobacter baumanii isolated from nosocomial infections.
  
  
  METHODS
  Sixty eight strains of Pseudomonas aeruginosa and Acinetobacter baumanii isolated in a teaching hospital were analyzed with E-test strips to determine their minimal inhibitory concentrations for different antimicrobials.
  
  
  RESULTS
  More than 75% of Acinetobacter baumanii were resistant to Piperacillin, Cefpirome, Cefepime, Gentamicin or Amikacin, 40% of strains were resistant to Ceftazidime, 27 and 53% of isolates had a decreased susceptibility to Meropenem and Piperacillin-tazobactam respectively. Twenty eight to 54% of Pseudomonas aeruginosa strains were resistant to Cefepime, Cefpirome, Ciprofloxacin and Gentamicin. Eighteen and 10% of strains were resistant to Meropenem and Imipenem respectively. Less than 10% of strains were resistant to Amikacin, Azireonam, Piperacillin-tazobactam or Ceftazidime. Most of beta-lactam resistance of Pseudomonas aeruginosa was associated to decreased susceptibility or resistance to Cefpirome, Cefepime or to Meropenem-Imipenem and did not match clearly with known beta-lactamase profiles.
  
  
  CONCLUSIONS
  The knowledge of susceptibility of these bacteria responsible for nosocomial infections, will help to plan the appropriate use of antimicrobials.
authors.affiliation: Departamento de Medicina, Hospital II Aguirre, Santiago de Chile.
authors.forename: V
authors.initials: V
authors.lastname: Triantafilo
authors.forename: A
authors.initials: A
authors.lastname: Fica
authors.forename: M
authors.initials: M
authors.lastname: Silva
authors.forename: L
authors.initials: L
authors.lastname: Thompson
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases