E-TEST TO STUDY STRAINS OF PSEUDOMONAS-AE RUGINOSA AND ACINETOBACTER-BAUMANII ASSOCIATED TO NOSOCOMIAL INFECTIONS

Background: Pseudomonas aeruginosa and Acinetobacter baumanii are two important nosocomial agents that require permanent testing of their an timicrobial susceptibility. Aim: To use E-test to determine minimal in hibitory concentrations, estimate bacterial diversity and presumably i dentify B-lactamases of strains of Pseudomonas aeruginosa and Acinetob acter baumanii isolated from nosocomial infections. Materials and meth ods: Sixty eight strains of Pseudomonas aeruginosa and Acetinobacter b aumanii isolated in a teaching hospital were analyzed with E-test stri ps to determine their minimal inhibitory concentrations for different antimicrobials. Results: More than 75% of Acinetobacter baumanii were resistant to Piperacillin, Cefpirone, Cefepime, Gentamicin or Amikacin , 40% of strains were resistant to ceftazidine, 27 and 53% of of isola tes had a decreased susceptibility to Meropenem and Piperacillin-tazob actan respectively. Twenty eight to 54% of Pseudomonas aeruginosa stra ins were resistant to Cefepime, Cefpirome, Ciproflaxacin and Gentamici n. Eighteen and 10% of strains were resistant to Meropenem and Imipene m respectively. Less than 10% of strains were resistant to Amikacin, A ztreonam, Piperacillin-tazobactam or Ceftazidime. Most of beta-lactam resistance of Pseudomonas aeruginosa was associated to decreased susce ptibility or resistence to Cefpirome, Cefepime or to Meropenem-Imipene m and did not match clearly with known beta-lactamase profiles. Conclu sions: The knowledge of susceptibility of these bacteria responsible f or nosocomial infections, will help to plan the appropriate use of ant imicrobials.