Resumo

SIERRA R, Carmen I; GUEVARA, Esmirna  e  GUEVARA-PATINO, Armando. In vitro piperacillin-tazobactam activity in combination with aminoglycosides and fluoroquinolones in Pseudomonas aeruginosa metallo-β-lactamases producers. Rev. Soc. Ven. Microbiol. [online]. 2011, vol.31, n.1, pp.13-19. ISSN 1315-2556.

Pseudomonas aeruginosa is a gram negative bacillus able to acquire genes which codify for production of metallo-β-lactamases (MBL) becoming multiresistant, which difficults the treatment of infections produced by this microorganism. The in vitro activity of piperacilline-tazobactam, in combination with aminoglycosides and fluoroquinonolones was evaluated in 8 P. aeruginosa MBL producers obtained at four hospitals of the west and south areas of Venezuela through an epsilometric method. The antimicrobial combinations which showed the greatest synergic effect were piperacillin-tazobactam/gentamicin and piperacillin-tazobactam/amikacin in 5/8 isolates. The piperacilline-tazobactam/amikacin combination showed synergy in 4 cases and addition in the other 4, with the lowest index of mean fractionated inhibitory concentration. There was no antagonism in any of the antimicrobial combinations. The results of this study suggest that piperacilline-tazobactam in combination with gentamicin, amikacin or ciprofloxacin, could be used as therapeutic alternatives in multiresistant P. aeruginosa MBL producers at all the hospitals of Bolivar State, while in hospitals located in the west of Venezuela, the piperacilline-tazobactan/amikacin combination is suggested.

Palavras-chave : Pseudomonas aeruginosa; metallo-ß-lactamases; synergy; antimicrobial combinations; susceptibility to antimicrobials.