[Bacteriostatic activity of azlocillin, gentamycin, amikacin singly or in combination on 200 strains of Pseudomonas aeruginosa].

In vitro activity of azlocillin, gentamicin, and amikacin, alone or in combination was evaluated against 200 clinical isolates of Pseudomonas aeruginosa. The minimum inhibitory concentrations (MICs) were determined by a standard technique. For the evaluation of synergistic activities, one antibiotic was added in a concentration equivalent to one-fourth its MIC to increasing concentrations of the other antibiotic. The MIC for 50% of the strains was 3.25 micrograms/ml for gentamicin, 3 micrograms/ml for amikacin and 7 micrograms/ml for azlocillin. No significant difference could be seen between the two combinations, the percentage of synergy was 37% for azlocillin-gentamicin and 36% for azlocillin-amikacin. No antagonism was observed.