Comparative evaluation of in vitro activity of different combinations of new B-lactam antimicrobial agents and amikacin against pseudomonas aeruginosa using the checkerboard titration technique

ABSTRACT

In vitro activities of antibiotic combinations containing amikacin and either piperacillin, aztreonam, ceftazidime, imipenem, or cefsulodin were evaluated by the checkerboard broth dilution method in 96-well microtiter plates. A total of 100 strains of Ps. Aeruginosa were tested. All drugs were tested in serial dilutions ranging from 250 to 3.9 mug/ml against standardized inoculum of 108 cells/ml of the bacterial suspension. Results showed that newer beta-lactams with antipseudomonal activity [as cefsulodin, piperacillin and aztreonam] in combination with amikacin are effective combination regimens against clinical isolates of Ps. aeruginosa and may be useful for empirical management of patients with serious Ps. Aeruginosa infection