[Value of bactericidal curves in the optimal selection of a beta-lactam-aminoglycoside combination on Pseudomonas aeruginosa. In vitro study of 40 strains of Pseudomonas aeruginosa isolated in pediatric intensive care units].

Antimicrobial sensitivity and time-kill curves were determined for ticarcillin, azlocillin, piperacillin, cefsulodin, ceftazidime, gentamicin, tobramycin and amikacin alone or in combination against 40 strains of Pseudomonas aeruginosa isolated from blood cultures and tracheal aspirates in pediatric intensive care units. The antibiotics were used in concentrations obtainable with the usual therapeutic dosage. No bactericidal effect was observed with each of the beta-lactam antibiotics tested alone. For ticarcillin-sensitive strains the most rapid bacterial inoculum size decrease was observed at 2.5 h with the piperacillin-amikacin combination, and a bactericidal effect was obtained within 4.5 h when amikacin was combined with ticarcillin, azlocillin, piperacillin, ceftazidime or cefsulodin. For ticarcillin-resistant strains a bactericidal effect was obtained within 4.5 h when amikacin was combined with piperacillin, azlocillin, ceftazidime or cefsulodin.