Comparison of cefpiramide (HR-810) and four anti-pseudomonal beta-lactam agents against pseudomonas isolates from children with cystic fibrosis.

Cefpiramide (HR-810), ceftazidime, piperacillin, ticarcillin, and aztreonam were tested against tobramycin-sensitive and -resistant strains of Pseudomonas aeruginosa and tobramycin/amikacin-resistant isolates of Ps. cepacia recovered from the sputum of patients with cystic fibrosis. Against Ps. aeruginosa, none of the drugs inhibited 90% of the test strains at levels of less than 128 mg/l. Median minimal, inhibitory concentrations (MIC50) for all of the beta-lactam agents were lower for tobramycin-sensitive versus tobramycin-resistant isolates of Ps. aeruginosa. Ceftazidime was the most effective agent against Ps. cepacia. Aminoglycoside-resistance appears to be associated with significant beta-lactam resistance in Ps. aeruginosa isolated from the sputum of patients with cystic fibrosis.