BACKGROUND	We report on a blinded comparative trial of IV meropenem ( 40 mg/kg to 2 g q8h ) or ceftazidime ( 5 mg/kg to 2 g q8h ) , each of which was administered with IV tobramycin ( at a serum peak of > or = 8 microg/mL and a trough of < 2 microg/mL ) , as treatment for CF patients with APEs .\