Mecillinam versus cephaloridine for the treatment of acute pyelonephritis

Patients with acute pyelonephritis were randomly assigned to treatment with 0.8 g of mecillinam (n=25) or 1 g of cephaloridine (n=26) i. v. three times daily. Urinary cultures were negative in all patients after two days of treatment. Although the isolated organisms were sensitivein vitro to mecillinam, the clinical response to mecillinam was poor in seven out of 25 patients, as compared to one out of 26 patients treated with cephaloridine (p<0.05).