Antibacterial activity of nifuratel in urine and serum.

The minimum inhibitory concentrations of nifuratel for 205 randomly selected isolates from urinary tract infections were tested by tube dilution. Of these, 177 (86.3%) were resistant to more than 6 mug/ml and 140 of 141 (99.3%) strains of Escherichia coli were resistant to more than 3 mug/ml. Urine levels of nifuratel were examined in two groups: one group had 400 mg given once and the other group had 2 g given over 24 hours. In both groups samples of urine were collected every hour for seven hours after the last dose. After one 400-mg dose the maximum urine level achieved by any subject was 2.0 mug/ml and the mean maximum level was 0.75 mug/ml. With the 2 g total dose, the maximum level noted was 4 mug/ml and the mean maximum level was 1.8 mug/ml. No measurable inhibition was noted in any of the blood samples removed at one and a half to two hours after the last dose.