ANTIBACTERIAL ACTIVITY OF CIPROFLOXACIN I N THE URINE DURING 4 DAYS AFTER A SINGLE 500 MG AND 750 MG ORAL DOSE

Antibacterial activity of ciprofloxacin was studied in the urine after a single 500 mg and 750 mg oral dose in ten healthy female volunteers . Urine was collected, after each single oral dose, during seven time periods : 0-3 h, 3-6 h, 6-12 h, 12-24 h, 24-48 h, 48-72 h , 72-96 h. C iprofloxacin concentrations were assayed by microbiological method. Ur ine antibacterial activity was determined for five bacterial strains i solated in urine : 2 E. coli strains, one sensitive and the other resi stant to nalidixic acid (Nal-A), 1 Klebsiella pneumoniae resistant to nalidixic acid (Nal.B), 1 Staphylococcus saprophyticus and 1 Enterococ cusfaecalis. MICs of ciprofloxacin against these strains were respecti vely 0.003, 0.06, 0.25, 0.06 and 0.5 mug/ml. Ciprofloxacin mean concen trations in the seven urine samples were 292.5 +/- 55.8, 81.1 +/- 16.9 , 43.7 +/- 11.6, 11.5 +/- 1.9, 1.3 +/- 0.2, 0.3 +/- 0.05 et 0.1 +/- 0. 05 mug/ml after a single 500 mg oral dose and 215.1 +/- 68.1, 56.1 +/- 17.8, 43 +/- 8.8, 14.4 +/- 5.5, 1.4 +/- 0.2, 0.4 +/- 0.1 and 0.2 +/- 0.05 mug/ml after a single 750 mg oral dose. Urine bacteriostatic acti vity was not very different after a 500 mg dose and a 750 mg dose. Aga inst enterobacteriacae, after a 500 mg dose it was greater-than-or-equ al-to 16 the first day; it was greater-than-or-equal-to 512 for the Na l-S E. coli. It was greater-than-or-equal-to 64 the first day, and rem ained between 2 and 32 the second day for the Nal-R strains (E. coli a nd Klebsiella). During the first day, it was greater-than-or-equal-to 64 against Staphylococcus saprophyticus and was greater-than-or-equal- to 8 against the Enterococcus faecalis strain. After a 750 mg dose, ur ine bacteriostatic activity against enterobacteriacae was greater-than -or-equal-to 16 the first day, reaching 8192 for the Nal-S E. coli. It was greater-than-or-equal-to 16 the first day, and remained between 2 and 32 the second day for the Nal-R strains (E. coli and Klebsiella). During the first day, it was greater-than-or-equal-to 32 and greater- than-or-equal-to 8 against respectively the S. saprophyticus and Enter ococcusfaecalis strains.