[Antibacterial activity of lomefloxacin in the urine during the 4 days following a single 400 mg oral dose].

Antibacterial activity of lomefloxacin was studied in the urine after single dose of 400 mg in ten healthy female volunteers. Urine was collected in 7 periods: 0-3 h, 3-6 h, 6-12 h, 12-24 h, 24-48 h, 48-72 h, 72-96 h. Lomefloxacin concentration were assayed in all samples by microbiological method. Urine antibacterial activity was determined towards five strains isolated in urine: 2 E. Coli strains one sensitive and the other resistant to nalidixic acid (Nal-A), 1 Klebsiella pneumoniae resistant to nalidixic acid (Nal-B), 1 Staphylococcus saprophyticus and 1 Streptococcus faecalis. MIC's of lomefloxacin against these strains were respectively 0.06, 0.50, 0.50, 0.25 and 4 micrograms/ml. Lomefloxacin mean concentrations were 208.5 +/- 44.2, 104.3 +/- 15.2, 100.5 +/- 17.9, 36.8 +/- 8.2, 9.6 +/- 2.2 micrograms/ml in the five first urine samples. Low levels were present in urine the 4th day. Mean urine elimination percentage was 62.2 +/- 4.2% for the four days, with extreme values from 91.2 to 41.8%. Urine bacteriostatic activity against enterobacteriacae was greater than or equal to 32 the first day reaching 8,192 for the Nal-S E. Coli, it was greater than or equal to 4 the second day. Against staphylococcus it was greater than or equal to 64 the first day, greater than or equal to 16 the second day. Against enterococcus it was greater than or equal to 4 the first day. Against the strains implicated in UTI a bacteriostatic activity was present during 2 days in all subjects.