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Antimicrobial Agents and Chemotherapy, July 1998, p. 1659-1665, Vol. 42, No. 7
Department of Urology,
Received 22 July 1996/Returned for modification 30 December
1996/Accepted 27 April 1998
Twelve healthy volunteers participated in this randomized crossover
study to compare the concentrations and recovery levels of fleroxacin
and pefloxacin in urine and to assess their bactericidal activities
against 12 strains of urinary pathogens with different susceptibilities
over a wide range of MICs. The volunteers received a single oral dose
of 400 mg of fleroxacin or 800 mg of pefloxacin. The mean cumulative
renal excretion of unchanged fleroxacin,
N-demethyl-fleroxacin, and N-oxide-fleroxacin
accounted for 67, 7, and 6% of the total dose, respectively. The total
urinary recovery of pefloxacin and the active metabolite norfloxacin
was 34%. In the time-kill and the urinary bactericidal titer (UBT)
studies, only the subjects' urine not supplemented with broth was
used. With most tested organisms and both quinolones it took more than
8 h to achieve a reduction in CFU of 99.9% (3 log units).
Overall, there was a good correlation between UBTs and MICs for the
strains. Against Escherichia coli ATCC 25922 the median
UBTs were similar for both antibiotics and at least 1:8 for 96 h;
against the E. coli strain for which the MIC was 0.5 µg/ml the UBT was at least 1:4 for 48 h. The UBTs of both drugs
against Klebsiella pneumoniae were at least 1:16 for
72 h. The UBTs for Staphylococcus aureus (the MIC for
which was 16 µg/ml) of both antibiotics were low, and in some of the samples, no bactericidal titers were observed. UBTs for Proteus mirabilis of pefloxacin are significantly higher than those of fleroxacin. For Pseudomonas aeruginosa the median UBTs were
present for the 24-to-48-h interval. The same is true for
Enterococcus faecalis. Against Staphylococcus
saprophyticus, UBTs were present for at least 48 h with both
quinolones. Overall, a single oral dose of 400 mg of fleroxacin
exhibits UBTs comparable to those of 800 mg of pefloxacin. Therefore,
it may be expected that half of the dose of fleroxacin gives comparable
results in the treatment of urinary tract infections; this should be
substantiated in comparative clinical trials.
0066-4804/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Urinary Excretion and Bactericidal Activities of a Single Oral
Dose of 400 Milligrams of Fleroxacin versus a Single Oral Dose of
800 Milligrams of Pefloxacin in Healthy Volunteers
*
Corresponding author. Mailing address: Department of
Urology, St. Elisabeth Hospital, St. Elisabethstr. 23, D-94315
Straubing, Germany. Phone: (9421) 710 1700. Fax: (9421) 710 270.
Antimicrobial Agents and Chemotherapy, July 1998, p. 1659-1665, Vol. 42, No. 7
0066-4804/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
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