Bactericidal activity of gatifloxacin (AM-1155) against Pseudomonas aeruginosa and Enterococcus faecalis in an in vitro bladder model simulating human urinary concentrations after oral administration
S. Takahashi et al., Bactericidal activity of gatifloxacin (AM-1155) against Pseudomonas aeruginosa and Enterococcus faecalis in an in vitro bladder model simulating human urinary concentrations after oral administration, CHEMOTHERA, 46(2), 2000, pp. 122-128
The bactericidal activity of gatifloxacin, a new 6-fluoro-8-methoxy quinolo
ne, was determined in a dynamic in vitro model mimicking complicated lower
urinary tract infection. Strains of Pseudomonas aeruginosa and Enterococcus
faecalis with different susceptibility were exposed to changing gatifloxac
in concentrations, simulating human urinary concentrations afer oral treatm
ent with 200 mg twice daily for 3 consecutive days. Bacterial numbers of P.
aeruginosa (minimal inhibitory concentrations, MIG: less than or equal to
32 mu g/ml) and of E. faecalis (MIC: 16 mu g/ml) were reduced to undetectab
le levels during exposure. For the strains with lower susceptibility, gatif
loxacin showed bactericidal activity, but eradication was not complete. Thu
s, in a complicated urinary tract infection model, breakpoint MICs of gatif
loxacin for uropathogenic organisms were presumed to range from 16 to 32 mu
g/ml. At least 86% of recent clinical isolates of P. aeruginosa and E. fae
calis were inhibited at its breakpoint MIG. These results suggest that gati
floxacin may be useful in the treatment of urinary tract infections. Copyri
ght (C) 2000 S.Karger AG, Basel.