[In vitro antibacterial activity of fleroxacin (FLRX) against clinical isolates from bacterial enteritis].

Antibacterial activity of fleroxacin (FLRX), a new quinolone antimicrobial, against 36 strains of Shigella app., 14 strains of Salmonella spp., 11 strains of Escherichia coli, 9 strains of Vibrio spp. (including 2 strains of V. cholerae O1), 14 strains of Campylobacter jejuni/coli, 3 strains of Aeromonas spp. and 1 strain of Plesiomonas shigelloides isolated from infectious enteritis patients in this study was determined. Its activity was compared with that of ciprofloxacin (CPFX), norfloxacin (NFLX) and nalidixic acid (NA). The MIC90 values of FLRX were 0.1 microgram/ml against Shigella spp. and E. coli, 0.2 microgram/ml against Salmonella spp. and Vibrio spp., and 12.5 micrograms/ml against C. jejuni/coli MIC90 of FLRX was comparable to that of CPFX and NFLX against Vibrio spp.. Against other species, MIC90 of FLRX were 2- to 4-fold higher than those of CPFX, whereas equal to or 2-fold lower than NFLX. FLRX demonstrated excellent activity against an NA-resistant (MIC: > 100 micrograms/ml) isolate of E. coli, with MIC 0.78 microgram/ml. FLRX showed 8-fold higher activity than NA against other strains. The antibacterial activity of FLRX was compared with that of NA against stocked strains (clinical isolates from August 1989 to February 1991), consisting of 11 strains of Shigella spp., 10 strains of Salmonella spp., 8 strains of E. coli, 10 strains of V. cholerae O1, 10 strains of V. parahaemolyticus and 14 strains of C. jejuni/coli. MICs of FLRX were 0.78 and 12.5-25 micrograms/ml against Shigella spp. and C. jejuni/coli that showed resistance of NA (MIC: > or = 100 micrograms/ml), respectively. Based on the above, although the absolute MICs are low against E. coli and shigella spp., a value of 0.78 micrograms/ml for FLRX suggested that such strains should be considered to be resistant.