Effects of Single Oral Doses of Gemifloxacin (320 Milligrams) versus Trovafloxacin (200 Milligrams) on Fecal Flora in Healthy Volunteers

Gemifloxacin and trovafloxacin were administered to 12 volunteers in a randomized crossover trial with a 2-week washout period. Stool samples were collected predose and 1, 2, and 3 days postdose. Both quinolones reduced the number of organisms of the family Enterobacteriaceae and aerobic gram-positive organisms. Escherichia coli reduction was greater with gemifloxacin than with trovafloxacin, with postdose isolation of quinolone-resistant strains for which MICs of trovafloxacin were higher than those of gemifloxacin.