Laboratory and clinical study of balofloxacin, a new fluoloquinolone, in urinary tract infection

Balofloxacin (BLFX), one of the newer quinolones, was investigated for its in vitro activity, diffusion into prostatic fluid (PF) and clinical efficacy in the treatment of urinary tract infection (UTI). The results obtained were as follows. 1. In vitro activity: Against 80 strains of Enterococcus faecalis isolated from UTI, the MIC of BLFX ranged from 0.20˜25 μg/ml, and the MIC₅₀and MIC₉₀ were 0.78 μg/ml and 12.5 ƒÊg/ml, respectively, roughly comparable to sparfloxacin. The drug appeared to be superior to other reference drugs such as norfloxacin, ofloxacin and ciprofloxacin. However, BLFX was less potent against 50 strains of Pseudomonas aeruginosa, for which the MIC₅₀ and MIC₉₀ were as much as 25 μg/ml and > 100 μg/ml.