Norfloxacin: in vitro activity compared with that of seven other antibacterial agents against urinary tract pathogens.

The minimal inhibitory concentrations (MICs) of norfloxacin, nalidixic acid, ampicillin, amoxycillin/clavulanic acid (4:1), mecillinam, cefaclor , sulphamethoxazole/trimethoprim (20:1) and netilmicin against 435 clinical isolates of bacterial urinary tract pathogens have been determined. An agar dilution method was employed. Norfloxacin was the most active agent in the study on a weight-for-weight basis. The drug was highly active against Enterobacteriaceae. Norfloxacin was more active than netilmicin against Pseudomonas aeruginosa (MICs less than or equal to 2 mg/l and less than or equal to 4 mg/l, respectively). Norfloxacin was also active against Gram-positive bacteria including enterococci and Staphylococcus saprophyticus (MICs less than or equal to 4 mg/l). Norfloxacin may well become a useful agent for the oral treatment of urinary tract infection, particularly as a drug for the treatment of infections caused by multiresistant organisms.