title: In vitro activity of ciprofloxacin, norfloxacin and nalidixic acid.
abstract: The in vitro antibacterial activity of the new quinoline derivative ciprofloxacin (BAY 0 9867) was evaluated in comparison to norfloxacin and nalidixic acid using 495 clinical strains of gram-negative and gram-positive bacteria. The compound was highly active against Enterobacteriaceae, with MICs ranging from 0.008 mg/l to 4 mg/l, whereas the MICs of norfloxacin ranged from 0.03 mg/l to 16 mg/l. All strains of Pseudomonas aeruginosa and Acinetobacter calcoaceticus were inhibited with a concentration of 2 mg/l ciprofloxacin and 32 mg/l norfloxacin. Ciprofloxacin was also active against gram-positive cocci. The MICs for Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus faecalis ranged from 0.008 to 2.0 mg/l. The activity of ciprofloxacin was only slightly influenced by inoculum size, whereas an acid environment caused a noticeable decrease in the activity. Ciprofloxacin would seem to be a promising antibacterial agent for the treatment of urinary tract infection.
mesh_terms: D000892:Anti-Infective Agents, Urinary / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002939:Ciprofloxacin; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D009643:Norfloxacin; D011804:Quinolines / Q000494:pharmacology*
chemical_list: D000892:Anti-Infective Agents, Urinary; D011804:Quinolines; D009268:Nalidixic Acid; D002939:Ciprofloxacin; D009643:Norfloxacin