Comparative in-vitro activity of ciprofloxacin against non-fermenters

The in-vitro activity of ciprofloxacin, a quinolone-carboxylic acid derivative, was compared with those of carbenicillin, azlocillin, cefsulodin, ceftazidime, tobramycin and amikacin against 187 non-fermenters. Only one of the 131 strains of Pseudomonas spp. was not inhibited by 1 mg/l of ciprofloxacin, while these isolates appeared highly resistant to carbenicillin, azlocillin and cefsulodin. Ciprofloxacin was also the best agent against Flavobacterium, Alcaligenes faecalis and Acinetobacter calcoaceticus with MIC90's respectively of 0.5, 4 and 8 mg/l. This new compound appeared bactericidal, and we found a small or no inoculum effect with ciprofloxacin.