In-vitro activity of enoxacin, ofloxacin, norfloxacin and nalidixic acid.

The in-vitro activity of enoxacin, ofloxacin, norfloxacin and nalidixic acid was determined against 1499 Gram-negative and 279 Gram-positive isolates from different clinical institutions in the Federal Republic of Germany. 90% of all Enterobacteriaceae were inhibited by 0.5 mg/l. Glucose non-fermenting Gram-negative rods and staphylococci were less sensitive to all 4-quinolones. All Gram-negative strains selected for resistance to nalidixic acid were significantly less sensitive to the new generation of 4-quinolones tested.