[Antibacterial in-vitro activity of pipemidic acid and nalidixic acid (author's transl)]

The in-vitro activity of nalidixic acid and pipemidic acid was investigated in a combined study in 450 freshly isolated bacterial strains using the agar dilution test. Gram-positive cocci were resistant to both substances except for a few pipemidic acid sensitive staphylococci. Both substances had good antibacterial activity in the gram-negative spectrum. However, the MIC values of pipemidic acid were generally clearly lower than those of nalidixic acid. Only pipemidic acid showed activity against Pseudomonas aeruginosa. Thus the in-vitro results showed that pipemidic acid has clear-cut and valuable advantages for the treatment of urinary tract infections when compared with nalidixic acid.