Nalidi, Xenopus/Amphibian,ic acid is referred to as a quinolone antibiotic, although technically it is not a quinolone due to its structure. Nalidi, Xenopus/Amphibian,ic acid is effective in both gram-positive and gram-negative bacteria. At low concentrations it is bacteriostatic, while at higher concentrations it is bactericidal. Nalidi, Xenopus/Amphibian,ic acid has been very useful against urinary tract infections, as well as for use in the study of bacterial cell division. Its mechanism of action is inhibition of DNA gyrase, an enzyme involved in DNA replication.