Antibacterial effects of niridazole: its effect on microaerophilic campylobacter.

Niridazole, a nitrothiazole derivative, exhibited marked antimicrobial activity against a group of microaerophilic campylobacter. MICs ranged from 0.0037 to 2.0 mg/l, with an average of 0.25 mg/l. The activity of niridazole was compared to that of chemically related compounds (metronidazole, ornidazole, tinidazole). Although their activities ran parallel, niridazole was found to be markedly more potent. Thirteen other common antibiotics were also inferior to niridazole with respect to their inhibitory effect. The antibacterial activity of niridazole was bactericidal. Its in vivo activity was also tested in mice infected orally with campylobacter. The organisms, which caused a chronic colonization of the gut in untreated animals, disappeared rapidly from the faeces after treatment with niridazole, at least in the case of a highly susceptible campylobacter strain.