Comparative in vitro activities of niridazole and metronidazole against anaerobic and microaerophilic bacteria

In vitro susceptibilities of anaerobic bacteria (Bacteroides spp., Fusobacterium spp., Clostridium spp., and Peptococcus sp.) and of Campylobacter jejuni and C. coli to niridazole and metronidazole were determined. The minimum inhibitory concentrations for niridazole ranged from 0.0037 to 1.0 microgram/ml and, for metronidazole, from 0.25 to 128 micrograms/ml.