Activity of disulfiram (bis(diethylthiocarbamoyl)disulphide) and ditiocarb (diethyldithiocarbamate) against metronidazole-sensitive and -resistant Trichomonas vaginalis and Tritrichomonas foetus

Clinical resistance of Trichomonas vaginalis to metronidazole is best correlated with MIC values measured under aerobic conditions. Under these conditions both disulfiram (bis(diethylthiocarbamoyl)disulphide), and its first mammalian metabolite, ditiocarb (diethyldithiocarbamate), showed high levels of activity against metronidazole-sensitive (disulfiram MIC, 0.1-0.7 μM; ditiocarb MIC, 0.3-9 μM) and -resistant (MICs 0.2-1.3 μM and 1.2-9 μM respectively) isolates. Tritrichomonas foetus was also sensitive - the MICs for seven metronidazole-sensitive isolates were 0.1-1.0 μM for disulfiram and 1.0-6.9 μM for ditiocarb; those for two highly metronidazole-resistant strains were 0.3-1.3 μM and 0.6-6 μM respectively. Under anerobic conditions most strains became highly resistant to both compounds. Surprisingly, disulfiram was consistently more active than ditiocarb.