Effect of bismuth subcarbonate against Campylobacter pylori: do citrate ions improve antibacterial activity?

The minimum inhibitory concentrations of three bismuth subcarbonate preparations: 1. bismuth subcarbonate, 2. a mixture of 50% bismuth subcarbonate and 50% citric acid, 3. a mixture of 50% bismuth subcarbonate and 50% potassium citrate were assayed against 30 strains of Campylobacter pylori employing the agar dilution method. Bismuth subcarbonate alone exhibited an MIC50 of 2 mg/l and was more effective than the two combinations (MIC50 4 mg/l). It is concluded that the addition of citrate ions does not improve antibacterial activity.