Influence of efflux pump inhibitors on the multidrug resistance ofHelicobacter pylori

AIM:To evaluate the effect of efflux pump inhibitors (EPIs) on multidrug resistance of Helicobacter pylori (H.pylori ).METHODS: H. pylori strains were isolated and cultured on Brucella agar plates with 10% sheep's blood.The multidrug resistant (MDR) H. pylori were obtained with the inducer chloramphenicol by repeated doubling of the concentration until no colony was seen, then the susceptibilities of the MDR strains and their parents to 9 antibiotics were assessed with agar dilution tests.The present study included periods before and after the advent of the EPIs, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), reserpine and pantoprazole), and the minimum inhibitory concentrations (MICs) were determined accordingly.In the same way, the effects of 5 proton pump inhibitors (PPIs), used in treatment of H. pylori infection, on MICs of antibiotics were evaluated. RESULTS:Four strains of MDR H. pylori were induced successfully, and the antibiotic susceptibilities of MDR strains were partly restored by CCCP and pantoprazole, but there was little effect of reserpine.Rabeprazole was the most effective of the 5 PPIs which could decrease the MICs of antibiotics for MDR H. pylori significantly. CONCLUSION:In vitro , some EPIs can strengthen the activities of different antibiotics which are the putative substrates of the efflux pump system in H. pylori .