Proton pump inhibitors (PPIs) have been used with antibiotic for treatment of H. pylori infection. PPIs have negative effects on H. pylori growth. Target molecules of these drugs have not been identified. PPIs with lipophilic nature probably interact with components of H. pylori cell membrane. The aim of this study was examine the effect of PPIs on H. pylori growth and viability by LIVE/DEAD kit emphasis on cell membrane

One H. pylori isolate from dyspeptic patients was cultivated in brain heart infusion (BHI) broth supplemented with 2.5% horse serum and pantoprazole (PAN 128 µg/mL). After 24 h, 1 mL of bacterial culture washed twice with PBS 1X and was resuspended in 300 μl of PBS. A 50- µL of harvested cells was cultured on Brucella blood agar (BBA), incubated in microaerophilic condition at 37⁰C to examine culturability up to 7 days. A 200-µL were stained with LIVE/DEAD kit to check the viability of treated bacteria. Also pure PPI was stained. Stained samples were examined by fluoresce microscopy. Untreated sample was used as control.

Control H. pylori growth confluent on BBA. PPI-treated H. pylori showed inhibition of growth. fluorescence microscopic results showed green curved bacilli in control sample. Pure PPI stained showing fluorescence green spots with variable size. PPI-treated H. pylori appeared as red bacilli with embedded PPI.

Green curved bacilli in control sample represented intact cell membrane. However, PPI-treated H. pylori observation as red cells showed cell membrane damaging. Green fluorescent spots on the surface of red cells indicated interaction of PPIs with components of bacterial cell envelope. PPIs interaction with cell membrane may be cluster of lipid components, lead to pores formation and leakage. Bacterial growth inhibition could due to cell membrane damages.