Proton Pump Inhibitor-Treated H. pylori Adjust Cell Envelope Fatty Acid and Cholesterol Content to Survive

Proton pump inhibitors (PPIs) with lipophilic nature may interact with lipid components of H. pylori cell membrane, disrupting cell structure and viability. In this study, the effect of PPIs on fatty acid and cholesterol components of H. pylori cell membrane was assessed.

One H. pylori isolate was treated with 1X and 2X MICs (μg/mL) of lansoprazole (LPZ: 8 and 16) and pantoprazole (PAN: 128 and 256) in brain heart infusion broth plus serum. Treated H. pylori was cultured on brucella blood agar (BBA) and tetrazolium egg yolk agar (TEYA). Bacterial cells stained with Live/Dead kit were examined by fluorescent microscopy. Fatty acid and cholesterol contents of treated H. pylori were measured by gas chromatography.

PPI-treated H. pylori did not grow on BBA but grew on TEYA. Fluorescent microscopy showed H. pylori stained red. Analyses showed high frequency of saturated fatty acids, C14:0, C16:0 and C18:0. Among unsaturated fatty acids, C18:1 and C18:2c were increased, while five were eliminated and five were synthesized de novo. Cholesteryl-6-O-tetradecanoyl-α-D- glucopyranoside was detected as the only glycosylated cholesterol in treated H. pylori. Growth of PPI-treated H. pylori on cholesterol-rich TEYA showed that occurrence of cholesterol can reverse the growth inhibition by PPIs. Red- bacilli form of H. pylori showed dye entry through damaged cell membrane without lysis.

Incorporation of lipophilic PPI into H. pylori cell membrane disrupted lipids and inhibited growth. However, H. pylori adjusted the defected membrane by replacing the lipid components and resisted lysis.