ACETALDEHYDE AND ETHANOL-PRODUCTION BY HELICOBACTER-PYLORI

By virtue of possessing alcohol dehydrogenase activity, cytosol prepar ed from Helicobacter pylori produces toxic acetaldehyde from ethanol i n vitro. To approach the in vivo situation in the stomach, we have now investigated whether intact H. pylori-without addition of exogenous n icotinamide adenine dinucleotide-also forms acetaldehyde. Furthermore, to assess the energy metabolism of H. pylori, we determined whether t he alcohol dehydrogenase-catalyzed reaction can run in the opposite di rection with ethanol as the end-product and thereby yield energy for t he organism. Intact H. pylori formed acetaldehyde already at low ethan ol concentrations (at 0.5% ethanol, acetaldehyde, 64 +/- 21 and 75 +/- 9 mu mol/l (mean +/- SEM) for strains NCTC 11637 and NCTC 11638, resp ectively). H. pylori produced ethanol in concentrations that can be si gnificant for the energy metabolism of the organism. Acetaldehyde prod uction by H, pylori may be an important factor in the pathogenesis of gastroduodenal diseases associated with the organism. The primary func tion of H, pylori alcohol dehydrogenase may, however, be alcoholic fer mentation and consequent energy production under microaerobic conditio ns.