Acid-tolerance response in Helicobacter pylori and differences between cagA+ and cagA- strains

J Infect Dis. 1998 Jul;178(1):213-9. doi: 10.1086/515606.


Helicobacter pylori cagA transcription and translation are maximal at pH 6 in stationary phase. The aim of this study was to determine whether H. pylori has an acid-tolerance response and whether that response is related to CagA expression, by investigating whether preexposure to pH 5 or 6 improved survival of cells subsequently exposed to pH 3. Cell number was determined after broth growth, after exposure to pH 5, 6, or 7, and then after a 30-min exposure to pH 3 without urea. H. pylori cells preexposed to pH 6 or 5 survived pH 3 exposure 100-fold better than did cells preexposed to pH 7. Cells of cagA+ strains grown at pH 6 for 48 h, which induced maximal CagA expression, were significantly more susceptible to pH 3 than were wild type cagA- strains or isogenic cagA- knockouts. Thus, H. pylori strains possess a urea-independent acid-tolerance response. Differential acid susceptibility may contribute to preferential colonization of particular H. pylori strains in specific mucus layer niches.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigens, Bacterial*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology*
  • Colony Count, Microbial
  • Helicobacter pylori / genetics
  • Helicobacter pylori / growth & development*
  • Humans
  • Hydrogen-Ion Concentration


  • Antigens, Bacterial
  • Bacterial Proteins
  • cagA protein, Helicobacter pylori