The proton pump inhibitor omeprazole inhibits acid survival of Helicobacter pylori by a urease-independent mechanism

TY - JOUR

T1 - The proton pump inhibitor omeprazole inhibits acid survival of Helicobacter pylori by a urease-independent mechanism

AU - McGowan, Catherine C.

AU - Cover, Timothy L.

AU - Blaser, Martin J.

PY - 1994/11

Y1 - 1994/11

N2 - Background/Aims: Omeprazole, a benzimidazole proton pump inhibitor, has an antibacterial effect against Helicobacter pylori at neutral pH and inhibits its urease activity. The aim of this study was to characterize H. pylori acid resistance and to determine whether omeprazole affects its survival at low pH. Methods: We studied survival of H. pylori and other enteric organisms in buffered solutions (pH 2-7) in the presence or absence of 10 mmol/L urea and/or Omeprazole. Results: In the absence of urea, the acid tolerances of wild-type H. pylori, a urease-negative H. pylori mutant, Escherichia coll, and Proteus mirabilis were similar. In the presence of urea, the survival of the wild-type H. pylori at pH 2 was significantly greater than that of the other organisms. Omeprazole (100 μ/mL) had a marked inhibitory effect on the survival of both wild-type and urease-negative H. pylori at low pH, and similar effects on E. coli, P. mirabilis, and Salmonella typhimurium. Conclusions: Whereas survival of H. pylori below pH 4 is urease dependent, H. pylori uses non-urease-mediated mechanisms at or above pH 4. Omeprazole inhibits the survival of H. pylori at low pH through a mechanism independent of its effect on urease, an antibacterial effect that extends to other enteric bacteria.

AB - Background/Aims: Omeprazole, a benzimidazole proton pump inhibitor, has an antibacterial effect against Helicobacter pylori at neutral pH and inhibits its urease activity. The aim of this study was to characterize H. pylori acid resistance and to determine whether omeprazole affects its survival at low pH. Methods: We studied survival of H. pylori and other enteric organisms in buffered solutions (pH 2-7) in the presence or absence of 10 mmol/L urea and/or Omeprazole. Results: In the absence of urea, the acid tolerances of wild-type H. pylori, a urease-negative H. pylori mutant, Escherichia coll, and Proteus mirabilis were similar. In the presence of urea, the survival of the wild-type H. pylori at pH 2 was significantly greater than that of the other organisms. Omeprazole (100 μ/mL) had a marked inhibitory effect on the survival of both wild-type and urease-negative H. pylori at low pH, and similar effects on E. coli, P. mirabilis, and Salmonella typhimurium. Conclusions: Whereas survival of H. pylori below pH 4 is urease dependent, H. pylori uses non-urease-mediated mechanisms at or above pH 4. Omeprazole inhibits the survival of H. pylori at low pH through a mechanism independent of its effect on urease, an antibacterial effect that extends to other enteric bacteria.

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U2 - https://doi.org/10.1016/0016-5085(94)90582-7

DO - https://doi.org/10.1016/0016-5085(94)90582-7

M3 - Article

C2 - 7926527

VL - 107

SP - 1573

EP - 1578

JO - Gastroenterology

JF - Gastroenterology

SN - 0016-5085

IS - 5

ER -