Mp. Williams et al., The effect of omeprazole dosing on the isolation of Helicobacter pylori from gastric aspirates, ALIM PHARM, 13(9), 1999, pp. 1161-1169
Background: Animal experiments suggest that omeprazole dosing increases she
dding of Helicobacter into the gastric lumen, and hence into gastric juice.
Aim: To assess the effect of omeprazole dosing on the yield of H. pylori fr
om gastric aspirates of infected volunteers,
Methods: Six serial nasogastric aspirates, three before and three during do
sing with omeprazole 40 mg b.d., were obtained for culture from 10 H, pylor
i infected volunteers and one uninfected volunteer. To reduce contamination
, samples were diluted 1:10 with Maximum Recovery Diluent (MRD: pH 7.0) or
HCl-KCl buffer (pH 2.2) prior to culture on Columbia and Dent's agar,
Results: Undiluted gastric juice cultures were rapidly overgrown by upper r
espiratory tract flora, HCl-KCl dilution resulted in isolation of H, pylori
from 77% of infected subject aspirates before, and 67% of aspirates during
dosing with omeprazole, The yields were significantly lower with MRD dilut
ion, 47% and 10%, respectively, Omeprazole dosing significantly decreased t
he yield after MRD dilution, but not after HCl-KCl dilution.
Conclusions: Decreasing intragastric acidity, by dosing with omeprazole, de
creases the isolation of H. pylori from routinely processed gastric aspirat
es. In vitro acidification of gastric aspirates, by HCl-KCl dilution, incre
ases the isolation of H. pylori both before and during omeprazole dosing.