Background: Proton pump inhibitor-based therapy including two antibiotics i
s the treatment of choice for Helicobacter pylori infection. Oral antibioti
c treatment can lead to intestinal overgrowth of potentially pathogenic bac
Aim: To investigate the intestinal microflora before and at different times
after H. pylori treatment with omeprazole, clarithromycin and metronidazol
Methods: Bacterial growth in faecal samples from 51 patients infected with
H. pylori was determined qualitatively and quantitatively. During the same
period of time, stool samples from 27 H. pylori-negative controls were take
n and investigated at the same intervals.
Results: The microflora of H. pylori-infected patients was different from t
hat in H. pylori negative controls. It was characterized by a high concentr
ation of lactobacilli, mainly Lactobacillus acidophilus. Immediately after
therapy there was an increased colonization with yeasts, while the growth o
f lactobacilli and other species was inhibited. Clostridium difficile was c
ultured from three cases, but without clinical manifestations of pseudomemb
ranous colitis. After 4 weeks of therapy, the microflora returned to normal
and was not different from that of the H. pylori-negative control group.
Conclusions: In H. pylori-positive patients the intestinal flora is charact
erized by an increase in growth of acid-tolerant L. acidophilus. Eradicatio
n therapy exerts only a short-term influence on intestinal flora, whereas i
n the long term, the intestinal microflora is restored to a pattern similar
to that of the control group.