INFLUENCE OF OMEPRAZOLE ON UREASE ACTIVITY OF HELICOBACTER-PYLORI IN-VITRO

The influence of omeprazole on urease activity of 13 Helicobacter pylo ri strains was assessed in vitro employing different inocula of the ba cteria and various concentrations of omeprazole. Bacteria were grown i n liquid culture supplemented with omeprazole for 48 h. Afterwards, ba cterial numbers were assessed and urease activity was measured in a sp ectrophotometric assay. In 10 strains, omeprazole had no influence on urease activity at concentrations up to 8 mg/l; higher concentrations had a bacteriostatic effect. Three strains were more resistant to omep razole: These showed a marked diminution of urease activity although b acterial numbers were only slightly reduced. Thus a possible inhibitor y effect of omeprazole should be taken into account when urease of Hel icobacter pylori is measured for diagnostic purposes.