Direct evidence by DNA fingerprinting that endoscopic cross-infection of Helicobacter pylori is a cause of postendoscopic acute gastritis

The DNA fingerprinting of Helicobacter pylori strains in two cases of acute gastritis that occurred after endoscopy was examined. H. pylori was isolat ed from the stomachs of two patients with acute gastritis and from the stom achs of the patients in whom the same gastrofiberscope had previously been used. The genomic DNA digested with HaeIII was subjected to pulsed-field ge l electrophoresis. The corresponding paired electrophoretic patterns were c ompletely identical. These findings provide direct evidence that postendosc opic acute gastritis can be caused by cross-infection with H. pylori via en doscopy.