Helicobacter pylori may survive ampicillin treatment in the remnant stomach.

Helicobacter pylori (H. pylori) is a Gram-negative curved rod-like or spiral bacterium that chronically infects the human gastric mucosa, and is a major risk factor for gastritis, gastric and duodenal ulcer and adenocarcinoma of the stomach. After partial gastrectomy, some patients may have persistent H. pylori infection for five years or more. In this study, we detected three bacteria, i.e., Klebsiella pneumoniae, Enterobacter aerogenes, and Escherichia coli, in the gastric juice of patients with a remnant stomach. Some of these bacteria produced beta-lactamase. These findings are potentially important since such bacteria could provide H. pylori with the chance to acquire drug resistance and to transfer drug resistance genes. This could be one reason why H. pylori is difficult to eradicate in the remnant stomach.