Effect of Helicobacter pylori Infection on Symptoms of Gastroenteritis Due to Enteropathogenic Escherichia coli in Adults

Abstract

Helicobacter pylori can cause hypochlorhydria in some hosts and predispose to diarrheal infections. We tested the hypothesis that chronic H. pylori infection increases the risk of diarrheal illness due to an acid-sensitive organism: enteropathogenic Escherichia coli (EPEC). After testing healthy adult volunteers for H. pylori, 19 infected and 26 uninfected subjects had gastric pH probes placed and were given 5-10 × 10(9) EPEC organisms; six had previously received a proton pump inhibitor. We measured diarrhea and created a composite gastroenteritis severity score based on symptoms in the 48 h following exposure. Outcomes were compared using logistic regression and analysis of covariance. More H. pylori-infected (36.8%) than H. pylori-uninfected subjects (7.7%) were hypochlorhydric (P = 0.02). Six (31.6%) H. pylori-infected and five H. pylori-uninfected subjects (19.2%) developed diarrhea (P = 0.34). Hypochlorhydria was a strong risk factor for diarrhea [odds ratio (OR) 6.25, confidence interval (CI): 1.29-30.35]. After adjusting for hypochlorhydria and EPEC dose, H. pylori was not associated with diarrhea (OR 0.89, CI: 0.17-4.58). Among those with symptoms, H. pylori-infected subjects had lower gastroenteritis severity score than did H. pylori-uninfected subjects (2.6, CI: 1.9-3.4 versus 1.5, CI: 1.1-1.9, P = 0.01), particularly if they were also hypochlorhydric (3.8, CI: 2.3-5.3 versus 1.9, CI: 1.3-2.5, P = 0.02). In adults, H. pylori infection was associated with hypochlorhydria but had no detectable effect on occurrence of diarrhea. Among symptomatic subjects, H. pylori infection decreased severity of gastroenteritis.