However, colonization of urease-negative H. pylori and Campylobacter jejuni is reported in patients receiving acid-reducing compounds [7,8]. Moreover,predisposed decrease of acid secretion, due to therapy, disease,or age, increased bacterial population in gastric juice [9,10].Disproportional use of proton pump inhibitors is considered to promote small intestinal bacterial overgrowth, which is prevalent in patients with irritable bowel disease (IBD) [11]. Thegastrointestinal microbiota clearly contributes to development of IBD both in mouse models and patients [12].