Human alimentary tract harbors hundreds of commensal microbes that interact with the host and provide genetic, metabolic, and immunological attributes [29]. On the other hand, infection with dysbiotic microbes or environmental stresses such as exposure to xenobiotics could alter compositional or functional properties of gut microbes and disrupt immune homeostasis by specific members of this community [30,31]Since K. dentrificans could be colonized into atrophic gastric epithelium where the mucosal barrier systems are perturbed due to chronic inflammation, it might profoundly affect pathology and clinical prognosis of chronic gastritis caused by H. pylori infection. Moreover, the commensal may interact with H. pylori to stimulate inflammatory signals that have a great impact on the tumor development and progression [32]. Consistent with this idea, the commensal microbes switch their contribution from gastrointestinal homeostasis to pathogenic inflammation, once they communicate with dysbiotic pathogens such as Salmonella typhimurium [33]. Furthermore, it is of great interest to evaluate whether infections with K. dentrificans or other commensals are associated with the susceptibility to gastric inflammation and tumorigenicity in patients with H. pylori infection. Conclusively, a careful administration of anti-acids to the elderly, especially those with atrophic gastritis, is required to maintain the gastric barrier to other bacteria.