We hypothesize that the S. salivarius strain from the stomach of a Colombian patient elicited a stronger Th1- and Th17-mediated immune response, allowing the overexpression of proinflammatory cytokine genes Il-1β, Il-17A, and Ifn-γ, which promoted chronic gastric inflammation and more severe gastric hyperplasia and dysplasia in H. pylori-infected INS-GAS mice cocolonized with S. salivarius. The gene discussed is IL17A; the disease is dysplasia.