Suppressive effect of frequent ingestion of Lactobacillus johnsonii La1 on Helicobacter pylori colonization in asymptomatic volunteers

Sir, Helicobacter pylori colonization occurs earlier and with a higher frequency in individuals from developing countries who live in conditions of inadequate sanitation than in indi- viduals from industrialized countries. In Chile, for example, between 60% and 70% of the adolescents and >80% of the adults from the low socio-economic stratum are colonized by this pathogen.1 This high prevalence may have important consequences as H. pylori is currently recognized as an aetio- logical factor of gastroduodenal ulcer and as a risk factor for the development of gastric adenocarcinoma, a highly preva- lent cancer in Chile. In most people, however, the presence of H. pylori in the gastric mucosa remains asymptomatic during life, and in consequence it is neither possible nor ethical to eradicate the bacteria colonizing their gastric mucosa with antibiotics. Furthermore, treatment with antibiotics presents other problems related to its high cost for families from the low socio-economic stratum and to the appearance of resist- ance in H. pylori as well as in other species. For these reasons, it is important to develop low-cost, large-scale alternative solutions applicable to the at-risk population to prevent or decrease H. pylori colonization. In this sense, the use of dietary components capable of interfering with H. pylori, including some vegetables and probiotic microorganisms, appears attractive.2 Some specific strains of exogenous lactobacilli are resist- ant to the low pH of the stomach and may transiently adhere to the gastric mucosa, where they may exert functional effects. Some of them have been shown to exert in vitro and in vivo bactericidal effects against H. pylori, suggesting that they could possibly interfere with H. pylori colonization