Control of Helicobacter Pylori Infection by Probiotics

Helicobacter pylori colonises an estimated 50% of the world´s population (Taylor \& Blaser, 1991; Go, 2002). Despite clear clinical guidelines on the treatment of this infection (Malfertheiner et al. 2007) there is a drive to find alternative ways to control this infection in a wider perspective without the complications of induction of antibiotic resistance in the pathogen. L. reuteri has been widely studied in clinical trials and has been shown to have probiotic, health-promoting effects in both adults and children (Connolly 2004; Casas \& Dobrogosz, 2000). L. reuteri has been shown in numerous studies to be safe for human consumption and it has been shown to colonise the human gastrointestinal tract (Wolf et al., 1995, Valeur et al., 2004). Studies using supplementation with L. reuteri in both symptomatic and non-symptomatic H. pylori-infected subjects show a clear reduction of infection load after 4 weeks of use and this was concomitant with a reduction in symptoms associated with the infection (Imase et al. 2007; Francavilla et al. 2007, unpublished data). Further, dietary supplementation with L. reuteri during and after the period of H. pylori eradication therapy has also been shown to reduce the side effects of this therapy without affecting the degree of eradication (Lionetti et al., 2007). It is also feasible, through the inhibitory action of L. reuteri on H. pylori, that pre-exposure to L. reuteri may weaken H. pylori and make it more susceptible to antibiotic attack during eradication. However, an earlier pilot study was not been able to demonstrate a reduction in gastric inflammation caused by H. pylori. This pilot study was performed with L. reuteri ATCC 55730 that has since been found to lack anti-inflammatory activity in in vitro screens. Recent selection of natural, human L. reuteri strains has identified a specific strain with strong anti-inflammatory properties in vitro (Lin et al, 2007 and submitted 2007). A combination of this strain, together with the earlier proven L. reuteri strain, is expected to lead to both a reduction of H. pylori load as well as a reduction in the gastric inflammation related to the pathogen.