Beneficial lactobacilli for improving respiratory defenses: the case of Lactobacillus rhamnosus CRL1505

Abstract

Lactic acid bacteria (LAB) are technologically and commercially important and have various beneficial effects on human health. Several studies have demonstrated that certain LAB strains can exert their beneficial effect on the host through their immunomodulatory activity. Although most research concerning LAB-mediated enhanced immune protection is focused on gastrointestinal tract pathogens, recent studies have centred on whether these immunobiotics might sufficiently stimulate the common mucosal immune system to provide protection to other mucosal sites as well. In this sense, LAB have been used for the development of probiotic foods with the ability to stimulate respiratory immunity, which would increase resistance to infections, even in immunocompromised hosts. This article examines the current scientific literature dealing with the use of probiotic strains to prevent respiratory infections. More specifically, the present work reviews the work of our laboratory in the use of Lactobacillus rhamnosus CRL1505 for the improvement of respiratory immunity in adult immunocompetent host and the early recovery of the immune mechanisms against respiratory pathogens in malnourished hosts. Moreover, considering that recent reviews suggest common respiratory infectious diseases continue to be a major cause of death among preschool children in developing countries and that the identification of feasible strategies to combat this disease burden is an important public health need, we have evaluated the efficacy of L. rhamnosus CRL1505 in preventing respiratory infections and severe illnesses, in children aged 2–6 years. The research from our laboratory demonstrates that L. rhamnosus CRL1505 represent a promising resource for the development of prevention strategies against respiratory infections that could be effective tools for medical application.