Since their first development, there has been interest in using probiotics against gut infections, particularly diarrhoeal illness. Cochrane reviews in 2010 concluded that, used alongside rehydration therapy, probiotics are safe and have clear benefits in shortening duration and reducing stool frequency in acute infectious diarrhoea (Allen et al. 2010, Bernaola Aponte et al. 2010).
Research with L. casei Shirota has investigated diarrhoea of undetermined aetiology, as well as infection with a range of pathogens, either bacterial (Clostridium difficile (Lewis et al. 2009, Martinez et al. 2003, Pirker et al. 2012), Helicobacter Pylori (Cats et al. 2003, Sgouras et al. 2004)) or viral (rotavirus (Jacalne et al. 1990), norovirus (Nagata et al. 2011)). Subjects in trials have included children, adults and older patients in hospitals or care homes. Supporting evidence also comes from extensive mechanistic and model studies.
Enteric infections affect many infants and young children, particularly in developing countries but even in the European countries. Almost all infants suffer at least one episode of rotavirus before they are five (Centers for Disease Control & Prevention 2008). Many studies have shown probiotic benefit in this area, either for reducing the duration of diarrhoea or risk of illness. The following study investigates whether diarrhoeal risk could be reduced with an intervention using L. casei Shirota.
Study: Acute diarrhoea
Method: This double-blind, placebo-controlled, randomised study involved 3,758 children aged one to five years, living in an urban slum in India. Every day for 12 weeks, the children drank a probiotic fermented milk drink (L. casei Shirota, minimum 6.5 x 109 CFU) or a placebo drink. The effects of these interventions were assessed during the drinking period and for a further 12 weeks.
Results: After 24 weeks, the incidence of diarrhoea in the probiotic group was 608 (i.e. 0.88 cases/child per year) compared to 674 for the placebo group (1.029 cases/child per year). This was equivalent to a reduction of risk of diarrhoea associated with probiotic of 14% (95% CI 4-23; P < 0.01 in adjusted model). Microbial analysis found a range of faecal pathogens, making it difficult for probiotic effect to be attributed to any particular aetiology.