Strengthening intestinal microbiota: a prophylactic treatment for traveler’s diarrhea? Some studies suggest that it is possible, but more research still needs to be done.
People who travel to countries with warm climates and poor hygienic conditions are exposed to a significant risk of infectious diarrhea: between 10% and 40% of them will be affected during their stay1. In the majority of cases, this diarrhea is due to pathogenic bacteria (Escherichia coli, Salmonella, Shigella, Campylobacter jejuni, etc.) However, parasites (Giardia lamblia, Cyclospora, Cryptosporidium, etc.) and viruses (norovirus, rotavirus, etc.) are implicated in around 10% of cases2.
Not always a minor problem
Although “turista” is common, it is not without consequences. In reality, diarrhea disrupts the equilibrium of intestinal microbiota at least temporarily, which can have long-term consequences, particularly because it increases the risk of developing irritable bowel syndrome3. In the short term, it presents a risk of impairment of drug absorption and a risk of dangerous dehydration in sensitive people.
Probiotics as a preventive treatment
Microbiota is the body’s first line of defense against enteric infections. Probiotics have long been envisioned as a way to prevent traveler’s diarrhea. For example, an Austrian team conducted two randomized, controlled studies almost thirty years ago on the effects of the probiotic yeast Saccharomyces boulardii.
Proven effectiveness in clinical studies
Several studies have shown that preventive treatment with the probiotic yeast Saccharomyces boulardii can reduce the risk of developing diarrhea.4,5 Some randomized, controlled trials have also suggested the preventive potential of combining lactobacilli with other families of bacteria.6 However, well-conducted studies with prebiotics or probiotics still remain few as of today1.
1- Steffen R et al. Traveler’s diarrhea: a clinical review. JAMA 2015 ; 313 : 71-80. https://www.ncbi.nlm.nih.gov/pubmed/?term=Steffen+R%2C+Hill+DR%2C+DuPont+HL.+Traveler%E2%80%99s+diarrhea%3A+a+clinical+review.+JAMA+2015+%3B+313+%3A+71-80.
2- CHU Rouen. La diarrhée du voyageur [en ligne]. Extrait et inspiré de « Vacinnation : visa pour... la diarrhée du voyageur. Aspects actuels et perspectives ». Dr Patrice Bourée – N°8/1997. Mis à jour le 13 août 1998 par Jean Philippe Leroy. [consulté le 30/01/2017]. Disponible à l'adresse : http://www.chu-rouen.fr/cap/tourista.html
3- Schwille-Kiuntke J et al. Systematic review and meta-analysis: post-infectious irritable bowel syndrome after traveller’s diarrhoea. Aliment Pharmacol Ther 2015 ; 41 : 1029-37. https://www.ncbi.nlm.nih.gov/pubmed/25871571
4- Kollaritsch H et al. Prevention of traveller’s diarrhea : comparaison of different non antibiotic preparations. Travel Med Int 1989 : 9-17. https://www.optibacprobiotics.co.uk/uploads/kollaritsch,_h._et_al_(1993)_prevention_of_traveller's_diarrhoea_for_travelling_abroad_optibac_probiotics_www.optibacprobiotics.co.uk.pdf
5- Kollaritsch H et al. [Prevention of traveler’s diarrhea with Saccharomyces boulardii. Results of a placebo controlled double-blind study]. Fortschr Med 1993 ; 111 : 152-6. https://www.ncbi.nlm.nih.gov/pubmed/8486328
6- McFarland LV. Meta-analysis of probiotics for the prevention of traveler’s diarrhea. Travel Med Infect Dis. 2007;5(2):97-105. https://www.ncbi.nlm.nih.gov/pubmed/?term=McFarland+LV.+Meta-analysis+of+probiotics+for+the+prevention+of+traveler%E2%80%99s+diarrhea.+Travel+Med+Infect+Dis.+2007%3B5(2)%3A97-105.