A combination of different probiotics strains reduces the ability of potentially pathogenic bacteria to colonise the gut more than single strains, says new research that proposes industry should look to expand research in this area.
The research, published in Food Research International, reports the effects of commercial probiotic strains of reducing the adhesion and colonisation of pathogenic bacteria that could promote poor gut health.
"These results suggest that combinations of probiotics strains could be useful and more effective in inhibition of pathogen adhesion," wrote lead author Carmen Collado from the Functional Foods Forum, University of Turku.
"The inhibition and displacement profiles were very different suggesting that different mechanisms are implied in both processes."
Probiotic products containing 'friendly' bacteria are now well accepted by consumers in many European countries, with putative benefits highlighted for gut and immune health.
The benefits for gut health have been reported to be due to the probiotic bacteria adhering to the walls of the intestine, which inhibits the ability of pathogenic bacteria to stick and colonise the gut, thereby reducing the infection.
The researchers, including collaborators from Abo Akademi University in Finland, evaluated the ability of four commercial probiotic strains (Lactobacillus rhamnosus GG, L. rhamnosus LC705, B. breve 99 and Propionibacterium freudenreichii ssp. shermanii JS) either alone or in various combinations to inhibit, displace and compete with selected pathogens (Bacteroides vulgatus DSM 1447, Clostidium histolyticum DSM 627, Clostridium difficile DSM 1296, Escherichia coli K2, Listeria monocytogenes ATCC 15313, Salmonella enterica serovar Typhimurium ATCC 12028, Staphylococcus aureus DSM 20231). Valio provided all probiotics.
Collado reports that all the different probiotic combinations tested inhibited pathogenic infection by over 40 per cent for some pathogens tested, and proposed that they could be "excellent candidates" for their use as new combinations in fermented dairy products.
"The results show a very high specificity in the inhibition of the adhesion and displacement of enteropathogens by different probiotic strain combinations, indicating the need of a case-by-case characterization of these combinations," said the researchers.
"However, it must be taken into account that in vivo studies are necessary to confirm the potential effects prior to introducing such combinations to clinical intervention studies," they concluded.
Source: Food Research International
June 2007, Volume 40, Issue 5, Pages 629-636
"In vitro analysis of probiotic strain combinations to inhibit pathogen adhesion to human intestinal mucus"
Authors: M.C. Collado, J. Meriluoto, S. Selaminen