Design of a multispecies probiotic mixture to prevent infectious complications in critically ill patients

Background & aims: Although the potential for probiotics is investigated in an increasing variety of diseases, there is little or no consensus regarding the desired probiotic properties for a particular disease in question, nor about the final design of the probiotic. Specific strain selection procedures were undertaken to design a disease-specific multispecies probiotic. Methods: From a strain collection of 69 different lactic acid bacteria a primary selection was made of 14 strains belonging to different species showing superior survival in a simulated gastrointestinal environment. Functional tests like antimicrobial activity against a range of clinical isolates and cytokine inducing capacity in cultured human peripheral blood mononuclear cells were used to further identify potential strains. Results: Specific strains inhibited growth of clinical isolates whereas others superiorly induced the anti-inflammatory cytokine IL-10. Based on functional tests and general criteria regarding probiotic design and safety, a selection of the following six strains was made (Ecologic 641); Bifidobacterium bifidum, Bifidobacterium infantis, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus salivarius and Lactococcus lactis. Combination of these strains resulted in a wider antimicrobial spectrum, superior induction of IL-10 and silencing of pro-inflammatory cytokines as compared to the individual components. Conclusions: Application of strict criteria during the design of a disease-specific probiotic prior to implementation in clinical trials may provide a rational basis for use of probiotics. (C) 2007 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.