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Ferreira C.L.,Federal University of Viçosa | Ferreira C.L.,University of Turku | Grzeskowiak L.,University of Turku | Collado M.C.,University of Turku | And 2 more authors.
Journal of Food Protection | Year: 2011

Numerous Lactobacillus species are members of the normal healthy human intestinal microbiota, and members of the Lactobacillus family predominate among the current marketed probiotic strains. Most of the current commercial probiotic strains have not been selected for specific applications but rather have been chosen based on their technological properties. Often the ability of such strains to temporarily colonize the gastrointestinal tract may be lacking, and the interactions with intestinal microbiota are few. Furthermore, the competitive exclusion properties of potential probiotic bacteria are strain specific and vary greatly. Thus, it is highly desirable that new candidate probiotic isolates originate from the healthy target population. In this study, seven newly isolated strains of Lactobacillus gasseri originating from feces of a healthy newborn child were evaluated for their ability to adhere to intestinal mucus, to autoaggregate and coaggregate with the model pathogens Cronobacter sakazakii (ATCC 29544) and Clostridium difficile (1296). All the bacterial strains, single or in combination, in viable and nonviable forms, were able to autoaggregate. The coaggregation with C. sakazakii or C. difficile was higher (P < 0.05) in nonviable than in the viable forms. Single L. gasseri strains showed similar adhesion abilities to intestinal colon mucus. The seven L. gasseri strains when combined were also able to significantly compete with, displace, and inhibit the adhesion of C. sakazakii and C. difficile in the mucus model. This study demonstrates that the studied L. gasseri strains fulfill the basic adhesion and aggregation properties for probiotics and could be considered for potential future use in children. Copyright ©, International Association for Food Protection.


Grzeskowiak L.,University of Turku | Collado M.C.,University of Turku | Collado M.C.,Institute of Agrochemistry and Food Science IATA | Vesterlund S.,University of Turku | And 2 more authors.
Aquaculture | Year: 2011

Adhesion to the host mucus represents the first crucial step in most infections caused by pathogenic bacteria. To characterize this phenomenon, the adhesion of Aeromonas hydrophila, Aeromonas salmonicida, Edwardsiella tarda and Vibrio anguillarum to mucus from different parts of three fish species was analyzed. Furthermore, the adherence of two commensal bacteria isolated from fish, Leuconostoc citreum and Enterococcus durans was assessed. To determine whether the observed bacterial adhesion to fish mucus was caused by non-specific interactions, adhesion to bovine serum albumin (BSA), gelatin and polystyrene was also tested. Our results demonstrated that non-specific adhesion such as hydrophobic interactions are only partially involved in the binding process since adhesion to BSA was low, and there was no correlation between adhesion to polystyrene and adhesion to fish mucus.These results indicate the need for a case-by-case assessment in order to select strains with the further ability to inhibit or displace specific pathogens. Specific probiotics selected for further pathogen exclusion could be useful tools to reduce and/or to prevent common fish infections. © 2011 Elsevier B.V.


Grzeskowiak L.,University of Turku | Collado M.C.,Institute of Agrochemistry and Food Science IATA | Salminen S.,University of Turku
Aquaculture | Year: 2012

Bacterial aggregation is related to cell-to-cell adherence between bacteria of the same or different strains. This phenomenon is known to have an important role in microbial interactions and in aquaculture. The aim of the present study was to evaluate the aggregation properties of bacterial candidates for fish probiotics and to assess these properties in viable and non-viable forms with fish bacterial pathogens. The microorganisms Leuconostoc citreum and Enterococcus durans in viable and non-viable forms were evaluated with fish pathogens Aeromonas hydrophila, Aeromonas salmonicida, Edwardsiella tarda and Vibrio anguillarum. L. citreum showed higher auto-aggregation properties in non-viable vs. viable form (P = 0.005). The co-aggregation percentage of viable L. citreum+. A. hydrophila differed from those of L. citreum+. E. tarda, and L. citreum+. V. anguillarum (P = 0.033, P = 0.013, respectively). The co-aggregation abilities with A. salmonicida and E. tarda were higher with non-viable than viable cells of this microorganism (P = 0.023 and P = 0.020, respectively). Non-viable form of E. durans co-aggregated at different percentage with A. hydrophila compared to A. salmonicida and to E. tarda (P = 0.023, P = 0.030, respectively).The results suggest that the ability to auto- and co-aggregate with pathogens can be a useful tool for preliminary screening in order to identify potential probiotic bacteria suitable for use in aquaculture. © 2012 Elsevier B.V.

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