Adhesion abilities of dairy Lactobacillus plantarum strains showing an aggregation phenotype

Bacterial aggregation phenotype and cell surface hydrophobicity of dairy Lactobacillus plantarum strains were screened in order to assess a correlation with their adhesion and pathogen competitive exclusion abilities. Lactobacilli strains showing an aggregation phenotype, L. plantarum IFPL33, IFPL81, IFPL150, IFPL156 and IFPL162, also exhibited the highest percentages of autoaggregation (> 50%) at 24 h. In addition, autoaggregation abilities of the lactobacilli were highly correlated with their percentages of co-aggregation with all the pathogens tested, although co-aggregation properties were pathogen specific. Nevertheless, none of the autoaggregation and co-aggregation abilities correlated with the affinity to xylene (hydrophobicity) and the ability of adhesion to Caco-2 cells. Furthermore, these properties are not fully correlated with the ability of the lactobacilli strains for inhibiting pathogen adhesion. Aggregation abilities and cell surface hydrophobicity may not be the only components responsible for adhesion but some of the criteria to bear in mind of a complex mechanism that enables microorganisms to interact with the host and exert its beneficial effect. Further research is needed to identify remaining attributes related to adhesion and pathogen exclusion properties of potential probiotic strains.