In vitro evaluation of the mucin-adhesion ability and probiotic potential of Lactobacillus mucosae LM1

Aims: In this report, we characterized the probiotic potential of Lactobacillus mucosae LM1, focusing on its in vitro mucin-adhesion abilities. Methods and Results: Screening assays were used to evaluate LM1. Previous studies on Lact. mucosae species have been performed, but few have examined the ability of this species to adhere to and colonize the intestinal mucosa. Thus, adhesion, aggregation and pathogen inhibition assays of LM1 along with microbial adhesion to solvents (MATS) assay were carried out in comparison with another putative probiotic, Lactobacillus johnsonii PF01, and the commercial strain, Lactobacillus rhamnosus GG. Based on MATS assay, the cell surfaces of the lactobacilli strains were found to be hydrophobic and highly electron-donating, but the average hydropathy (GRAVY) index of predicted surface-exposed proteins in the LM1 genome indicated that most were hydrophilic. LM1 showed the highest adhesion, aggregation and hydrophobicity among the strains tested and significantly inhibited the adhesion of Escherichia coli K88 and Salmonella enterica serovar Typhimurium KCCM 40253. Correlations among adhesion, aggregation and hydrophobicity, as well as between coaggregation and displacement of E. coli, were observed. Conclusions: Increased adhesion may not always correlate with increased pathogen inhibition due to various strain-specific mechanisms. Nevertheless, LM1 has promising probiotic properties that can be explored further using a genomics approach. Significance and Impact of the Study: Our data on adhesion of LM1 strain showed a significant correlation between adhesion, hydrophobicity of cell surface and autoaggregation. This study gives basic knowledge for the elucidation of the adhesion mechanism of Lactobacillus sp. and prediction of its adherence in specific host models.