In vitro adhesion of propionic acid bacteria to human intestinal mucus

Abstract

Propionic acid bacteria (PAB) have widely been used as starter cultures. Their potential as probiotics has, however, received little attention. Adhesion to the intestinal mucosa is considered one of the main selection criteria for probiotic micro-organisms. Therefore, in the current study the adhesion of PAB to human intestinal mucus was investigated in an in vitro model. The tested PAB exhibited a low to moderate level of adhesion (0.4 to 4.5% of the applied bacteria). Because adhesion to mucus and bovine serum albumin were similar, it is likely that the adhesion to mucus is the result of non-specific interactions. The adhesion to mucus could be significantly enhanced by prior adhesion of existing probiotic strains. The PAB did not affect the adhesion of these probiotics. Adhesion of the moderately adhering strains was found to be close to maximum within 30 s showing that the adhesion happens almost instantaneously, while the adhesion of the low binding strains increased until 1 h of incubation. These results together with earlier observations on the properties of PAB indicate that selected PAB have good prerequisites for probiotic use.