Absence of host specificity for in vitro adhesion of probiotic lactic acid bacteria to intestinal mucus

Adhesion of probiotic lactic acid bacteria (LAB) has been reported to be host species specific. Host specificity is regarded as a desirable property for probiotic bacteria and therefore recommended as one of the selection criteria. However, previous studies have indicated that LAB originating from one host adhere well also to the mucus of other species. The aim of the study was to investigate the host specificity of LAB adhesion in human, canine, possum, bird and fish mucus in vitro. An in vitro mucus adhesion model was utilized in this study using immobilized mucus from faeces or intestinal material of these hosts. The results indicate that the adhesion trait was not host specific but rather was characteristic to LAB species. In conclusion, mucus adhesion properties are more dependent on the LAB strain than on the host. This suggests that animal models in probiotic adhesion assays may be more applicable to other species than thought earlier. Positive health effects facilitated by adherent probiotics in humans may also denote the possibility of similar outcome in other species and vice versa.