Species- and Age/Generation-Dependent Adherence of Bifidobacterium bifidum to Human Intestinal Mucus In Vitro

Adhesion to intestinal mucus is the first event in the process by which intestinal microbes colonize the intestine. It plays a critical role in the initiation of interactions between gut microbes and host animals. Despite the importance, the adhesion properties of probiotics are generally characterized using porcine mucin; adhesion to human mucus has been poorly characterized. In the present study, human intestinal mucus samples were isolated from 114 fecal samples collected from healthy infants and adults. In initial screening, four out of the 13 beneficial microbes tested, including the type strain of Bifidobacterium bifidum, B. bifidum TMC3115, Lacticaseibacillus rhamnosus GG, and Bifidobacterium animalis subsp. lactis Bb12, showed strong adhesion abilities to human mucus. The type strain of B. bifidum and TMC3115 adhered more strongly to neonatal and infant mucus than to adult mucus, while L. rhamnosus GG and B. lactis Bb12 adhered more strongly to adult mucus than to infant mucus. Similar results were obtained for ten additional strains of B. bifidum. In conclusion, age/generation-related differences were observed in the adhesion properties of B. bifidum and other strains. A deeper symbiotic relationship may exist between infants, particularly neonates, and B. bifidum based on its enhanced adhesion to neonatal intestinal mucus.