Surface characterization and adhesive properties of bifidobacteria

BIBILONI R; PÉREZ P; GARROTE G L; DI SALVO A; DE ANTONI G

Microbial growth in biofilms, Part A. Developmental and Molecular Biological Aspects. Methods in Enzimology. Vol 336

Academic Press

Año: 2001; p. 411 - 427

It is generally recognized the importance of the intestinal microflora in the health status. The colonization of the tract by beneficial microorganisms constitutes the first defensive barrier against the invasion of pathogenic microorganisms or toxic substances. The ability to adhere to the intestinal epithelia and to compete with other microorganisms seems to be crucial for a probiotic strain to colonize the gastrointestinal tract. Bifidobactera are normal inhabitants of the gut of humans and animals where they play and important role in the prevention of gastrointestinal disorders. The protection of the intestinal epithelia could be ascribed to the adherent properties of some strains and to the liberation of antimicrobial substances. One approach to obtain information regarding the adherent behavior in the intestinal ecosystem, is to study the surface properties of the selected strains. The adherence of microorganisms to natural environments can be inferred studying the surface properties of bacteria employing a combination of methodologies.This procedure includes several determinations such as partitioning of bacteria in hydrocarbon-aqueous interfaces, zeta potential, binding to solid surfaces, capacity to aggregate particles and adherence to monolayers of cell cultures. We applied these methodologies to a collection of bifidobacteria isolated at CIDCA and to reference strains. This procedure allowed to select adherent strains on the basis of their capacity to bind to different surfaces and to correlate these properties with the nature of the bacterial surface. When designing a strategy to study the bacterial surface, the methods should be carefully standardized. It is important to report the resuspending buffers since ionic strength and pH may have an effect on the results obtained. Temperature of assays as well as the conditions in which the bacteria were grown are also important. Should comparisons between laboratories are to be done, it is recommended to include reference strains with different adherent properties.