Comparison of in vitro models to study bacterial adhesion to the intestinal epithelium

Abstract

[Aims]: To evaluate the adhesion ability of intestinal bacteria to different in vitro models of intestinal epithelia, and to estimate the suitability of these models and the type of interactions involved.

[Methods and results]: The adhesion of probiotic (Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis Bb12), commensal (B. animalis IATA-A2 and B. bifidum IATA-ES2) and potentially pathogenic bacteria (E. coli and L. monocytogenes) was determined. The adhesion models used were polycarbonate-well plates, with or without mucin, and different configurations of Caco-2 and/or HT29-MTX cell cultures. All bacteria adhered to wells without mucin (2·6–27·3%), the values being highly variable depending on the bacterial strain. Adhesion percentages of potentially probiotic bacteria to Caco-2 cultures were remarkably lower (P < 0·05) than those to mucin, and more similar to those of pathogenic strains. The lowest adhesion of different bacterial strains was detected on HT29-MTX (0·5–2·3%) cultures and Caco-2/HT29-MTX (0·6–3·2%) cocultures, while these values were increased in Caco-2 cultures plus mucin.

[Conclusions]: The results suggested that bacterial strains exhibit different capacities to adhere to cellular components and several types of mucin present in different models, showing preferences for intestinal MUC2.

[Significance and impact of the study]: The use of Caco-2 cells monolayer plus mucin (type II) better approaches the physiological characteristics of in vivo situation, providing a reliable and suitable in vitro model to evaluate bacterial adhesion.