Adherence Capability to Different Cultured Cell Lines of Streptococcus sp. Strains Isolated from Pozol a Prehispanic Mexican Fermented Beverage

Abstract

Pozol is an acid fermented pre-hispanic beverage, consumed as part of the diet of ethnic groups in Southern and Southeastern Mexico. Streptococcus sp. a major component of pozol microbiota, was analyzed to assess their in vitro adherence ability to HEp-2, HeLa, HT-29 and Caco-2 cell lines. Adhesion tests were performed in 35 strains, and four of them with adherence to the different cell lines were analyzed using a Scanning Electron Microscope (SEM). Thirty-one (89%) strains could adherent to at least one of the cell lines, adherence on Caco-2 cells was the most frequently observed (63%). Diffuse and aggregative adherence phenotypes similar patterns to those described for Escherichia coli, were observed in the trial. The SEM analysis showed in one of the strains, an amorphous structure in which a large number of bacteria were included. The SEM images of other three strains, showed the presence of bacterial projections that connect them with each other and with the cells. The results showed that Streptococcus sp. strains isolated from pozol, adhere to different epithelial cell lines likely through structures which may correspond to exopolysaccharides and/or surface adhesins in bacteria. The adherence ability of these bacteria to different cultured cells could be associated with different epithelial cell colonization and the possible use of these lactic acid bacteria as probiotics if the safe use is confirmed.