title: Adhesion to the yeast cell surface as a mechanism for trapping pathogenic bacteria by Saccharomyces probiotics.
abstract: Recently, much attention has been given to the use of probiotics as an adjuvant for the prevention or treatment of gastrointestinal pathology. The great advantage of therapy with probiotics is that they have few side effects such as selection of resistant bacteria or disturbance of the intestinal microbiota, which occur when antibiotics are used. Adhesion of pathogenic bacteria onto the surface of probiotics instead of onto intestinal receptors could explain part of the probiotic effect. Thus, this study evaluated the adhesion of pathogenic bacteria onto the cell wall of Saccharomyces boulardii and Saccharomyces cerevisiae strains UFMG 905, W303 and BY4741. To understand the mechanism of adhesion of pathogens to yeast, cell-wall mutants of the parental strain of Saccharomyces cerevisiae BY4741 were used because of the difficulty of mutating polyploid yeast, as is the case for Saccharomyces cerevisiae and Saccharomyces boulardii. The tests of adhesion showed that, among 11 enteropathogenic bacteria tested, only Escherichia coli, Salmonella Typhimurium and Salmonella Typhi adhered to the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741. The presence of mannose, and to some extent bile salts, inhibited this adhesion, which was not dependent on yeast viability. Among 44 cell-wall mutants of Saccharomyces cerevisiae BY4741, five lost the ability to fix the bacteria. Electron microscopy showed that the phenomenon of yeast-bacteria adhesion occurred both in vitro and in vivo (in the digestive tract of dixenic mice). In conclusion, some pathogenic bacteria were captured on the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741, thus preventing their adhesion to specific receptors on the intestinal epithelium and their subsequent invasion of the host.
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: F C P
authors.initials: FCP
authors.lastname: Tiago
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: F S
authors.initials: FS
authors.lastname: Martins
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: E L S
authors.initials: ELS
authors.lastname: Souza
authors.affiliation: Laboratório de Entomologia Médica, Instituto René Rachou, Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: P F P
authors.initials: PFP
authors.lastname: Pimenta
authors.affiliation: Laboratório de Entomologia Médica, Instituto René Rachou, Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: H R C
authors.initials: HRC
authors.lastname: Araujo
authors.affiliation: Núcleo de Pesquisa em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: I M
authors.initials: IM
authors.lastname: Castro
authors.affiliation: Núcleo de Pesquisa em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: R L
authors.initials: RL
authors.lastname: Brandão
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Nicoli
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology*; D002473:Cell Wall / Q000382:microbiology*; D004926:Escherichia coli / Q000502:physiology*; D006801:Humans; D007422:Intestines / Q000382:microbiology; D051379:Mice; D016688:Mice, Inbred NOD; D019936:Probiotics / Q000378:metabolism*; D012440:Saccharomyces / Q000145:classification / Q000502:physiology*; D012486:Salmonella typhimurium / Q000502:physiology*