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Open Access Research article

In vitro adhesion and invasion inhibition of Shigella dysenteriae, Shigella flexneri and Shigella sonnei clinical strains by human milk proteins

Emerson da Motta Willer1, Renato de Lourenço Lima2 and Loreny Gimenes Giugliano1*

Author Affiliations

1 Laboratório de Microbiologia, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, 71910-900, Brasília-DF, Brazil

2 Hospital Universitário de Brasília, Departamento de Pediatria, Banco de Leite, Universidade de Brasília 71910-900, Brasília-DF, Brazil

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BMC Microbiology 2004, 4:18  doi:10.1186/1471-2180-4-18

Published: 28 April 2004

Abstract

Background

Shigella is the etiological agent of shigellosis, a disease responsible for more than 500,000 deaths of children per year, in developing countries. These pathogens colonize the intestinal colon, invade, spreading to the other enterocytes. Breastfeeding plays a very important role in protecting infants from intestinal infections. Amongst milk compounds, glycosylated proteins prevent the adhesion of many enteropathogens in vitro. The aim of this work was to determine the effect of human milk proteins on the colonization potential of Shigella dysenteriae, S. flexneri and S. sonnei. To fulfill this purpose, pooled milk samples from five donors, were fractionated by gel filtration and affinity chromatography. Using tissue culture, the milk fractions obtained were tested in Shigella adhesion and invasion assays.

Results

Our revealed showed that both adhesion and invasion of Shigella species were inhibited by low concentration of secretory immunoglobulin A, lactoferrin and free secretory component. This work also showed that, these proteins bind to superficial and whole-cell Shigella proteins.

Conclusions

Our findings suggest that human milk may act inhibiting adhesion and, consequently, invasion of Shigella, thereafter preventing shigellosis in infants.