Cell-Free Spent Media Obtained from Bifidobacterium bifidum and Bifidobacterium crudilactis Grown in Media Supplemented with 3′-Sialyllactose Modulate Virulence Gene Expression in Escherichia coli O157:H7 and Salmonella Typhimurium
| Autor: | Pauline Bondue, Georges Daube, Mansel W. Griffiths, François Brose, Sébastien Crevecoeur, Véronique Delcenserie, Gisèle LaPointe, Marie-Christine Seghaye |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Microbiology (medical) Salmonella Bifidobacterium longum 030106 microbiology ved/biology.organism_classification_rank.species lcsh:QR1-502 whey Virulence Salmonella enterica serovar Typhimurium virulence expression medicine.disease_cause Microbiology lcsh:Microbiology 03 medical and health sciences fluids and secretions medicine Bifidobacterium crudilactis Escherichia coli Original Research bovine milk oligosaccharide Bifidobacterium bifidum biology ved/biology Wild type food and beverages Pathogenic bacteria 3′-sialyllactose biology.organism_classification Salmonella enterica Escherichia coli enterohemorragic O157:H7 |
| Zdroj: | Frontiers in Microbiology Frontiers in Microbiology, Vol 7 (2016) |
| ISSN: | 1664-302X |
| DOI: | 10.3389/fmicb.2016.01460 |
| Popis: | Complex oligosaccharides from human milk (HMO) possess an antimicrobial activity and can promote the growth of bifidobacteria such as Bifidobacterium bifidum and Bifidobacterium longum subsp. infantis. In addition, fermentation of carbohydrates by bifidobacteria can result in the production of metabolites presenting an antivirulence effect on several pathogenic bacteria. Whey is rich in complex bovine milk oligosaccharides (BMO) structurally similar to HMO and B. crudilactis, a species of bovine origin, is able to metabolize some of those complex carbohydrates. This study focused on the ability of B. bifidum and B. crudilactis to grow in a culture medium supplemented in 3′-sialyllactose (3′SL) as the main source of carbon, a major BMO encountered in cow milk. Next, the effects of cell-free spent media (CFSM) were tested against virulence expression of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium. Both strains were able to grow in presence of 3′SL, but B. crudilactis showed the best growth (7.92 ± 0.3 log cfu/ml) compared to B. bifidum (6.84 ± 0.9 log cfu/ml). Then, CFSM were tested for their effects on virulence gene expression by ler and hilA promoter activity of luminescent mutants of E. coli and S. Typhimurium, respectively, and on wild type strains of E. coli O157:H7 and S. Typhimurium using RT-qPCR. All CFSM resulted in significant under expression of the ler and hilA genes for the luminescent mutants and ler (ratios of −15.4 and −8.1 respectively) and qseA (ratios of −2.1 and −3.1) for the wild type strain of E. coli O157:H7. The 3′SL, a major BMO, combined with some bifidobacteria strains of bovine or human origin could therefore be an interesting synbiotic to maintain or restore the intestinal health of young children. These effects observed in vitro will be further investigated regarding the overall phenotype of pathogenic agents and the exact nature of the active molecules. |
| Databáze: | OpenAIRE |
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