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ANNUAL CONFERENCE :: Abstract Library
Abstract Library
2003 Conference Abstract
| Type of Submission |
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Submission Type: |
Poster Presentation |
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Subject Category: |
Applied Microbiology |
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| Session Information |
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Presentation Date: |
May 26, 2003 |
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Abstract ID: |
A25 |
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Session: |
Poster 1 |
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Time: |
14:00 |
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| Presenting Author |
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| Other Authors |
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M LACROIX, INRS-Institut Armand-Frappier
D ARCHAMBAULT, Université du Québec à Montréal
L LAMONTAGNE, Université du Québec à Montréal
D ROY, Centre de recherche et de développement sur les aliments
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| Title |
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Inhibition of pathogens by lactic acid bacteria strains in fermented milk and mice C57BL/6 |
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| Abstract Text |
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The inhibition potential of selected lactic acid bacteria (LAB) (Lactobacillus rhamnosus RW-9595M, L. rhamnosus ATCC 9595, Lactococcus lactis subsp. lactis ATCC 11454 and the commercial starter culture CL 1285) on the growth of various pathogens and indicators strains was evaluated. Growth inhibition was first demonstrated using an "agar spot test" and a "well-diffusion assay". In separate experiments, proteases were added to verify that the inhibition is caused by a proteinaceous substance. Thereafter, the selected LAB strains were added (at a ratio of 104:1) in skim milk to compete with the pathogens (Escherichia coli, Staphylococcus aureus, Salmonella typhymurium, Listeria innocua). Without pH control, growth inhibition of the different pathogens occurred in 24 to 48 hours while the lactobacilli grew to 108-109 CFU/ml. Under stabilized pH to 6.5 during the fermentation process, the growth rate of pathogens was reduced by 1 to 4 log UFC/ml in 48 hours as compared to the control (pathogen alone). An increase of pathogen generation time was also observed. Moreover, the immunological effect of the LAB was assayed on C57BL/6 mice macrophages. LAB seemed to be able to modulate the macrophagic activity. These results were an indication that the pathogens inhibition is not only related to acid production. In conclusion, all LAB used in this study exerted an antimicrobial activity and can thus be considered as a potential biotherapeutic remediation of patients infected with intestinal pathogens. |
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