Lau, Li Ying Jessie (2018) Antagonistic activity of lactobacillus plantarum 0612 against selected foodborne enteropathogens. Masters thesis, Universiti Malaysia Sabah.
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Abstract
Probiotic has been previously used for the treatment and prevention of intestinal disorders caused by enteropathogens. However, the antagonistic effect of probiotic on these pathogens in the gastrointestinal tract is not fully understood. The study aims to investigate the antagonistic ability of a probiotic strain, Lactobacillus plantarum 0612 against the adhesion of selected foodborne enteropathogens (Escherichia coli ATCC 11775, Salmonella Enteritidis ATCC 13076, Listeria monocytogenes ATCC 13932 and Vibrio parahaemolyticus ATCC 17802) to the colon epithelial Caco-2 cells by exclusion, competition and displacement conditions. L. plantarum 0612 has been subjected to the gastrointestinal transits simulation (GITS) sequentially prior to assess its competitive inhibition on selected human pathogenic strains using intestinal epithelial cells with different colonic pH conditions. The surface layer proteins that are involved in adhesion inhibition were separated using SDS-PAGE and further identified by MALDI-TOF/MS. Results showed that the adhesion of E. coli and L. monocytogenes on to Caco-2 cells was significantly inhibited by L. plantarum 0612 with a reduction of 4.35 log CFU/ml and 4.14 log CFU/ml, respectively in exclusion mechanism. However, L. plantarum 0612 exhibited a significantly stronger (p<0.05) competition activity against V. parahaemolyticus as compared to its exclusion and displacement activity. The exclusion and competition mechanisms seemed to be more effective against the colonization of E. coli in the presence of L. plantarum 0612. The GITS exposed L. plantarum 0612 showed significantly higher (p<0.05) efficacy of competitive inhibition against the selected foodborne enteropathogens in all colonic conditions as compared to the unexposed strain. The highest antagonistic activity was observed against the adhesion of E. coli and V. parahaemolyticus on the Caco-2 cells, with a log reduction of 5.10 log CFU/ml and 4.53 log CFU/ml respectively, in the colonic pH 5.0 after 8 hours of exposure. However, the GITS exposed L. plantarum 0612 significantly reduced (p<0.05) the adhesion of L. monocytogenes (4.20 log reduction) and S. Enteriditis (4.12 log reduction) respectively in the same colonic condition. It seems the colonic pH of the intestines could influence the antagonism of L. plantarum 0612 with the highest antiadhesion against the bacterial pathogens was shown at pH 5.0 and 6.0, signifying the protective role of probiotic in the human proximal colon. Six cell surfaceassociated proteins (30s ribosomal protein, ATP synthase subunit beta, enolase, phosphoglycerate kinase, lactate dehydrogenase, and glycealdehyde-3-phosphate dehydrogenase) and 6 adhesive moonlighting proteins, (elongation-factor Tu, 60 kDa chaperonin GroEL, pyruvate kinase, triosephosphate isomerase, and 2, 3 bisphosphoglycerate-dependant phosphoglycerate mutase fructose-bisphosphate aldolase) have been identified using MALDI-TOF/TOF mass spectrometry. The expression of these adhesive surface proteins seemed to be influenced by the colonic pH conditions. Therefore, the existing of surface adhesive proteins in L. plantarum 0612 is expected to be responsible for its adhesion and antagonistic effects against the foodborne enteropathogens in human colonic epithelial cells. The excellent adherence and the antagonistic properties of L. plantarum 0612 against the enteropathogens are promising for the prevention and management of foodborne infections/diseases.
| Item Type: | Thesis (Masters) |
|---|---|
| Keyword: | Lactobacillus plantarum 0612, Probiotic, Foodborne pathogens, Antagonistic effect, Adhesion inhibition, Gastrointestinal transit simulation |
| Subjects: | Q Science > QR Microbiology > QR1-502 Microbiology > QR180-189.5 Immunology |
| Department: | FACULTY > Faculty of Food Science and Nutrition |
| Depositing User: | DG MASNIAH AHMAD - |
| Date Deposited: | 25 Mar 2025 10:08 |
| Last Modified: | 25 Mar 2025 10:08 |
| URI: | https://eprints.ums.edu.my/id/eprint/43317 |
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