Title Page
Contents
Abstract 9
Introduction 12
Materials and Methods 16
1. Materials 16
2. Preparation of chitosan-phytochemical conjugates 16
3. Bacterial strains and culture conditions 19
4. Evaluation of antibacterial activity of chitosan-phytochemical conjugates 21
5. Antibiotic susceptibility of fish pathogenic bacteria 22
6. Fractional inhibitory concentration (FIC) assay using checkerboard method 22
Results and Discussion 24
1. Antibacterial activity of chitosan-phytochemical conjugates against fish pathogenic bacteria 24
2. Antibiotic resistance of fish pathogenic bacteria 25
3. Synergy effects between chitosan-phytochemical conjugate and antibiotics against fish pathogenic bacteria 31
Conclusion 44
References 46
Appendix 56
Table 1. Bacterial strains used in this study 20
Table 2. Minimum inhibitory concentration (MIC) of chitosan-phytochemical conjugates agaisnt fishpathogenic bacteria 28
Table 3. Antibiotic susceptibility of fish pathogenic bacteria. 29
Table 4. Minimum inhibitory concentration (MIC) for ampicillin, erythromycin and... 30
Table 5. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of the chitosan-phytochemical conjugates... 34
Table 6. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 35
Table 7. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 36
Table 8. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 37
Table 9. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 38
Table 10. Minimum inhibitory concentarion (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjuages in... 39
Table 11. Minimum inhibitory concentartion (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 40
Table 12. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjuagtes in... 41
Table 13. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 42
Table 14. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) indices of chitosan-phytochemical conjugates in... 43
Fig. 1. Synthesis pathway of chitosan-phytochemical conjugates 18
Fig. 2. Fractional inhibitory concentration (FIC) index andcalculation 23