| Author: | Tsang, Chun Ho |
| Title: | Investigation the anti-microbiale effects of Rhizoma Zingiberis Recens (RZR) and Rhizoma Atractylodis (RA) on Escherichia coli (E.coli), Extended spectrum beta lactamase (ESBL) E. coli, Staphylococcus aureus (SA) and Methicillin-resistant Staphylococcus aureus (MRSA) |
| Degree: | M.Sc. |
| Year: | 2014 |
| Subject: | Herbs -- Therapeutic use -- Testing. Medicine, Chinese. Escherichia coli. Beta lactamases. Enterobacteriaceae. Staphylococcus aureus. Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Health Technology and Informatics |
| Pages: | xiv, 92 leaves : illustrations ; 30 cm |
| Language: | English |
| Abstract: | Introduction: Herbal or plant products are potential natural choices for treating bacterial infections. They have the advantage of fewer side effects, and are less harmful to humans compared with synthetic Western medicines. Objective: This study proposes using the track dilution method to determine the antimicrobial effect of Rhizoma Zingiberis Recens (RZR) and Rhizoma Atractylodis (RA) on Escherichia coli (E. coli), Extended-spectrum beta lactamase (ESBL) E. coli, Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA), with various concentrations of RZR and RA. We investigated 10 clinical isolates of ESBL E. coli, MRSA, E. coli ATCC 25922 and SA ATCC 25923. Methods: Bacteria strains used in the project were identified through Gram staining, biochemical tests and antibiotic susceptibility tests. Growth curves of each strain of SA, MRSA, E. coli and ESBL E. coli were established to estimate the time of each bacteria stain reached the mid-log phase. Standard curve of each strain of SA, MRSA, E. coli and ESBL E. coli were established to determine the initial number of bacteria present in the nutrient broth by measuring the optical density of the broth. The antimicrobial effect of RA and RZR on bacterial strains was determined through track dilution method. Propidium iodide (PI) staining was done to investigate the inhibitory mechanism of RA or RZR on the bacteria. The stained bacterial cells indicated the existence of membrane inhibition. Results: The result in a 99.9% reduction in the initial inoculum (i.e., a 3-log10 reduction in colony-forming units per milliliter) on subculture usually regarded as a significant reduction of CFU. We conducted the Kruskal-Wallis test and Dunn multiple-comparison tests using Prism software and analyzed the results. RA and RZR leaded to 1 to 3 log10 reduction in CFU/ml at low concentration of RA and RZR (i.e., 50mg/ml) on SA ATCC 25923 and 10 strains of MRSA compared with the water control after 24-hour incubation. The reduction of CFU/ml increased with the increment of RA and RZR concentration treatment. RA (i.e., 350mg/ml) leaded to a maximum of 4 to 5 log10 reduction in CFU/ml and RZR (i.e., 75 to 100mg/ml) leaded to a maximum of 7 to 9 reduction in CFU/ml. Only RZR (i.e., 500mg/ml) leaded to a maximum of 3 to 4 log10 reduction in CFU/ml on 2 strains of ESBL E. coli. The PI staining results indicated that RA inhibited all MRSA and SA strains through membrane inhibition, whereas only 5 strains of MRSA were inhibited by RZR through membrane inhibition. Conclusion: Our results indicated that RA and RZR exerted an inhibitory effect on all SA and MRSA strains, and that this effect was dose dependent. It had an RZR inhibitory effect only on 2 strains ESBL E. coli. |
| Rights: | All rights reserved |
| Access: | restricted access |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| b27590045.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.08 MB | Adobe PDF | View/Open |
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