| Summary: | 碩士 === 國立臺灣大學 === 食品科技研究所 === 103 === Staphylococcus aureus is a common foodborne pathogen causing food poisoning and also the major pathogen of nosocomial infections at the same time. The main reason for causing infections of S. aureus is the ability of forming biofilm on the food processing equipment and medical devices. Biofilm is a microbially-derived sessile community; they have different performance mechanism individually in physiological characteristics and toxicity, increasing drug resistance and the resistance ability of the immune system compare to the planktonic cells. Previous studies reported that tea leaves extracts have the potential to inhibit biofilm formation of Streptococcus mutans, a major bacteria of dental decay on the surface of teeth. Thus, this study will extract and separate the different bioactive compounds from tea waste, investigate their antimicrobial activity and inhibition of S. aurues biofilm production. As the result, EA-F3 fraction which consists of large amounts of tea saponin, is capable to inhibit the growth of three tested S. aureus and its MIC, 0.5 mg/ml, also effective on inhibit S. aureus biofilm formation. At the same time, EA-F2 fraction that composed of tea polyphenol also effective on the antimicrobial and inhibition of biofilm formation with MIC, 0.5 mg/ml. But the results are different among three of the tested strains. The observation with scanning electron microscope showed that S. aureus grew loose and scattered, less secretion of polysaccharides after treated with both fractions. However, both EA-F2 and EA-F3 fraction could not remove the pre-formed biofilm with the same concentration or the increasing concentrations.
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