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標題: | 甲苯胺藍與甲殼素協同光動力殺菌對於金黃色葡萄球菌之懸浮菌體及生物膜之研究 Synergistic Photodynamic Inactivation of Toluidine Blue O and Chitosan on Staphylococcus aureus Planktonic and Biofilm Cells |
作者: | Hong-Sih Jiang 江紅思 |
指導教授: | 鄧麗珍 |
關鍵字: | 金黃色葡萄球菌,甲苯胺藍,甲殼素,光動力殺菌, Staphylococcus aureus,toluidine blue O,chitosan,photodynamic inactivation, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 隨著抗生素的濫用,許多細菌對抗生素產生了抗藥性,例如methicillin-
resistant Staphylococcus aureus (MRSA)的出現。隨著抗藥菌株的增加及多重抗藥菌株的出現,顯示出除了傳統的抗生素治療外,需要開發另一項抗菌方式來治療細菌的感染,例如光動力殺菌。光動力殺菌的原理是透過特定波長之光源將特定的光感物質加以激發,藉由電子之間的能量轉移產生自由基來毒殺細菌,或是藉由能量轉移至基態的氧分子形成激發單態的單態氧(singlet oxygen),攻擊細菌的細胞壁、細胞膜、核酸等結構。甲殼素(chitosan)為幾丁質(chitin)經處理及去乙醯化後所得,具有抑制細菌的特性,本實驗將探討甲殼素是否有協同光動力殺菌的作用。 由於世界各地的MRSA感染的比例有增加的趨勢,顯然在MRSA的治療方面有愈來愈大的挑戰性。微生物形成的生物膜對生物抑制劑的抗性比懸浮菌體高出100~1000倍以上,生物膜的防治在臨床上為一棘手的問題。本實驗以Staphylococcus aureus為對象,一株為ATCC 29213 (methicillin-sensitive S. aureus)、另一株為ATCC 33592 (MRSA),其他還挑選四株臨床的MRSA菌株。在光感物質方面所選用的為帶正電的Toluidine Blue O (TBO),利用紅色LED光源將此激發,探討TBO與甲殼素對於懸浮菌體與生物膜兩種狀態下的協同光動力殺菌成效。此外,也探究甲殼素協同TBO光動力殺菌對於S. aureus的protease活性之影響 。 經由實驗結果顯示,S. aureus懸浮菌體在TBO低濃度情況下,甲殼素已明顯有協同光動力殺菌作用;然而,生物膜菌體要在TBO較高濃度時甲殼素才會有協同殺菌效果。光動力作用對於生物膜的影響比懸浮菌體小,可能是生物膜的基因表現與特性有所不同所導致。未抗藥、抗藥菌株與不同SCCmec type之間對於協同光動力殺菌作用的感受性沒有明顯的差異,都具有甲殼素協同TBO光動力殺菌效果。甲殼素也具有抑制protease活性之成效。 Like the appearance of methicillin-resistant Staphylococcus aureus (MRSA), the developments of antibiotics-resistant events among a variety of bacteria are due to antibiotics abuses. Drug-resistant strains spring up like mushrooms that indicates antibiotics therapy not enough. To solve these problems, photodynamic inactivation is other anti-microbial strategies. Photodynamic inactivation employs visible light of appropriate wavelength to excite the photosensitizer and then the photosensitizer goes through a transition from ground state to triplet excited state. The triplet excited photosensitizer generates free radicals from electron transfer or reacts with oxygen molecules to produce singlet oxygen. Free radicals and singlet oxygen are toxic to bacteria because of destroying their components such as cell wall, cell membrane and nucleotides. Chitosan is from chitin undergoing deacetylation, and it exhibits antimicrobial effects. In this study, we investigated whether TBO combined with chitosan showed synergistic photodynamic inactivation. The trends of increasing prevalence of MRSA infections worldwide indicate that there are more challenges of MRSA therapy. Biofilms are 100 to 1,000 times less susceptible to antibiotics than planktonic bacteria, so it is difficult to handle biofilm prevention. This study focused on Staphylococcus aureus; one was ATCC 29213 (methicillin-sensitive S. aureus), another was ATCC 33592 (MRSA), and the others were four clinical MRSA strains. The photosensitizer was chosen cationic toluidine blue O (TBO) and then we used red LED light to excite it for evaluating the synergistic photodynamic inactivation efficiency of TBO combined with chitosan against planktonic and biofilm cells. In addition, this study also explored the influence of protease activity under TBO combined with chitosan treatment. The synergistic photodynamic inactivation for S. aureus planktonic cells could be detected under the conditions of low concentration of TBO; however, the effect for biofilm cells was only observed when TBO doses were increased. The synergistic photodynamic inactivation that was supposed to be associated with various genetic regulation and characteristics of bacterial stages affected biofilms less than planktonic cells. According to the results, there was no obvious difference of the synergistic photodynamic inactivation efficiency between methicillin-susceptible or resistant strains including diverse SCCmec types. Thus, the synergistic photodynamic activity by TBO combined with chitosan was shown in all of the tested S. aureus strains. Moreover, chitosan had the ability to inhibit protease activities of S. aureus. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/37684 |
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顯示於系所單位: | 醫學檢驗暨生物技術學系 |
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