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標題: | CX加強抗生素對革蘭氏陰性菌的殺菌效果之機制探討 Action Mechanism of CX in Increasing the Bactericidal Effect by Antibiotics on Gram-negative Bacteria |
作者: | YA-I Yang 楊雅怡 |
指導教授: | 陳進庭(Chin-Tin Chen) |
關鍵字: | 抗生素,最低抑制濃度,生物膜,革蘭氏陰性菌, Antibiotics,Minimum inhibitory concentration,Biofilm,Gram-negative, |
出版年 : | 2009 |
學位: | 碩士 |
摘要: | 臨床上,目前普遍使用抗生素治療因革蘭氏陰性菌所引起的感染症,這樣的治療方法缺點在於抗生素的濫用帶來的篩選壓力,使得抗藥性細菌出現。革蘭氏陰性菌具有多重的抗藥性機制,一旦發現抗藥性菌株大多已是多重抗藥性菌株,造成後續治療上的困難。本實驗室先前研究發現,CX能有效加強光動力的殺菌效果,希望藉由CX的協助加強抗生素對革蘭氏陰性菌的殺菌效果,降低抗生素的使用量。
研究發現,CX和抗生素作用與抗生素單獨使用時相比較,發現能多降低7個log值生菌數而達全殺的效果,而且加入CX於不同抗生素的MIC濃度時,最終達到的殺菌效果顯著比使用MIC以上濃度的殺菌效果更好,因此CX可加強不同種類的抗生素對革蘭氏陰性菌之殺菌效果,同時亦能協助降低抗生素使用劑量;CX的加強殺菌效果也對抗藥性菌株有效,但CX無法加強EDTA在綠膿桿菌的殺菌效果。至於應用在綠膿桿菌的生物膜殺菌上,可能是受到胞外聚合物的阻礙使CX無法進入生物膜與細菌接觸,因此無法如同在懸浮培養上有增強殺菌的效果。未來實驗室計劃將朝向改良CX的性質與破壞生物膜表面的胞外聚合物,再觀察CX在抗生素對生物膜上的殺菌效果之影響 Antibiotics are the most popular antimicrobial agent used for the treatment of infection caused by Gram-negative bacteria. However, drug-resistance is a growing problem largely due to the widespread use of antibiotics in medicine. The opportunistic Pseudomonas aeruginosa (P. aeruginosa) is one of Gram-negative bacteria, which has been identified several drug-resistant strains in clinics. Therefore, it is necessary to develop an alternative antimicrobial technique which is effective in the treatment of multi-drug resistant bacteria infections. In the presence of compound X (CX), we have previously found that hematoporphyrin (Hp)-mediated photodynamic inactivation (PDI) could increase the bacterial killing against Gram-positive as well as Gram-negative bacteria. In this study, we further address whether CX can exert synergistic antimicrobial effect in antibiotics against Gram-negative bacteria. We found that CX can synergistically increase the antibiotics-mediated bactericidal effects. Under the MIC concentration, the bacterial effect of Polymyxin B 、 Colistin 、 Imipenem 、Gentamicin and Ciprofloxacin is around 2~3 log against P. aeruginosa in platonic culture; however, complete killing could be found in the presence of 0.25% CX. Similar results were also found in other Gram-negative bacterial, Acinetobacter baumannii。However, this synergistic effect of antibiotics and CX was not found in biofilm study, which might relate to the extracellular polymeric substances of biofilm. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/43392 |
全文授權: | 有償授權 |
顯示於系所單位: | 微生物學科所 |
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