病原菌在大自然的環境中無所不在，尤其常存在我們的食物和飲用水中，甚至人體的鼻腔黏膜或皮膚接觸空氣的地方也均有其存在，然當人體的免疫功能下降時使微生物得以入侵到人體內，據此即造成古今影響世界歷史，且對人類威脅甚巨的『感染或瘟疫』。約85年前起抗生素的逐項發明，使人類對抗感染取得一時或階段性的勝利，惟在濫用下的後果，抗藥性細菌也逐漸被篩檢出來，尤以院內感染引起的問題與日俱增。但醫師面對緊急病患卻常需在未知何種病原菌感染情形下先行用藥，繼而對患者進行密切的臨床變化觀察，同時也苦待需時兩天以上的傳統檢驗報告，此狀況下延續至今即會有相當比例的患者無法獲救。如腸桿菌屬是常見的格蘭氏陰性(G(-))菌，可能導致血液感染、腹腔感染、肺炎、泌尿道感染等，自20世紀末，尤其大腸桿菌(E. coli)和肺炎克雷伯氏菌(Klebsiella pneumonia, K. p)，對頭孢菌類抗生素產生抗藥性，導致抗廣效型頭孢菌素失效。不幸的是新型抗生素發展無法如此快速產生，且也未必能抑制所有細菌，甚或誘發多重抗藥性(multidrug resistance, MDR)細菌，例如具New Delhi metallo-beta-lactamase-1 (NDM-1)基因細菌已然出現在世界各地，如今只有Colistin和Tigecycline可以抑制。因此適當和合理使用抗生素，避免藥物濫用、減少抗藥性細菌，是抗生素藥敏性測試(AST)的重要目標。然傳統上對於細菌的抗藥性測試，係採用培養法(如Broth dilution, Disc diffusion或E-test)，通常需16~24小時，甚或需要幾天時間，始能得知診斷結果，因此AST效率要如何提高即成重要課題。如今已邁入21世紀十餘年了，特別是在這講求個人化醫療聲中，快速檢測且正確的判知極被盼望，能讓治療與診斷趨於無縫相接，且又不違背傳統法的檢測原則之新方法開發，有其急迫重要性。目前傳統抗生素敏感性檢測需要兩到三天時間，為求快速藥敏試驗，本研究發展一種簡易製作且方便操作晶片，本研究針對G(-)致病菌進行藥敏性檢測。由於頭孢菌類抗生素會抑制細菌細胞壁之分裂，產生菌體延長現象，受到藥物抑制細菌(較長)，受電場作用呈現吸附力(正介電泳力)；未被抑制細菌(較短)，受電場作用則呈現排斥力(負介電泳力)。整個檢驗過程可於2小時之內檢測出最小抑制濃度，相較於傳統培養方式(需數天)可大幅地縮短時間。

In this research, we describe the use of dielectrophoretic (DEP) technique to analyze the resistance of pathogens to antibiotics and to determine the minimum inhibitory concentration in order to achieve fast and accurate diagnosis. Bacterial cell wall synthesis is inhibited by beta-lactam antibiotics which causes the phenomenon of bacterial cell elongation. The elongated bacteria possess distinctive DEP properties which has a strong electric dipole force on both longitudinal sites. In this study, we concluded that DEP characteristic frequency will be significantly changed as the bacterial growth is inhibited by antibiotic. If bacteria resistant to antibiotic treatment and bacterial shape remain, there will be no change in its characteristic frequency. This method is not only able to distinguish the resistance ability of bacteria and its characteristic frequency changes upon different concentration of drug treatment also the minimum inhibitory concentration of the pathogen. In addition, the entire experimental process of can be executed within two hours, which can significantly shorten the testing time. Antibiotic containing culture medium was diluted with consistent process and clinically important pathogen was tested with DEP based antimicrobial susceptibility tests. Fabrication of the chip is very simple and low cost requirements. Gram negative bacteria have been important pathogen in clinical infections and often carry multiple drug resistance, and often been treated by the beta-lactam antibiotic. Therefore, it could be used in clinical diagnosis, compared to the traditional culture method; the whole testing time can significantly be shortened to be in 2 hr.

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