2012年9月17日 訊 /生物谷BIOON/ --近日,，來自美國科學(xué)家一項(xiàng)最新的研究成果揭示了一種新型的微流體技術(shù),，用于快速進(jìn)行金黃色葡萄球菌的抗生素敏感性檢測。相關(guān)研究成果刊登在了國際雜志Lab on a Chip上,。
我們都知道,，金黃色葡萄球菌（Staphylococcus aureus）是一種耐藥性極強(qiáng)的革蘭氏陽性球菌，其在自然界隨處都可以發(fā)現(xiàn),。該菌由于可分泌包括溶血素,、外毒素等多種毒素，可引起人類嚴(yán)重的組織感染,。近些年來由于抗生素的不合理使用,，使得金黃色葡萄球菌的耐藥性逐漸上升，因此開發(fā)出有效的治療手段以及快速的抗生素耐藥性檢測技術(shù)對于科學(xué)家來說迫在眉睫,。
本文研究就揭示了一種新型的金黃色葡萄球菌抗生素敏感性的快速檢測方法,。隨著細(xì)菌對抗生素耐藥性的不斷增加，依賴于觀察細(xì)菌生長抑制的標(biāo)準(zhǔn)方法對于當(dāng)前的抗生素并不適用,，因此研究者開發(fā)出了一種新型的微流體平臺來進(jìn)行細(xì)菌對抗生素的敏感性測試,，此技術(shù)基于細(xì)菌在生物合成過程中的壓力激活作用，細(xì)菌的這些生物合成過程是研究者最初的抗生素靶點(diǎn),。
研究者使用金黃色葡萄球菌（S. aureus）作為模式對象,，同時選擇細(xì)菌細(xì)胞壁的合成作為壓力和抗生素的作用靶點(diǎn)來進(jìn)行研究。酶類和物理壓力都可以損傷細(xì)菌的細(xì)胞壁,，β-內(nèi)酰胺類抗生素可以干擾細(xì)胞壁的修復(fù)過程,，最終導(dǎo)致無耐藥性的細(xì)菌細(xì)胞的死亡,，細(xì)菌細(xì)胞的死亡可以使用熒光標(biāo)記技術(shù)來進(jìn)行追蹤觀察，死亡比例可以通過在系統(tǒng)中添加或不添加苯唑西林來進(jìn)行測定,。
研究者Alexis F. Sauer-Budge表示,，我們開發(fā)出了一種新型的基于微流體檢測和壓力激活的藥敏試驗(yàn)的新型技術(shù)，在未來臨床試驗(yàn)中,，這種新型技術(shù)可以幫助研究者檢測細(xì)菌的多種壓力效應(yīng)以及抗生素敏感性,，對于臨床治療細(xì)菌性感染具有重要的價值。（生物谷Bioon.com）
doi:10.1039/C2LC40531H
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A microfluidic platform for rapid, stress-induced antibiotic susceptibility testing of Staphylococcus aureus
Maxim Kalashnikov , Jean C. Lee , Jennifer Campbell , Andre Sharon and Alexis F. Sauer-Budge
The emergence and spread of bacterial resistance to ever increasing classes of antibiotics intensifies the need for fast phenotype-based clinical tests for determining antibiotic susceptibility. Standard susceptibility testing relies on the passive observation of bacterial growth inhibition in the presence of antibiotics. In this paper, we present a novel microfluidic platform for antibiotic susceptibility testing based on stress-activation of biosynthetic pathways that are the primary targets of antibiotics. We chose Staphylococcus aureus (S. aureus) as a model system due to its clinical importance, and we selected bacterial cell wall biosynthesis as the primary target of both stress and antibiotic. Enzymatic and mechanical stresses were used to damage the bacterial cell wall, and a β-lactam antibiotic interfered with the repair process, resulting in rapid cell death of strains that harbor no resistance mechanism. In contrast, resistant bacteria remained viable under the assay conditions. Bacteria, covalently-bound to the bottom of the microfluidic channel, were subjected to mechanical shear stress created by flowing culture media through the microfluidic channel and to enzymatic stress with sub-inhibitory concentrations of the bactericidal agent lysostaphin. Bacterial cell death was monitored via fluorescence using the Sytox Green dead cell stain, and rates of killing were measured for the bacterial samples in the presence and absence of oxacillin. Using model susceptible (Sanger 476) and resistant (MW2) S. aureus strains, a metric was established to separate susceptible and resistant staphylococci based on normalized fluorescence values after 60 min of exposure to stress and antibiotic. Because this ground-breaking approach is not based on standard methodology, it circumvents the need for minimum inhibitory concentration (MIC) measurements and long wait times. We demonstrate the successful development of a rapid microfluidic-based and stress-activated antibiotic susceptibility test by correctly designating the phenotypes of 16 additional clinically relevant S. aureus strains in a blinded study. In addition to future clinical utility, this method has great potential for studying the effects of various stresses on bacteria and their antibiotic susceptibility.
