以部花青素褐藻酸鈣晶球進行光動力作用處理流動狀態之金黃色葡萄球菌

由於抗生素的濫用，細菌抗藥性已成為世界共通問題，發展新的微生物防治法更是當務之急。光動力作用（Photodynamic action）是利用特定波長的光源來激發光感物質，不穩定的激發態將其能量轉換給周旁的氧分子後，進一步氧化細胞生物分子以造成破壞。早期光動力研究多著眼於癌細胞破壞，近年研究指出，此一機制在殺滅病毒、細菌乃至於真菌，亦有相當成效。然而，前人以光動力作用處理微生物多著眼於體外實驗，以不同光源激發各種光感物質來達到抗菌效果，或修飾光感物質的結構來加強與菌體間的親合性。近年來已有少數體內的局部測試，但在克服懸浮狀態下光動力作用對正常細胞的破壞仍有其瓶頸。此外，雖然已有研究選擇部花青素作為光感物質來處理微生物，但以細菌作為實驗材料仍屬少數。本實驗嘗試以褐藻酸鈣包埋部花青素以進行光動力作用處理Staphylococcus aureus與methicillin-resistant S. aureus (MRSA)，藉由部花青素藻膠晶球存在的孔隙來區隔細菌與正常血球細胞。結果顯示藻膠晶球直徑界於1.81－3.10 mm之間，取十顆晶球與濃度108 CFU/mL的菌液共振盪十分鐘後，約有1/10之菌數進入晶球。在光能量72 J/cm2的處理下，無論以部花青素原液50或100

關鍵字

MRSA ；固定化技術；發光二極體；光動力治療

並列摘要

Photodynamic antimicrobial chemotherapy (PACT), derived from photodynamic therapy (PDT), utilized photosensitizer (PS) and visible or ultraviolet light in order to give a phototoxic response, normally via oxidative damage to microorganisms. Because neither of the two major factors (lights and PSs) of the PACT is inherently bactericidal, it could be a useful and simple way to treat and control antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). Although lethal photosensitization of a wide range of microorganisms has been reported, the lack of specificity and inefficiency of light activation limit its application. The goal of this study is to establish a PACT system to treat flowing S. aureus and MRSA by immobilized PS that could be irradiated in vitro. Merocyanine 540 (MC540), a fluorescent dye that binds to the outer surface of the plasma membrane, had been widely used in blood sterilization and in inactivation against both planktonic culture and biofilm of S. aureus. In order to distinguish blood cells and bacteria, MC540 was immobilized by alginate beads to form porous medium which only allowed bacteria passed through. The characteristics of beads and the ability of MC540-alginate beads irradiated by green light emitting diode (LED) to inactivation flowing S. aureus strains in the circular reactor were reported. In addition, a blood sample containing S. aureus was also treated using this approach. The diameter of beads was between 1.81 and 3.10 mm. After 108 CFU/mL bacteria incubated with 10 alginate beads, there was around 1/10 bacteria bound to beads. In small scale treatment, when incident dose was up to 72 J/cm2, no viable cell of S. aureus was could be detected. In circular reactor, the best result of PACT treatment could suppress around 5 log CFU/mL. Although PACT showed minor inactivation in blood, this research showed a potential strategy of inactivation bacteria in blood and proposed a novel strategy by immobilizing photosensitizer to enhance PACT. This system was efficient to damage both wild type and antibiotic-resistant S. aureus.

並列關鍵字

LED ； light emitting diode ； methicillin-resistant Staphylococcus aureus ； photodynamic therapy ； immobilization ； MRSA

參考文獻

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以部花青素褐藻酸鈣晶球進行光動力作用處理流動狀態之金黃色葡萄球菌

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