結合光動力殺菌與Fluconazole在白色念珠菌的治療效果探討

Abstract

近年來真菌感染的患者日益據增，尤其以白色念珠菌(Candida albicans)最為常見，而抗真菌藥物的過度頻繁使用，也引發抗藥性問題。因此許多研究開始尋找其他的治療方法，像是兩種藥物的合併使用等。光動力殺菌(Photodynamic inactivation, PDI)是不同於以藥物治療微生物感染的方式，透過光反應產生單態氧與自由基對微生物造成傷害。本研究以PDI結合Fluconazole的方式，期望透過PDI增強Fluconazole對白色念珠菌的殺菌效果，降低藥物使用劑量，減少抗藥性產生機會。 在本研究中，發現PDI對於白色念珠菌之懸浮細胞具有殺菌效果，且PDI造成的damage程度越嚴重，菌體需要修復的時間就越長，越晚進入log phase。實驗結果也發現PDI結合Fluconazole能增強對白色念珠菌的殺菌效果，降低藥物使用劑量。進一步發現以TBO 0.1 mM進行PDI後，如果不於2小時內加入Fluconazole，菌體會有修復損傷情形，無法達到增強殺菌效果。類似的增強殺菌效果也在PDI結合Posaconazole的研究中發現。此外，結合PDI和Fluconazole對白色念珠菌的臨床抗藥性菌株，也會有協同性的殺菌效果。最後，應用在白色念珠菌的生物膜殺菌上，無法像在懸浮培養上有明顯的增強殺菌效果。未來將朝向生物膜表面的胞外聚合物破壞程度與藥物作用性質，探討如何進一步結合PDI和Fluconazole來增強對生物膜的殺菌效果。

In recent years, infection of pathogenic fungus, especially Candida albicans, has increased gradually in patients. Antifungal drugs have been frequently used to treat these infections; however, side effects of antifungal drugs as well as drug resistance gradually become serious issues. Therefore, it is important to find an alternative treatment modality for fungal infection. Photodynamic inactivation (PDI), combination of a nontoxic photosensitizer (PS) and light, could produce free radicals or singlet oxygen that are toxic to pathogens. In this study, we found that the combination of PDI and Fluconazole could synergistically increase the antifungal activity against C. albicans. Compared to C. albicans without PDI treatment, the growth curve of C. albicans survived from PDI remained in lag phase longer and this retention correlated with the PDI dose. Furthermore, we found that the augmented antifungal activity will decrease if the addition of Fluconazole was performed two hours after PDI. Similar augment antifungal activity was also found in the combination of PDI and Posaconazole. Although higher TBO concentration is required to exert its PDI efficacy, the synergistic fungicidal efficacy was also found in drug-resistant strains.