合併使用幾丁聚醣和抗真菌藥物Fluconazole對白色念珠菌和熱帶念珠菌及臨床分離抗藥性菌株具有協同殺菌效果

Synergistic antifungal activity of chitosan with fluconazole against Candida albicans and Candida tropicalis and its clinical isolates

羅唯瑄(Wei-Hsuan Lo)

指導教授 ： 林晉玄

國立臺灣大學/生命科學院/生化科技學系/碩士(2020年)

https://doi.org/10.6342/NTU202002301

摘要

白色念珠菌 (Candida albicans) 為人體常見的伺機性致病真菌，常存在於人體的口腔、生殖道、腸胃道及皮膚表面當中，當宿主免疫力低下或缺失時，便有可能造成入侵感染，甚至造成全身性感染進而死亡。目前在臨床上治療念珠菌感染的方式主要依靠抗真菌藥物的使用，但由於廣泛的使用抗真菌藥物，使得抗藥性菌株的出現逐漸增加，所以尋找新的治療方式有其重要性。有研究指出幾丁聚醣 (chitosan) 在pH低於6.3的情況下會帶正電，具有抗微生物的效果，且具有生物可降解性、生物相容性及低毒性等特性，有潛力開發作為新抗真菌治療方式，但目前幾丁聚醣的抗菌機制仍未明瞭。本研究致力研究白色念珠菌 (Candida albicans) 跟不同分子量的幾丁聚醣之間的相互關係，並將幾丁聚醣與抗真菌藥物結合，觀察兩者之間是否有協同殺菌作用 (synergistic antifungal effect) 。由實驗結果顯示，不同分子量的幾丁聚醣跟抗真菌藥物Fluconazole結合後，對白色念珠菌具有較好的協同抗菌效果。接著我們又測試了白色念珠菌臨床抗藥性分離株和不同物種的念珠菌熱帶念珠菌 (Candida tropicalis) 及其臨床分離抗藥性菌株，同樣發現將不同分子量的幾丁聚醣跟抗真菌藥物Fluconazole結合後，都具有較好的協同抗菌效果。本研究發現當抗真菌藥物Fluconazole跟幾丁聚醣結合後能夠以較低的劑量就達到抗菌效果，期待未來能進一步開發為新治療方式。

關鍵字

白色念珠菌 ； 幾丁聚醣 ； 抗真菌藥物 ； 協同抗菌作用 ； 熱帶念珠菌 ； 臨床分離抗藥性菌株

並列摘要

Candida species are wildly found in (on) human body, but they are able to shift from commensals to pathogens if the immune system is impaired. Challenges are the limited current therapeutic options for fungal infections and the potential adverse drug reactions. Besides, the available antifungal drugs are ineffective against new and drug-resistant strains. Thus, searching and development of new drugs or alternative therapeutic methods to control this fungus have become a demanding work. Chitosan, [poly-(β-1/4)-2-amino-2-deoxy-D-glucopyranose], derived from deacetylated chitin, has great potential against microbial infection owing to its biocompatibility, biodegradability, and low toxicity. However, the antimicrobial activity of chitosan is highly associated with the deacetylation degree, pH and its molecular weight. In this study, we investigated the antifungal activity of different types and properties of chitosan against Candida species. Results showed that fluconazole, but not amphotericin B and caspofungin, in combination with any one of chitosan is able to enhance antifungal activity against Candida albicans, Candida tropicalis, and its drug-resistant isolates. FICindex (fractional inhibitory concentration) performed by checkerboard assays also determined a synergistic antifungal activity against C. albicans, C. tropicalis, and its drug-resistant isolates when treatment with chitosan-fluconazole simultaneously. These findings provide a strong evidence that chitosan in combination with fluconazole is a promising therapy against Candida species and drug-resistant strains. The data also encourages further in vivo experiments to validate our findings, in which it will provide useful guidelines for us to develop a better way and formulation to manage fungal pathogens.

並列關鍵字

Candida albicans ； chitosan ； antifungal drug ； synergistic antifungal effect ； Candida tropicalis ； clinical isolates

參考文獻

1. Gow, N.A.R., A developmental program for Candida commensalism. Nature Genetics, 2013. 45(9): p. 967-968.

2. Weig, M., U. Groß, and F. Mühlschlegel, Clinical aspects and pathogenesis of Candida infection. Trends in microbiology, 1998. 6(12): p. 468-470.

3. Eggimann, P., J. Garbino, and D. Pittet, Epidemiology of Candida species infections in critically ill non-immunosuppressed patients. Lancet Infect Dis, 2003. 3(11): p. 685-702.

4. Martins, N., et al., Candidiasis: predisposing factors, prevention, diagnosis and alternative treatment. Mycopathologia, 2014. 177(5-6): p. 223-240.

5. Hesstvedt, L., et al., The impact of age on risk assessment, therapeutic practice and outcome in candidemia. Infectious Diseases, 2019. 51(6): p. 425-434.