Comparative analysis of biofilm formation by Candida albicans and Candida krusei in different types of contact lenses

ABSTRACT Objective: To evaluate the Candida krusei and Candida albicans biofilm formation abilities on 5 different types of contact lenses and compare their metabolic activities and biomass. Methods: After biofilm formation by both the test species, their metabolic activity was assessed by the 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide reduction assay with menadione, while the biomass was determined by staining with 0.4% crystal violet dye for further statistical analysis. Results: Both the Candida species could form biofilms on different types of contact lenses, with greater metabolic activities and lower biomass formation in rigid gas permeable lenses. Conclusion: Biofilm formation with greater metabolic activity and greater biomass were expected on soft contact lenses considering their surface hydrophobicity. However, the results demonstrated a greater metabolic activity on rigid contact lenses. This result has a great significance with regards to the increasing risk of microbial keratitis, although further studies are warranted to better elucidate the formation of biofilms on different types of contact lens materials in the future.

【摘要】 目的：评估克鲁斯假丝酵母菌（Candida krusei）与白色假丝酵母菌（Candida albicans）在5种不同类型隐形眼镜表面的生物膜形成能力，并比较二者的代谢活性与生物量。方法：待两种受试菌株形成生物膜后，采用添加甲萘醌的2,3-双(2-甲氧基-4-硝基-5-磺苯基)-2H-四唑-5-甲酰苯胺（XTT）还原试验评估其代谢活性；同时采用0.4%结晶紫染液染色测定生物量，用于后续统计分析。结果：两种假丝酵母菌均可在不同类型的隐形眼镜表面形成生物膜，且在硬性透气性隐形眼镜上的代谢活性更强、生物量生成更低。结论：鉴于软性隐形眼镜的表面疏水性，通常预期其表面会形成代谢活性更强、生物量更高的生物膜。但本研究结果显示，硬性隐形眼镜表面的代谢活性更高。该结果对于微生物性角膜炎风险升高的临床场景具有重要意义，不过未来仍需开展更多研究，以进一步阐明不同类型隐形眼镜材料表面的生物膜形成机制。