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

Abstract

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.

Candida Biofilm Eye Infection: Main Aspects and Advance in Novel Agents as Potential Source of Treatment

“…One feature that makes Candida spp. a very dangerous pathogen and difficult to treat is the ability to form biofilm on biotic and abiotic surfaces [ 16 ]. Biofilms consist in fungal cells immersed in a polysaccharide extracellular matrix, occasionally represented by the presence of hyphal cells [ 17 ].…”

“…However, in the case of strong suspicion, specific media can be used, such as Sabouraud agar, which allows a presumptive and early identification [ 3 ]. Growth in culture is considered significant if the same growth is obtained (i) on more than one occasion, (ii) on the ‘C’ streaks on more than one culture medium, or (iii) on one solid or in one liquid medium with direct microscopy of corneal material revealing the presence of yeast cells [ 16 ]. The material collected by corneal scraping can also be used for direct microscopic examination.…”

“…The main factor of virulence is the ability of microorganisms to form biofilms and produce adhesion factors that facilitate their permanence on lenses and containers [ 60 ]. Although FK accounts for only 1.5% of all cases of keratitis in contact lens users, the presence of fungi and the subsequent formation of biofilm in contact lenses poses an increasing threat to public health, especially for the ability of fungi to form polymicrobial biofilms, difficult to eradicate [ 7 ]. Most of Candida spp.…”

“…Fritsch et al, 2020 [ 16 ] studied the formation of biofilms on different types of contact lenses materials by C. albicans and C. krusei and the relative development of preventive or reductive treatment to avoid eye infections among contact lenses users. They found that both C. albicans and C. krusei strains were able to form biofilms on contact lenses, confirming the fact that they are a suitable surface for Candida spp.…”

“…Most Candida species can form biofilms on various types of contact lenses (CL), creating a physical barrier that confers antifungal resistance and CL maintenance solution [ 7 ].…”