First Author: S.Saha INDIA
Co Author(s): J. Sengupta A. Khetan D. Banerjee
Purpose:
To demonstrate the in vitro ability of biofilm formation on contact lens and antifungal susceptibility pattern of three keratitis associated mold pathogens- Aspergillus fumigatus, Fusarium solanii, Alternaria sp and two yeasts- Candida albicans and Rhodotorula sp.
Setting:
Tertiary eye care center of eastern India
Methods:
Fungal species were collected from mature solid medium culture plate and mixed with liquid RPMI 1640 and incubated for 24 hrs to get relevant turbidity. To evaluate the biofilm formation of all isolates, soft contact lenses were submerged in 96 wells, flat bottom, polystyrene plates containing medium, inoculated with respective fungal strains. After 72 hrs the lenses were removed and the planktonic cells were washed gently with buffer. The developed biofilms were then analyzed by fluorescence microscopy. A semi quantitative measure of biofilm formation was calculated by XTT reduction assay. Comparative minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) were noted against antifungals used for topical therapy.
Results:
Fluorescence microscopy using concanavalin showed that all selected fungal species formed biofilms. Quantification data revealed that Candida albicans and Rhodotorula sp were able to make a large amount of biomass after 72h incubation followed by Aspergillus fumigatus and Alternaria sp. The biofilm growth curve showed that all strains required minimum 6h in their developmental phase over soft contact lenses and showed very low metabolic activity in the first 12 hrs. Mature biofilm formation was observed within 72h incubation for all the strains. After forming the biofilm MBEC was increased several fold compared to MIC.
Conclusions:
We established an in vitro model of three filamentous fungi and two yeast biofilm formation on contact lenses. The common antifungals do not have the capability of breaking the biofilm.This in vitro model will be helpful for better understanding the pathogenesis of fungal keratitis. FINANCIAL DISCLOSURE?: No
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