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Mixed Candida albicans-Staphylococcus aureus Biofilm Is Reduced by Light-Activated Nanocomposite with Phloxine B
Jarmila Czucz Varga1, Juraj Bujdák2,3, Helena Bujdáková1
1Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia.
Abstract:
Candida albicans and Staphylococcus aureus are opportunistic pathogens that cause life-threatening infections. This study focused on using photodynamic inactivation (PDI) to eliminate mixed biofilms of C. albicans-S. aureus formed on poly (urethane) (PU) discs functionalized with a nanocomposite layer containing phloxine B (PhB). Additionally, the effect of PDI on the ALS3 and HWP1 genes of C. albicans was examined in mixed biofilms. Spectral analysis showed a continuous release of PhB from the nanocomposite in Mueller-Hinton broth within 48 h, with a released amount of PhB < 5% of the total amount. The anti-biofilm effectiveness of the light-activated nanocomposite with PhB showed a reduction in the survival rate of biofilm cells to 0.35% and 31.79% for S. aureus and C. albicans, respectively, compared to the control biofilm on PU alone. Scanning electron microscopy images showed that the nanocomposite effectively reduced the colonization and growth of the mixed biofilm. While PDI reduced the regulation of the ALS3 gene, the HWP1 gene was upregulated. Nevertheless, the cell survival of the C. albicans-S. aureus biofilm was significantly reduced, showing great potential for the elimination of mixed biofilms.
Insights
Photodynamic inactivation (PDI) using a phloxine B nanocomposite effectively eliminated mixed biofilms of Candida albicans and Staphylococcus aureus. This innovative approach significantly reduced microbial survival and biofilm growth, offering a promising strategy for combating dangerous infections.
Area of Science:
- Biomaterials Science
- Microbiology
- Photochemistry
Background:
- Opportunistic pathogens *Candida albicans* and *Staphylococcus aureus* cause severe infections.
- Mixed biofilms present a significant clinical challenge due to increased resistance.
- Developing effective strategies to eradicate these biofilms is crucial.
Purpose of the Study:
- To investigate the efficacy of photodynamic inactivation (PDI) against mixed biofilms of *C. albicans* and *S. aureus*.
- To evaluate the performance of poly (urethane) discs functionalized with a phloxine B (PhB) nanocomposite for biofilm elimination.
- To analyze the impact of PDI on specific virulence genes (*ALS3*, *HWP1*) in *C. albicans* within mixed biofilms.
Main Methods:
- Fabrication of poly (urethane) discs with a functionalized nanocomposite layer containing phloxine B.
- Characterization of PhB release kinetics from the nanocomposite.
- Assessment of anti-biofilm effectiveness using PDI on mixed *C. albicans*-*S. aureus* biofilms.
- Microscopic analysis (Scanning Electron Microscopy) of biofilm structure and coverage.
- Gene expression analysis of *ALS3* and *HWP1* in *C. albicans* post-PDI treatment.
Main Results:
- PhB demonstrated sustained release from the nanocomposite (<5% over 48 hours).
- PDI treatment significantly reduced *S. aureus* survival to 0.35% and *C. albicans* survival to 31.79%.
- Scanning Electron Microscopy confirmed reduced biofilm colonization and growth on nanocomposite-treated surfaces.
- PDI downregulated *ALS3* gene expression while upregulating *HWP1* in *C. albicans*.
Conclusions:
- The PhB-functionalized nanocomposite shows high potential for eliminating mixed *C. albicans*-*S. aureus* biofilms via PDI.
- PDI effectively reduces microbial viability and disrupts biofilm architecture.
- Gene expression changes suggest complex regulatory responses to PDI treatment within the biofilm environment.
