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Published on: September 16, 2022
Characterization of biofilms formed by Candida parapsilosis, C. metapsilosis, and C. orthopsilosis
Ali Abdul Lattif1, Pranab K Mukherjee, Jyotsna Chandra
1Center for Medical Mycology, Department of Dermatology, University Hospital's Case Medical Center, and Case Western Reserve University, 11100 Euclid Ave., Cleveland, OH 44106-502, USA.
Abstract:
Infections due to Candida parapsilosis have been associated with the ability of this fungus to form biofilms on indwelling medical devices. Recently, C. parapsilosis isolates were reclassified into 3 genetically non-identical classes: C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Little information is available regarding the ability of these newly reclassified species to form biofilms on biomedical substrates. In this study, we characterized biofilm formation by 10 clinical isolates each of C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Biofilms were allowed to form on silicone elastomer discs to early (6h) or mature (48 h) phases and quantified by tetrazolium (XTT) and dry weight assays. Surface topography and three-dimensional architecture of the biofilms were visualized using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), respectively. Metabolic activity assay revealed strain-dependent biofilm forming ability of the 3 species tested, while biomass determination revealed that all 3 species formed equivalent biofilms (P>0.05 for all comparisons). SEM analyses of representative isolates of these species showed biofilms with clusters of yeast cells adherent to the catheter surface. Additionally, confocal microscopy analyses showed the presence of cells embedded in biofilms ranging in thickness between 62 and 85 microm. These results demonstrate that similar to C. parapsilosis, the 2 newly identified Candida species (C. orthopsilosis and C. metapsilosis) were able to form biofilms.
Insights
Newly reclassified Candida species, C. orthopsilosis and C. metapsilosis, form biofilms on medical devices, similar to Candida parapsilosis. This research characterizes their biofilm-forming abilities on silicone substrates.
Area of Science:
- Medical Mycology
- Biomedical Engineering
- Infectious Diseases
Background:
- Candida parapsilosis infections are linked to biofilm formation on medical devices.
- Recent reclassification separated C. parapsilosis into three distinct species: C. parapsilosis, C. orthopsilosis, and C. metapsilosis.
- Limited data exists on the biofilm-forming capacity of the newly identified species on biomedical materials.
Purpose of the Study:
- To characterize and compare the biofilm formation capabilities of C. parapsilosis, C. orthopsilosis, and C. metapsilosis.
- To investigate biofilm development on silicone elastomer substrates over early and mature phases.
- To analyze the surface topography and three-dimensional architecture of formed biofilms.
Main Methods:
- Utilized 10 clinical isolates from each of the three Candida species.
- Biofilms were cultured on silicone elastomer discs for 6 hours (early) and 48 hours (mature).
- Quantified biofilm biomass using tetrazolium (XTT) assays and dry weight measurements.
- Visualized biofilm structure and surface topography via scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).
Main Results:
- Metabolic activity assays indicated strain-dependent biofilm formation across the three species.
- Biomass determination showed no significant difference in biofilm formation among the species (P>0.05).
- SEM revealed yeast cell clusters adhering to the catheter surface in biofilms.
- CLSM demonstrated biofilms with thicknesses ranging from 62 to 85 micrometers.
Conclusions:
- C. orthopsilosis and C. metapsilosis, like C. parapsilosis, possess the ability to form biofilms.
- All three species form biofilms on silicone substrates, suggesting potential implications for indwelling medical device-associated infections.
- Further research is warranted to understand the clinical significance of biofilm formation by these distinct Candida species.
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