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Published on: September 16, 2022
Candida tropicalis Biofilms: Biomass, Metabolic Activity and Secreted Aspartyl Proteinase Production
Melyssa Negri1,2, Sónia Silva3, Isis Regina Grenier Capoci2
1CEB- Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Abstract:
According to epidemiological data, Candida tropicalis has been related to urinary tract infections and haematological malignancy. Several virulence factors seem to be responsible for C. tropicalis infections, for example: their ability to adhere and to form biofilms onto different indwelling medical devices; their capacity to adhere, invade and damage host human tissues due to enzymes production such as proteinases. The main aim of this work was to study the behaviour of C. tropicalis biofilms of different ages (24-120 h) formed in artificial urine (AU) and their ability to express aspartyl proteinase (SAPT) genes. The reference strain C. tropicalis ATCC 750 and two C. tropicalis isolates from urine were used. Biofilms were evaluated in terms of culturable cells by colony-forming units enumeration; total biofilm biomass was evaluated using the crystal violet staining method; metabolic activity was evaluated by XTT assay; and SAPT gene expression was determined by real-time PCR. All strains of C. tropicalis were able to form biofilms in AU, although with differences between strains. Candida tropicalis biofilms showed a decrease in terms of the number of culturable cells from 48 to 72 h. Generally, SAPT3 was highly expressed. C. tropicalis strains assayed were able to form biofilms in the presence of AU although in a strain- and time-dependent way, and SAPT genes are expressed during C. tropicalis biofilm formation.
Insights
Candida tropicalis forms biofilms in artificial urine, with gene expression varying by strain and time. Biofilm cell counts decrease after 48-72 hours, while SAPT3 shows high expression.
Area of Science:
- Mycology
- Medical Microbiology
- Molecular Biology
Background:
- Candida tropicalis is linked to urinary tract infections and malignancy.
- Biofilm formation and proteinase production are key virulence factors for C. tropicalis.
- Understanding C. tropicalis biofilm behavior in urine is crucial for infection control.
Purpose of the Study:
- To investigate the behavior of Candida tropicalis biofilms of varying ages (24-120 hours) in artificial urine.
- To analyze the expression of aspartyl proteinase (SAPT) genes during C. tropicalis biofilm formation in artificial urine.
Main Methods:
- Culturable cell enumeration (CFU), crystal violet staining for biomass, and XTT assay for metabolic activity were used to evaluate biofilms.
- Real-time PCR was employed to determine SAPT gene expression.
- Experiments utilized a reference strain (C. tropicalis ATCC 750) and two clinical isolates from urine.
Main Results:
- All tested C. tropicalis strains formed biofilms in artificial urine, with strain- and time-dependent variations.
- A decrease in culturable cells was observed between 48 and 72 hours of biofilm formation.
- SAPT3 gene expression was generally high, and SAPT genes were expressed throughout biofilm development.
Conclusions:
- Candida tropicalis can form biofilms in artificial urine, demonstrating strain-specific and temporal characteristics.
- SAPT gene expression, particularly SAPT3, is a significant feature during C. tropicalis biofilm formation in urine.
- These findings provide insights into the pathogenesis of C. tropicalis urinary tract infections.
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