Red/Orange Autofluorescence in Selected Candida Strains Exposed to 405 nm Laser Light
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Published on: March 22, 2024
Rafał Wiench1, Dariusz Paliga2, Anna Mertas3
1Department of Periodontal Diseases and Oral Mucosa Diseases, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland.
Background:
Candida albicans and similar species are significant pathogens in immunocompromised and hospitalized individuals, known for mucosal colonization and bloodstream/organ invasion. Many pathogenic fungi, including these species, exhibit autofluorescence (R/OF) under specific light conditions, a feature crucial for their detection.
Aim:
We investigated the use of a 405 nm diode laser for the direct observation of red/orange autofluorescence of Candida spp., common in the oral cavity, exploring its potential in health screenings.
Methods:
This study utilized cultures of Candida spp. on Sabouraud dextrose agar with Qdot 655 and 685 for fluorescence benchmarking, illuminated using a 405 nm diode laser (continuous wave, power 250 mW, 0.0425 J/cm² fluence, 0.0014 W/cm² power density). Images were captured using a yellow-filter camera at set intervals (48 to 144 h). Visual and computational analyses evaluated the R/OF in terms of presence, intensity, coloration, and intra-colony variation.
Results:
Most Candida strains displayed red/orange autofluorescence at all observation times, characterized by varied coloration and intra-colony distribution. Initially, there was an increase in R/OF intensity, which then stabilized in the later stages of observation.
Conclusions:
The majority of the Candida strains tested are capable of emitting R/OF under 405 nm laser light. This finding opens up new possibilities for integrating R/OF detection into routine dental screenings for Candida spp.
Insights
Most Candida strains exhibit red/orange autofluorescence (R/OF) under 405 nm laser light. This discovery could enable new dental screening methods for Candida spp. detection.
Area of Science:
- Medical Mycology
- Biophotonics
- Diagnostic Microbiology
Background:
- Candida species are significant pathogens, particularly in immunocompromised individuals.
- These fungi can cause mucosal colonization and invasive infections.
- Pathogenic fungi, including Candida, often display red/orange autofluorescence (R/OF), a property useful for detection.
Purpose of the Study:
- To investigate the use of a 405 nm diode laser for observing R/OF in oral Candida species.
- To explore the potential of R/OF detection for health screenings.
Main Methods:
- Cultures of Candida spp. were grown on Sabouraud dextrose agar.
- Qdot 655 and 685 were used for fluorescence benchmarking.
- A 405 nm diode laser illuminated the cultures, and images were captured with a yellow-filter camera.
- Visual and computational analyses assessed R/OF presence, intensity, coloration, and variation.
Main Results:
- The majority of Candida strains demonstrated R/OF under 405 nm laser excitation.
- Autofluorescence varied in coloration and intra-colony distribution.
- R/OF intensity initially increased and then stabilized over time.
Conclusions:
- Most tested Candida strains emit R/OF when exposed to 405 nm laser light.
- This characteristic suggests potential for integrating R/OF detection into routine dental screenings.
- R/OF imaging offers a novel approach for identifying Candida species in oral health settings.
