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Red/Orange Autofluorescence in Selected Candida Strains Exposed to 405 nm Laser Light
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.
