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Published on: November 5, 2019
Fluorescence of Candida in diagnosis of oral candidiasis
L R Kumaraswamy Naik1, Pushparaja Shetty2, M S Krishna Prasad3
1Department of Dentistry, Belagavi Institute of Medical Sciences, Belagavi, Karnataka, India.
Background:
Many pathogenic fungi fluoresce in hematoxylin and eosin stained sections, and Papanicolaou (PAP)-stained smears under ultraviolet illumination. In theory, this phenomenon could aid in the diagnosis of common fungal infections without the delay which is usually associated with special stains.
Objective:
To evaluate the role of fluorescence as a rapid screening technique for oral infections caused by Candida organisms in exfoliative smears of oral candidiasis.
Materials And Methods:
Two smears and one swab were collected from each of 62 clinically diagnosed cases of oral candidiasis. Smears were stained with (PAP) and periodic acid-Schiff stain (PAS). Both smears were evaluated under light microscopy (LM). Later, PAP smears were observed under fluorescent microscopy (PAP-FM). The swab was inoculated on Sabouraud's agar plate. Each technique was evaluated for sensitivity and specificity.
Results:
It was found that the PAS-stained smears were more reliable for detection of Candida species than other methods (sensitivity = 100%; specificity = 66.7%). The PAP-LM and PAP-FM showed less sensitivity (67.9% and 85.7%) and specificity (66.7% and 33.3%), respectively. Combined results of both light and fluorescent microscopy of PAP (LM + FM) showed increased sensitivity (89.3%) but reduced specificity (16.7%).
Conclusion:
PAP autofluorescence is less sensitive than PAS, still it accentuates the distinct morphological features of Candida.
Insights
Periodic acid-Schiff (PAS) stain is more reliable for detecting Candida infections than Papanicolaou (PAP) staining with or without fluorescence microscopy. While PAP autofluorescence highlights Candida morphology, it is less sensitive for diagnosis.
Area of Science:
- Medical Mycology
- Diagnostic Pathology
- Microscopy Techniques
Background:
- Pathogenic fungi exhibit autofluorescence in H&E and Papanicolaou (PAP)-stained sections under UV light.
- This fluorescence could potentially expedite fungal infection diagnosis, bypassing lengthy special stains.
Purpose of the Study:
- To assess fluorescence as a rapid screening method for oral candidiasis using exfoliative smears.
- To evaluate the diagnostic accuracy of Papanicolaou (PAP)-stained smears with and without fluorescent microscopy for Candida detection.
Main Methods:
- Collected smears and swabs from 62 oral candidiasis cases.
- Stained smears with Papanicolaou (PAP) and Periodic Acid-Schiff (PAS) stains.
- Evaluated smears using light microscopy (LM) and fluorescent microscopy (FM); assessed sensitivity and specificity.
Main Results:
- PAS staining demonstrated 100% sensitivity and 66.7% specificity for Candida detection.
- PAP-LM showed 67.9% sensitivity and 66.7% specificity; PAP-FM showed 85.7% sensitivity and 33.3% specificity.
- Combined PAP (LM + FM) yielded 89.3% sensitivity but only 16.7% specificity.
Conclusions:
- Periodic acid-Schiff (PAS) stain is superior to Papanicolaou (PAP) staining for sensitive Candida detection.
- While Papanicolaou (PAP) autofluorescence is less sensitive, it effectively accentuates Candida's morphological characteristics.
