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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.

Background: Oral candidiasis continued to receive attention due to its evidenced association with its evidenced association with acquired immunodeficiency syndrome. In spite of considerable improvements in the laboratory diagnostic methods, there is still a need for more reliable, definitive and less time-consuming diagnostic techniques for Candida infection. Many of the studies were done utilizing acridine orange (AO) as a basic fluorescent dye for the demonstration of yeast in cultured Candida species and in histopathological sections. However, only very few studies report this technique to demonstrate Candida organisms in oral smears. The present study was carried out to assess the diagnostic reliability of detection of Candida by utilizing AO fluorescent dye in oral exfoliative smears of oral candidiasis. Materials and Methods: A total of 62 clinically diagnosed cases of oral candidiasis were studied. Two smears and a swab were collected from each suspected lesion. Each slide was stained with, periodic acid Schiff (PAS) reagent and AO. PAS stained smears were then evaluated for the presence of Candida species under light microscopy. AO stained smears were observed under fluorescent microscopy. After inoculation of swab on the saborouds agar plates, the growth of Candida species was evaluated by Gram stain and germ tube test. Each technique was evaluated for sensitivity, specificity, positive predictive value and negative predictive value. Results: It was found that the PAS stained smears were more reliable for detection of Candida species (sensitivity = 100%, specificity = 66.7%), than AO method (sensitivity = 87.5%; specificity = 0%). Conclusion: Acridine Orange fluorescent technique even though rapid lacks specificity for Candida.