Phenotypic species identification and ALS3 gene analysis in Oral <em>Candida albicans</em> isolates in patients with Oral Submucous Fibrosis – A Sri Lankan study

Oral Submucous Fibrosis (OSF) is an Oral Potentially Malignant Disorder, with a substantial risk of malignant transformation. The main risk factors are Areca nut, tobacco, alcohol, and betel quid. While Candida overgrowth is contributing factor, the prevalence of Candida spp. and its virulence genes is not well studied in the Sri Lankan population. The objective of this study was to identify the species level colonization of Candida and the presence of selected virulence genes in OSF patients. A crosssectional study was conducted with 24 OSF patients. Unstimulated whole saliva samples were collected with sociodemographic and risk factor data. Samples were inoculated onto SDA media, resulting cultures were subjected to identification tests, including gram staining, rice plate agar culture, Chrome agar culture and germ tube formation. DNA was isolated from C. albicans positive cultures, and PCR was performed with ALS3 gene primers followed by gel electrophoresis. Data entry and statistical analyses were conducted using Microsoft Office Excel 2023 and SPSS version 25. The mean age of patients was 45±18.24 years, with male: female ratio of 7:1. Candida albicans prevalence was 66.7%; in addition, C. krusei (4.2%) and C. glabrata (4.2%) were identified. Mean CFU/ml in Candida spp. was 491.67±650.179. All 16 isolates of C. albicans were positive for the ALS3 genotype. Statistically no significant associations were reported between Candida spp. prevalence and sex (p=0.546), education (p=0.125), smoking tobacco (p=0.640), and alcohol (p=0.341). No significant association to be found between Candida spp. CFU/ml and smoking tobacco (p=0.283) or alcohol (p=0.880). The pilot data identified different phenotypes of Candida spp. in saliva samples of OSF patients; the most common type was C. albicans. All C. albicans demonstrated the presence of the virulent gene ALS3.