Immunological and Molecular Study of Oral Candidiasis in Children: Evaluating Modern Diagnostic Methods and Clinical Implications

Abstract

Oral candidiasis, caused predominantly by Candida albicans, represents one of the most common opportunistic fungal infections in pediatric populations. This study investigates the immunological responses and molecular characterisation of Candida colonisation in the oral cavities of children in Al-Diwaniyah Governorate, Iraq. A cross-sectional study was conducted between January and June 2025 in Al-Diwaniyah Governorate, Iraq. A total of 180 children (aged 2–6 years) were enrolled. All data were analysed using SPSS v26. Chi-square (χ²) test was applied to determine the association between C. albicans colonisation, environmental zone, and ECC status. A p-value < 0.05 was considered statistically significant. Employing a cross-sectional design, 180 children aged 2–6 years were sampled across urban, rural, and agricultural zones. Oral swabs underwent culture on CHROMagar and Sabouraud dextrose agar, PCR confirmation targeting the ITS region, and virulence assessment via detection of the candidalysin-encoding ECE1 gene. Salivary cytokine levels (IL-36, IL-22) were quantified using ELISA. Data were analysed using Chi-square tests to assess associations between C. albicans prevalence, environmental zone, and early childhood caries (ECC) status. We found a significantly higher carriage rate in urban (36.7%) compared to rural (30.0%) and agricultural (18.3%) zones (χ² = 7.89, p = 0.019). ECC-positive children exhibited elevated IL-36 and IL-22 levels (p < 0.01) and a higher frequency of ECE1 detection. These findings underscore the interplay between environment, host immunity, and fungal virulence, offering insights for improved diagnostics and targeted interventions. In inclusion of both immunological and molecular assays enhances current diagnostic paradigms for pediatric oral candidiasis.