Frequency of spaP Genetic Determinants in Streptococcus mutans Isolated from Patients with Oral Premalignant Disorders: A Cross-sectional Study

Introduction: The surface-associated Protein (spaP) of Streptococcus mutans is crucial for its virulence, aiding in adherence and biofilm formation. This study explores the prevalence of the spaP gene in clinical strains of S. mutans to understand its potential role in the progression of Oral Premalignant Disorders (OPMD). Aim: To phenotypically characterise S. mutans from clinical samples of patients with OPMD and to assess the frequency of spaP genes in clinical strains of S. mutans. Materials and Methods: This cross-sectional study was conducted at the Department of Microbiology, Saveetha Dental College and Hospitals, Chennai, India, from January 2023 to April 2023. A total of 60 saliva samples were randomly collected from three groups: Group 1 (OPMD, n=20), Group 2 (healthy individuals with dental caries, n=20), and Group 3 (healthy individuals without caries, n=20). The primary inclusion criteria were participants within these three groups, with exclusions for those with systemic diseases, ongoing infections, or recent antibiotic/antifungal use (within the last three months). Saliva samples were cultured on Mutans Sanguis Agar (MSA), and colonies were characterised through Gram staining and catalase testing. Genomic Deoxyribonucleic Acid (DNA) was extracted, and Polymerase Chain Reaction (PCR) was performed to detect the spaP gene. Statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) v25.0, with significance considered at p<0.05. Demographic parameters such as age, sex, and clinical status were analysed. Results: The prevalence of S. mutans was found to be 45% (n=9) in OPMD patients, 40% (n=8) in healthy individuals with caries, and 15% (n=3) in healthy individuals without caries. The frequency of the spaP gene was found to be 88% (n=8) in OPMD patients and 75% (n=6) in healthy individuals with caries. Conclusion: The comparative evaluation of the prevalence of S. mutans and the frequency of the spaP gene among the strains suggests a significant role of the spaP gene in association with both caries and OPMD conditions.