Frequency of bspA and mutS Genes in Tannerella forsythia Isolated from Patients with Aggressive Periodontitis: A Cross-sectional Study

Introduction: Tannerella forsythia (T. forsythia) is a predominant periodontal pathogen contributing to the progression of periodontitis. Among its virulence factors, the bspA gene, which encodes cysteine protease and the mutS gene, associated with DNA mismatch repair, is considered significant. Aim: To determine the frequency of the bspA and mutS genes in clinical strains of T. forsythia isolated from periodontitis patients and to evaluate their antibiotic resistance profiles. Materials and Methods: This cross-sectional study was conducted at Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, from January 2023 to May 2023, including 45 patients categorised into three groups: Gingivitis (Group I), Periodontitis Stage II (Group II), and Aggressive Periodontitis (Group III). The inclusion criteria were patients aged 18-60 years with periodontal disease, while smokers, pregnant women and those undergoing orthodontic treatment were excluded. Demographic parameters, including age, gender and periodontal health status, were recorded. Subgingival plaque samples were cultured anaerobically to identify T. forsythia, which was confirmed by Polymerase Chain Reaction (PCR). Genomic DNA was extracted for the detection of the bspA and mutS genes. Antibiotic susceptibility was tested using the E-strip method. Data analysis included descriptive statistics, Kruskal-Wallis test and Analysis of Variance (ANOVA) using Statistical Package for the Social Sciences (SPSS) software, with statistical significance set at p-value<0.05. Results: T. forsythia was detected in four out of 15 samples (26.7%) from Group III and in one out of 15 samples (6.7%) from Group II, while no samples from Group I showed its presence. The bspA and mutS genes were detected in three out of four strains (75%) and two out of four strains (50%), respectively. All isolates (100%) demonstrated resistance to metronidazole and clindamycin. Conclusion: This study highlights the prevalence and virulent characteristics of T. forsythia in periodontal diseases, particularly in aggressive periodontitis. The detection of specific virulence genes and the antibiotic resistance patterns observed underscore the pathogenic potential of this bacterium. Regular monitoring of T. forsythia and its antimicrobial susceptibility is crucial for effective periodontal disease management. The findings suggest that targeted treatment strategies, considering the resistance profiles of T. forsythia, are necessary for better clinical outcomes in periodontal care.