Detection of Virulent Genotypes FimA II and FimAIV of Porphyromonas gingivalis in Periodontitis Patients Attending the Dental Teaching Hospital, Peradeniya

Porphyromonas gingivalis is the major bacterium involved in the pathogenesis of periodontitis. This disease is prevalent in more than 90% of Sri Lankan adults. Severe periodontitis can lead to loss of teeth and is also implicated in a myriad of health complications, including cardiovascular diseases, stroke, arthritis and oral cancer. Fimbriae is a key virulent factor of P. gingivalis. Based on the diversity of the FimA gene, which encodes a subunit of its fimbriae, P. gingivalis is classified into several genotypes. According to the studies conducted in other countries, FimA II and FimA IV genotypes have been strongly associated with periodontitis. However, FimA genotypic diversity of P. gingivalis in the Sri Lankan population has not been studied. Therefore, this study aimed to identify the FimA II and FimA IV genotypes of P. gingivalis from the saliva of periodontitis patients visiting the Peradeniya University Dental Hospital. DNA was extracted from their saliva samples and analyzed for the presence of P. gingivalis using species-specific primers. Thirty-four samples positive for P. gingivalis were subsequently analyzed by PCR using FimA II and FimA IV genes-specific primers. PCR amplicons were subjected to agarose gel electrophoresis and visualized by a gel imaging system. Among the P. gingivalis positive saliva samples, 73.5% (25/34) harbored the FimA II genotype, while 20.6% (7/34) harbored the FimA IV genotype. Notably, both genotypes were observed in 8.8% (3/34) of samples. However, 14.7% (5/34) of samples were negative for both genotypes. In conclusion, FimA II is the predominant genotype of P. gingivalis associated with periodontitis in our study population. This is the first insight into the virulent genotypes of P. gingivalis in the Sri Lankan population. This finding may be utilized in population screening for risk assessment of periodontitis and developing targeted therapeutics against FimA II expression enabling effective management of periodontitis in Sri Lankans.