Porphyromonas gingivalis, a significant periodontal pathogen, is known to possess genetic variations in relation to its virulence. Furthermore, fimbriae encoded by the fimA gene are involved in bacterial adherence to and invasion of host cells, and a known virulence factor of the bacterium. The fimA gene is classified into six variants (types I-V and Ib) and has been shown to be related to microbial virulence. Polymerase chain reaction (PCR) assay results are helpful to differentiate the genotypes, with fimA type-specific primer sets used for that have been developed by several researchers. Although room for improvement remains, fimA genotyping is expected to become a useful technique for periodontal examinations and diagnosis. In this chapter, currently available PCR methods to classify fimA genotypic variations of P. gingivalis are described.
Keywords: Fimbriae; Genotyping; PCR; Periodontal bacteria; Periodontitis; Polymerase chain reaction; Porphyromonas gingivalis; fimA.