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Occurrence of Porphyromonas gingivalis fimA type II and prtC genotype among periodontitis patients


Porphyromonas gingivalis fimbriae are classified into six genotypes (types I-V and Ib). Among them, occurrence of fimA type II genotype is more predominant in periodontitis patients. Similarly collagenase encoded by prtC gene is a potential virulence factor expressed by P. gingivalis strains associated with periodontal disease. The study was opted to detect the presence of P. gingivalis fimA type II and prtC genotypes in periodontitis patients.


Subgingival plaque samples collected from 128 chronic periodontitis (ChP) and 72 aggressive periodontitis (AgP) patients were subjected to PCR to screen for the presence of fimA type II and prtC gene of P. gingivalis. Chi-square test was employed to compare the prevalence of the genotypes.


The prevalence of P. gingivalis fimA type II genotype among ChP, AgP and health was 50.5%, 45.3 % and 13.60%, respectively. While, prevalence of P. gingivalis prtC genotype among ChP, AgP and health was 49.5%, 45.3% and 9.10% respectively. P. gingivalis type II fimA+/prtC + genotype were present in 28.9% of ChP, 33.3% of AgP patients and 4.5% of healthy subjects. Patients positive for both the genes showed probing depth of ≥7mm. Significant difference was observed between periodontitis and healthy subjects for all the three genotypes (P=0.001).


The results show that P. gingivalis fimA type II and prtC genotypes are equally associated with chronic and aggressive periodontitis. The predominance of P. gingivalis fimA type II+ / prtC+ genotype in teeth with deep pockets or serious attachment loss, suggest their role in periodontal destruction.

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Correspondence to Mahalakshmi Krishnan.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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About this article


  • Healthy Subject
  • Collagenase
  • Virulence Factor
  • Periodontitis
  • Chronic Periodontitis