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Updated: Jun 22, 2026
Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells
Published on: December 17, 2015
Quantification of Porphyromonas gingivalis and fimA genotypes in smoker chronic periodontitis
Sílvia R L Teixeira1, Flávia Mattarazo, Magda Feres
1Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil.
Aim:
Porphyromonas gingivalis fimA genotypes were associated with virulence factors in vitro, but little evidence of an association with disease severity were shown in humans. We aimed to correlate levels of P. gingivalis fimA genotypes II and IV and probing depth in smoker-chronic periodontitis subjects.
Material And Methods:
One hundred and sixty eight subgingival samples of 20 smokers non-treated chronic periodontitis subjects obtained from sites with different probing depths [shallow (< or =3 mm), intermediate (4-6 mm), deep (> or =7 mm)] were analysed by real-time PCR for P. gingivalis and genotypes fimA II and IV.
Results:
P. gingivalis and fimA IV were detected in all subjects, whereas fimA II was detected in 18 subjects (90%). One hundred and fifty two sites (90.5%) harboured P. gingivalis. Genotypes II and IV were detected in 28% and 69.6% of sites, respectively. The proportions of genotypes II and IV in relation to P. gingivalis levels were similar in shallow, intermediate and deep probing sites (2.4%, 4.6%, 1.4% for genotype II and 15.5%, 17.7%, 11.7% for genotype IV, respectively), indicating that other non-tested genotypes were more abundant. Increased levels of genotype IV were associated with increasing probing depth, but not of genotype II.
Conclusions:
The data suggested an association between P. gingivalis genotype fimA IV and disease severity in smoker-chronic periodontitis subjects.
Insights
Porphyromonas gingivalis fimA genotype IV is linked to greater disease severity in smokers with chronic periodontitis. This study found genotype IV levels increased with probing depth, unlike genotype II.
Area of Science:
- Periodontology
- Microbiology
- Oral Health
Background:
- Porphyromonas gingivalis fimA genotypes show in vitro virulence but limited human disease association.
- Chronic periodontitis affects smokers, with disease severity varying among individuals.
Purpose of the Study:
- To correlate Porphyromonas gingivalis fimA genotypes II and IV levels with probing depth in smokers with chronic periodontitis.
- To investigate the association between specific P. gingivalis genotypes and periodontal disease severity.
Main Methods:
- Real-time PCR analysis of 168 subgingival samples from 20 untreated smoker chronic periodontitis patients.
- Samples were categorized by probing depth: shallow (≤3 mm), intermediate (4-6 mm), and deep (≥7 mm).
- Quantification of P. gingivalis and its fimA genotypes II and IV.
Main Results:
- P. gingivalis and fimA genotype IV were detected in all subjects; fimA genotype II in 90%.
- Genotype IV levels showed a positive association with increased probing depth.
- Genotype II levels did not correlate with probing depth, suggesting other genotypes are more prevalent.
Conclusions:
- Porphyromonas gingivalis fimA genotype IV is associated with increased disease severity in smokers with chronic periodontitis.
- This finding highlights the potential role of specific P. gingivalis genotypes in periodontal disease progression in this patient group.
