Porphyromonas gingivalis Strain Variability and Periodontitis

Abstract

To determine if there is variability in virulence among strains ofPorphyromonas gingivalis in human periodontitis, their distribution in a group of subjects with clear indicators of periodontitis and in a healthy, age-matched control group was examined. The presence of heteroduplex types of P. gingivalis in the two groups was determined with a PCR-based assay. This assay relied on detection of polymorphisms in the ribosomal internal spacer region (ISR). ISR fragments generated by PCR with P. gingivalis-specific primers were hybridized to fragments from reference strains, and the formation of heteroduplexes from the hybridization of nonidentical sequences was observed by polyacrylamide gel electrophoresis. Characteristic fingerprints from comparison with a panel of reference strains allowed the identification of heteroduplex types in clinical samples. One hundred thirty adults with periodontitis and 181 controls were sampled. With this approach, 11 heteroduplex types of P. gingivalis were detected in the population. Sufficient numbers were available for statistical analysis of six of these types. Heteroduplex type hW83 was found to be very strongly associated with periodontitis (P = 0.0000), and two additional types, h49417 and hHG1691, were also significantly associated with disease. The remaining types, h23A4, h381, and hA7A1, were detected more frequently in subjects with periodontitis than in healthy subjects, but the difference was not significant. These data indicate that virulence in human periodontitis varies among strains ofP. gingivalis, and they identify an apparently highly virulent subgroup.

Quantitative detection ofPorphyromonas gingivalis fimAgenotypes in dental plaque

“…Besides genotype II ¢mbrillin expression, certain heteroduplex types of the ribosomal intergenic spacer region have been linked to human periodontitis [23]. Strains with close relationship to W83^a reference strain for ¢mA genotype IV^were found to be signi¢cantly associated with chronic periodontitis, whereas strains that grouped with A7A1, a marker strain of ¢mA genotype II, showed no disease association because of their frequent presence at healthy sites [23].…”

GM‐CSF and uPA are required for Porphyromonas gingivalis‐induced alveolar bone loss in a mouse periodontitis model

“…This strain was selected for the study as it has been shown to be virulent in murine periodontitis models [90][91][92] and because W50/W83-like strains, based on polymorphisms in the ribosomal internal spacer region, have been closely associated with periodontitis in humans. 93 P. gingivalis W50 was grown and harvested as described previously. [94][95][96] Preparation of heat-killed P. gingivalis W50 (HK-W50) and purification of the RgpA-Kgp proteinase-adhesin complexes (RgpA-Kgp complexes)…”

Strain‐dependent activation of the mouse immune response is correlated with Porphyromonas gingivalis‐induced experimental periodontitis

“…Although the current assumption suggests that a host-dependent exaggerated pro-inflammatory response is the main reason for periodontal destruction, it is possible that different bacterial strains may induce different levels of response. In order to test this possibility, investigators used different strains of P. gingi-valis in various animal models, such as the mouse skin abscess model (Grenier & Mayrand 1987, Ebersole et al 1995b, Griffen et al 1999, the subcutaneous chamber model (Genco et al 1991, Genco & Arko 1994 and the oral infection model (Evans et al 1992, Baker et al 2000. In these studies, many strains of P. gingivalis were classified as either virulent or avirulent; however, the correlation between alveolar bone loss (ABL) and the host immune response following infection with different P. gingivalis strains needs further clarification.…”