Prevalence of Porphyromonas gingivalis and its relationship with herpesvirus in Indian subjects with chronic periodontitis: A cross-sectional study

Background: Porphyromonas gingivalis (P. gingivalis) is a periodontal pathogen that is commonly harbored in the dental plaque of humans. The aim of this study was to look into the prevalence of P. gingivalis and its association with herpesvirus in Indian subjects. This is probably the first study on the association of this bacterium with herpesvirus in Indians. Materials and Methods: This cross-sectional study consists of 200 subjects, with 100 subjects each in the healthy group and the chronic periodontitis (CP) group. Upon plaque collection, one portion of the samples was immediately plated, on culture media that is selective for P. gingivalis. Total colony-forming units (CFU)/mL from each plate was recorded. The remaining plaque sample was subjected to DNA extraction and polymerase chain reaction (PCR) was performed using specific primers for Cytomegalovirus (CMV) and Epstein–Barr virus (EBV). The data are analyzed using the chi-square test, Spearman's rho correlation coefficient, and Mann–Whitney U test. Results: P. gingivalis was detected in 66% of the subjects with CP and in 40% in the healthy group, and this difference was statistically significant (P = 0.00023). The correlation of clinical parameters with P. gingivalis showed a significant positive correlation, indicating that higher levels of clinical parameters were associated with higher CFUs of P. gingivalis in culture. The comparison of the presence of P. gingivalis between herpesvirus-negative and -positive cases showed that CMV-positive cases had significantly higher levels of this bacterium. Conclusions: The results of this study confirmed the earlier finding of P. gingivalis presence in significantly higher levels in CP subjects and in CMV-positive sites. In addition, there was a positive association of the bacterium with clinical parameters

Culture-based identification of pigmented Porphyromonas and Prevotella species in primary endodontic infections

Background. The most common species isolated from primary endodontic infections are black-pigmented bacteria. These species are implicated in apical abscess formation due to their proteolytic activity and are fastidious in nature. Therefore, the present study was carried out to evaluate the presence and identification of various pigmented Porphyromonas and Prevotella species in the infected root canal through culture-based techniques. Methods. Thirty-one patients with primary endodontic infections were selected. Using sterile paper points, samples were collected from the root canals after access opening and prior to obturation, which were cultured using blood and kanamycin blood agar. Subsequently, biochemical test was used to identify the species and the results were analyzed using percentage comparison analysis, McNemar and chi-squared tests, Wilcoxon match pair test and paired t-test. Results. Out of 31 samples 26 were positive for black-pigmented organisms; the predominantly isolated species were Prevotella followed by Porphyromonas. In Porphyromonas only P. gingivalis was isolated. One of the interesting features was isolation of P. gingivalis through culture, which is otherwise very difficult to isolate through culture. Conclusion. The presence of Prevotella and Porphyromonas species suggests that a significant role is played by these organisms in the pathogenesis of endodontic infections