Quantitative analysis of association between herpesviruses and bacterial pathogens in periodontitis

Background and Objective: The development of human periodontitis may depend upon cooperative interactions among herpesviruses, specific pathogenic bacteria and tissue-destructive inflammatory mediators. This study sought to identify associations among human cytomegalovirus, Epstein-Barr virus and six putative periodontopathic bacteria in periodontitis lesions. Materials and Methods: Fifteen periodontitis patients (nine with aggressive periodontitis and six with chronic periodontitis) and 15 periodontally normal subjects were included in the study. In each study subject, a microbiological sample was collected, using a curette, from the deepest periodontal probing depth of the dentition. A real-time TaqMan (R) polymerase chain reaction assay was employed to determine the subgingival counts of human cytomegalovirus, Epstein-Barr virus, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Campylobacter rectus. Statistical analysis was performed using the Student's t-test, the Pearson correlation coefficient test and the single variable logistic regression test for odds ratio-based risk calculation. Results: Human cytomegalovirus was detected in eight periodontitis lesions and in one normal periodontal site, Epstein-Barr virus was detected in nine periodontitis lesions and in two normal periodontal sites, and the study bacteria were detected in 6-15 periodontitis lesions and in 1-11 normal periodontal sites. Correlations were found between counts of human cytomegalovirus and Epstein-Barr virus, between counts of human cytomegalovirus and P. gingivalis, T. forsythia and C. rectus, and between counts of Epstein-Barr virus and P. gingivalis and T. forsythia. Human cytomegalovirus and Epstein-Barr virus counts were also positively associated with the level of periodontal attachment loss, probing pocket depth and gingival bleeding on probing. Conclusion: This study confirmed that periodontal human cytomegalovirus and Epstein-Barr virus are associated with major periodontopathic bacteria and with the severity of periodontal disease. The finding of abundant herpesviruses in periodontitis lesions redefines the pathogenic paradigm of the disease. Understanding the interplay between herpesviruses and specific bacterial species in the pathogenesis of periodontitis may form the basis for new approaches to preventing, reducing or delaying tissue breakdown from periodontal infections.