Resumen de Detection of Eight Periodontal Microorganisms and Distribution of Porphyromonas gingivalis fimA Genotypes in Chinese Patients With Aggressive Periodontitis
Background: The microbiologic feature of aggressive periodontitis (AgP) in Chinese patients has not yet been determined. This study aims to investigate the prevalence of eight periodontal microorganisms and the distribution of the Porphyromonas gingivalis fimA genotype in a cohort of Chinese patients with AgP.
Methods: Saliva and pooled subgingival plaque samples were collected from 81 patients with AgP (25 with incisor�first molar type and 56 with generalized type [GAgP]) and 34 periodontally healthy controls. Eight periodontal microorganisms, including Aggregatibacter actinomycetemcomitans, P. gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter rectus, Prevotella intermedia, Prevotella nigrescens, and Fusobacterium nucleatum were detected in these samples by the polymerase chain reaction (PCR). In addition, the distribution of fimA genotypes was assessed in P. gingivalis�positive individuals by PCR.
Results: The prevalence of P. gingivalis, T. forsythia, T. denticola, C. rectus, P. intermedia, F. nucleatum, and A. actinomycetemcomitans in patients with AgP was significantly higher than that in healthy controls. The prevalence of A. actinomycetemcomitans in patients with GAgP was relatively low (30.4%) compared with other pathogens. Results of logistic regression analysis showed that younger patients were more likely to harbor A. actinomycetemcomitans (odds ratio = 2.85). Type II was the most prevalent fimA genotype of P. gingivalis in patients with AgP.
Conclusions: P. gingivalis, T. forsythia, T. denticola, C. rectus, P. intermedia, and F. nucleatum were the predominant periodontal pathogens of patients with GAgP in China. Type II of fimA was the most prevalent genotype of P. gingivalis in patients with AgP. The prevalence of A. actinomycetemcomitans in patients with GAgP was relatively low.
Aggressive periodontitis (AgP) is an uncommon form of periodontal disease characterized by early onset and rapid progression.1 Periodontitis is caused by an overgrowth of putative periodontal microorganisms in subgingival plaque followed by an immunoinflammatory response in a susceptible host. Aggregatibacter actinomycetemcomitans has long been considered as a major etiologic agent of patients with AgP,2-4 especially in patients with localized AgP (LAgP).5,6 However, the prevalence of periodontal microorganisms may differ among racial populations.7,8 A study from China in 1991 did not detect A. actinomycetemcomitans in any subgingival plaque samples from 15 juvenile patients with periodontitis,9 and similar results were obtained in studies from Japan,10 the United Kingdom,11 Chile,12 and Colombia.13 Besides race, a number of other factors have been considered to play important roles in governing the microbial composition of plaque samples from a particular individual. These factors include the following: 1) number or type of sampling sites;14 2) age;15 3) local clinical status of sampling sites (probing depth [PD], bleeding index [BI], etc.); 5,15 and 4) environmental factors, such as smoking status.11,16 Other periodontopathic bacteria, such as Porphyromonas gingivalis, are also suspected of participating in patients with AgP of certain populations.5,10 P. gingivalis has been shown to produce a number of virulence factors, including fimbriae, lipopolysaccharide, capsule, and protease.17 Among them, fimbriae was recognized as a critical virulence factor influencing disease initiation and progression, because it was thought to play an important role in the colonization and invasion of periodontal tissues.18 The fimA gene, encoding fimbrillin (a subunit protein of fimbriae), has been classified into six genotypes based on the nucleotide sequences (types I, Ib, II, III, IV, and V).19 Results of several studies showed that different P. gingivalis fimA genotypes had significant virulence diversity.20,21 Most patients with chronic periodontitis (CP) were found to harbor P. gingivalis fimA genotype II, followed by type IV.19,22,23 In contrast, type I was the most prevalent genotype in healthy adults.22,24 However, some studies have focused on the distribution of P. gingivalis fimA genotype in patients with AgP. Thus, it is important to know the distribution of the P. gingivalis fimA genotype in patients with AgP and to further understand the etiology of AgP.
The present study aims to investigate the prevalence of eight major periodontal microorganisms and the distribution of the P. gingivalis fimA genotype in saliva and subgingival plaque of Chinese patients with AgP compared with periodontally healthy young controls.
