Periodontal Disease Bacteria Research Articles

Activation of human gingival epithelial cells by cell-surface components of black-pigmented bacteria: augmentation of production of interleukin-8, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor and expression of intercellular adhesion molecule 1.

Black-pigmented anaerobic bacteria, such as Porphyromonas gingivalis and Prevotella intermedia, are amongst the predominant bacteria in periodontal pockets and have been implicated in periodontal diseases. To elucidate the roles of gingival keratinocytes, which are the first cells encountered by oral bacteria in periodontal diseases, human gingival keratinocytes in primary culture were stimulated with cell-surface components of P gingivalis and Pr. intermedia. A glycoprotein fraction from Pr. intermedia (PGP) clearly augmented the release of interleukin-8, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, as determined by enzyme-linked immunosorbent assay. This PGP also induced expression of intercellular adhesion molecule-1 (ICAM-1), as determined by flow cytometry. The augmentation of mRNA expression for these molecules was also confirmed by reverse transcription PCR. In contrast, lipopolysaccharide (LPS) from Pr. intermedia and Escherichia coli was completely inactive in these assays. LPS fraction and purified fimbriae from P gingivalis exhibited weak activities. Cytokine production and ICAM-1 expression by gingival keratinocytes might cause accumulation and activation of neutrophils in the epithelium and, therefore, may be involved in the initiation and development of inflammation in periodontal tissues.

Role of Anaerobic Bacteria in Periodontal Disease

Microscopic examination and cultural studies of subgingival dental plaque have indicated that a complex, predominantly anaerobic flora is associated with periodontal disease. About 10 to 15 bacterial species, all of them anaerobic with the exception of A actinomycetemcomitans, have been suggested to be periodontal pathogens. These data indicate that most forms of periodontal disease are chronic anaerobic infections. This possibility has been evaluated by the systemic use of metronidazole, an antimicrobial whose spectrum of activity is limited to anaerobes. These six metronidazole double-blind studies demonstrate that metronidazole, given for periods of time as short as 1 week, can lead to a significant improvement in periodontal health. Maximal benefits are obtained when the metronidazole is given after the tooth surfaces are debrided of plaque and calculus. The best response is often noted in the more advanced cases, in which an anaerobic flora including spirochetes and black-pigmented Bacteroides usually predominates in the subgingival plaque. The success of short-term metronidazole treatment in these investigations indicates that the overgrowth of certain anaerobes in the plaque is responsible for most forms of periodontal disease.

Black‐pigmenting Gram‐negative bacteria in periodontal disease. I. Topographic distribution in the human dentition*

The purpose of this study was to determine the distribution of black-pigmenting Gram-negative bacteria in the dentition of periodontitis patients and to examine differences in the microbial composition of samples taken from a series of adjacent sites. Separate subgingival samples were taken from the mesial, buccal, distal and oral aspects of every tooth in 10 subjects. Thus, a total of 927 sites, 84 to 102 per patient, were scored clinically and sampled microbiologically. P. intermedia and P. melaninogenica were found in all subjects. P. gingivalis was found in 7. The organisms tended to be distributed unevenly, giving the impression of clusters of positive samples in certain areas of the dentition. 77% of all samples positive for P. gingivalis were also P. intermedia-positive. Premolars had lower frequencies and mean proportions of P. gingivalis than incisors and molars. In the premolar and molar region, frequencies and mean proportions of P. gingivalis increased with more posterior location. While frequencies indicated a similar topographic distribution of P. intermedia the mean proportions of this organism were more consistent at different locations. Based on a logistic regression model, it was estimated that the probability of detecting P. gingivalis was 34 times higher in any site which had at least 1 P. gingivalis-positive neighboring site. For P. intermedia any site with at least 1 P. intermedia-positive neighboring site had a chance 2.4 times higher of harboring the organism as well. The highest chance of detecting P. gingivalis and P. intermedia existed in deep, oral pockets of molars, which bled upon sampling.

Anaerobes in Periodontal Disease in the Dog: A Review

As anaerobic sampling and culture techniques improved, the documented prevalence of anaerobic bacteria in periodontal disease has increased. The anaerobic bacteria have become more well-known in humans and consequently in dogs, since this species is a major model in periodontal studies. A review of the literature related to anaerobic flora is described.

Accurate DNA probe identification of periodontal disease bacteria

Accurate DNA probe identification of periodontal disease bacteria

Interaction of inflammatory cells and oral microorganisms. VIII. Detection of leukotoxic activity of a plaque-derived gram-negative microorganism

In the present study we identified a gram-negative anaerobic rod referred to as Y4 which was cytotoxic for human polymorphonuclear leukocytes. Y4 was isolated from dental plaque of a patient with juvenile periodontitis and presented most of the taxonomic characteristics of Actinobacillus species. Under experimental conditions, viable Y4 were cytotoxic for human peripheral blood polymorphonuclear leukocytes in serum-free cultures. Cytotoxicity was dependent on bacterial concentrations and was enhanced in the presence of a fresh or heat-inactivated (56 degrees C, 30 min) autologous serum. Leukotoxicity was independent of phagocytosis. Y4 leukotoxic effect was abolished when bacteria were heat treated (56 degrees C, 30 min) or when incubations were carried out at 4 degrees C instead of at 37 degrees C. The leukotoxicity was monitored by electron microscopy and biochemically by measuring lactate dehydrogenase indicator of cell viability. No cytotoxic effects of Y4 on human mononuclear cells, chicken fibroblasts, or mouse macrophages were detected under the conditions studied. Polymorphonuclear leukocytes may play an important role in the host defense against bacteria in periodontal disease. The cytotoxic effect of Y4 for polymorphonuclear leukocytes presented in this study is the first report of a direct offensive microbial vector in a plaque-derived microorganism and may prove to be relevant in the pathogenesis of juvenile periodontitis.

The role of bacteria in periodontal disease

The role of bacteria in periodontal disease