The characteristics of a group of slow-growing, fusiform, fastidious anaerobes isolated from advanced periodontal lesions in human oral cavities were examined. Our results indicated that 12 fusiform Bacteroides strains belong to a new species in the genus Bacteroides. The name Bacteroides forsythus is proposed for these isolates. The type strain is strain ATCC 43037.Anaerobic, gram-negative, fusiform organisms which did not resemble previously recognized speqies were isolated from deep periodontal pockets of humans that showed progressive tissue loss (3,15,17). The cells appeared to be long filaments or medium rods with tapered (fusiform) or rounded ends. Some cells had central swellings. Large spheroids were frequently associated with the cells, particularly the cells with filamentous morphology. These strictly anaerobic fusiform Bacteroides strains grew slowly on blood agar plates and grew poorly in all broth media tested and on most agar media tested. Biochemical tests gave inconsistent results and were usually negative. For this reason, the fusiform Bacteroides strains were characterized without using most of the conventional biochemical tests, Deoxyribonucleic acid (DNA) guanine-plus-cytosine (G +C) content, DNA-DNA homology, cell wall ultrastructure, serology, API enzyme substrate tests (Analytab Products, Plainview, N.Y.), and protein profiles of whole sonicated cells obtained by using polyacrylamide gel electrophoresis (PAGE) indicated that these organisms comprise a distinct species in the genus Bacteroides. The name Bacteroides forsythus is proposed for this new species.Strains and inocula. The strains which we used are listed in Table 1. These organisms were maintained on Trypticase soy agar plates supplemented with 5% sheep blood (TSBA; BBL Microbiology Systems, Cockeysville, Md.) at 35 to 37°C in an atmosphere containing 10% H2, 10% CO2, and 80% N2. The fusiform Bacteroides strains were maintained on TSBA plates; a fusiform Bacteroides strain was streaked on one-half of each plate, and a strain of Fusobacterium nucleaturn was streaked on the other half of the plate. The strains were stored in liquid nitrogen by using previously described methods (14). Inocula for tests were obtained by scraping cells from the surfaces of TSBA plates. At least 100 plates of fusiform Bacteroides strains were used to obtain sufficient cells for DNA extraction. Two to four plates were used to provide the inoculum for an enzyme-linked immunosorbent assay and for each of the tests in the API enzyme substrate test series.DNA-DNA hybridization. Cells of reference strains were grown in 2-to 3-liter broth cultures (mycoplasma broth [BBL] supplemented with 5 mg of hemin per liter) for extraction of DNA. The DNA was extracted by using a method modified (13) from the procedure of Marmur (9). G+C contents were determined by the thermal denaturation method (1). Levels of DNA-DNA homology were determined by using the initial renaturation rates (2).API enzyme substrate tests. API ZYM and API An-Ident enzymatic substrate tests were ...

We report radiographic, clinical, historical, and laboratory observations on seven patients selected to illustrate the features and characteristics of rapidly progressive periodontitis, with the aim of establishing this disease as a distinct clinical entity. This form of periodontitis is seen most commonly in young adults in their twenties, but it can occur in postpubertal individuals up to approximately 35 years of age. During the active phase, the gingival tissues are extremely inflamed and there is hemorrhage, proliferation of the marginal gingiva, and exudation. Destruction is very rapid, with loss of much of the alveolar bone occurring within a few weeks or months. This phase may be accompanied by general malaise, weight loss, and depression, although these symptoms are not seen in all patients. The disease may progress, without remission, to tooth loss, or alternatively, it may subside and become quiescent with or without therapy. The quiescent phase is characterized by the presence of clinically normal gingiva that may be tightly adapted to the roots of teeth with very advanced bone loss and deep periodontal pockets. The quiescent phase may be permanent, it may persist for an indefinite period, or the disease activity may return. Most patients with rapidly progressive periodontitis have serum antibodies specific for various species of Bacteroides, Actinobacillus, or both, and manifest defects in either neutrophil or monocyte chemotaxis. Affected patients generally respond favorably to treatment by scaling and open or closed curettage, especially when accompanied by standard doses of antibiotics for conventional time periods. A small minority of patients do not respond to any treatment, including antibiotics, and the disease progresses inexorably to tooth loss even in the presence of aggressive periodontal therapy and maintenance. At the present time it is not possible to distinguish prior to treatment which individuals will respond to therapy and which will not.

Gingival inflammation and alveolar bone resorption are hallmarks of adult periodontitis, elicited in response to oral micro-organisms such as Porphyromonas gingivalis. We hypothesized that omega (ω)-3 fatty acids (FA) dietary supplementation would modulate inflammatory reactions leading to periodontal disease in infected rats. Rats were fed fish oil (ω-3 FA) or corn oil (n-6 FA) diets for 22 weeks and were infected with P. gingivalis. Rats on the ω-3 FA diet exhibited elevated serum levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), documenting diet-induced changes. PCR analyses demonstrated that rats were orally colonized by P. gingivalis; increased IgG antibody levels substantiated this infection. P. gingivalis-infected rats treated with ω-3 FA had significantly less alveolar bone resorption. These results demonstrated the effectiveness of an ω-3 FA-supplemented diet in modulating alveolar bone resorption following P. gingivalis infection, and supported that ω-3 FA may be a useful adjunct in the treatment of periodontal disease. Abbreviations: PUFA, polyunsaturated fatty acid; EPA, eicosapentanoic acid; DHA, docosahexanoic acid; and PCR, polymerase chain-reaction.

Objective This study is to assess the antibacterial activity of omega-6, -7, -9 (n-6, n-7, n-9) fatty acids against various oral microorganisms. Methods The n-6, n-7, n-9 fatty acids, such as γ-linoleic acid (GLA), linoleic acid (LA), arachidonic acid (ARA), palmitoleic acid (PA), and oleic acid (OA), their fatty acid ethyl esters, GLA-EE, LA-EE, ARA-EE, PA-EE, OA-EE, and their fatty acid methyl esters, GLA-ME, LA-ME, ARA-ME, PA-ME, OA-ME were investigated for antimicrobial activity against oral pathogens Streptococcus mutans, Candida albicans, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis. Various concentrations of the fatty acids, their methyl and ethyl esters were tested against various oral pathogens in 96-well plates and blood-agar plate. The plates were incubated anaerobically or aerobically at 37°C for 48 hours, and the colony forming units (CFU) were determined. Results The data demonstrated that select n-6, n-7, n-9 fatty acids and their esters exhibited strong antimicrobial activity against these oral microorganisms, demonstrating some specificity for individual microbial species. Conclusion The potential use or the combinations of the n-6, n-7, n-9 fatty acids and/or their esters, provided in a local delivery vehicle to infected sites in the oral cavity, could be considered as an additional therapeutic approach to improving oral health.