Beta-hemolytic streptococci in advanced periodontitis

Aggressive periodontitis in southwestern American Indian adolescents

BACKGROUND

This study determined the prevalence of aggressive (molar-incisor pattern) (Ag/MI) periodontitis and assessed the associated subgingival bacterial-herpesvirus microbiota in Pueblo Indian adolescents in the southwestern United States.

METHODS

The study included 240 Pueblo Indian adolescents, aged 13-20 years old, residing in three Rio Grande River villages in New Mexico and the Hopi Pueblo reservation in Arizona. Adolescents with Ag/MI periodontitis or periodontal health provided subgingival samples for culture of bacterial pathogens and for polymerase chain reaction detection of periodontal herpesviruses.

RESULTS

Ag/MI periodontitis was detected in 22 (9.2%) Pueblo Indian adolescents, with 21 exhibiting a localized molar-incisor breakdown pattern. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and other red/orange complex bacterial pathogens predominated in Ag/MI periodontitis, whereas periodontal health yielded mainly viridans streptococci and Actinomyces species. Periodontal herpesviruses demonstrated a 3.5 odds ratio relationship with Ag/MI periodontitis. The only adolescent with generalized Ag/MI periodontitis harbored viral co-infection by cytomegalovirus plus Epstein-Barr virus Type 1, in addition to A. actinomycetemcomitans, P. gingivalis, and several other periodontopathic bacteria.

CONCLUSIONS

Pueblo Indian adolescents showed an unusually high prevalence of early-age Ag/MI periodontitis predominated by periodontopathic bacteria and herpesviruses suspected to be major etiologic agents of the disease.

Association of clinical parameters with periodontal bacterial haemolytic activity

AIMS

To determine whether haemolytic activity of subgingival bacteria is associated with periodontitis clinical parameters and to identify which bacteria produce the haemolysins.

MATERIALS AND METHODS

Subgingival plaque samples from 22 untreated chronic periodontitis patients were investigated by culture and identified with matrix assisted laser desorption/ionisation time-of-flight mass spectrometry.

RESULTS

Total aerobic and anaerobic bacterial viable counts, percentage distribution of α- and β-haemolytic bacteria were significantly elevated in diseased sites in relation to healthy sites (p < 0.001). Periodontal pathogens were more frequently detected at diseased sites: Porphyromonas gingivalis, Tannerella forsythia, Treponema sp., Prevotella sp., Parvimonas micra, Fusobacterium sp., Campylobacter sp., Capnocytophaga sp., and Selenomonas sp. Haemolytic unidentifiable species and Gram-positive anaerobes such as Slackia exigua, Solobacterium moorei, and Bulledia extructa were also more frequently detected at diseased sites. In diseased sites, the presence of different haemolytic characteristics was more strongly correlated with clinical measures of disease than the mere absence or presence of specific species. The strongest correlation with probing pocket depth was observed for overall β-haemolytic toxicity (r = 0.73, p < 0.001).

CONCLUSION

A strong association was observed between subgingival bacterial haemolytic activity and clinical parameters in patients with chronic periodontitis. Further investigations are warranted to delineate the role of haemolysins in the pathogenesis of periodontitis.

Low-cost periodontal therapy

Periodontitis is a complex infectious disease that affects low-income individuals disproportionately. Periodontitis is associated with specific bacterial species and herpesviruses, and successful prevention and treatment of the disease is contingent upon effective control of these pathogens. This article presents an efficacious, highly safe, minimally invasive, practical and low-cost periodontal therapy that involves professional and patient-administered mechanical therapy and antimicrobial agents. The major components are scaling for calculus removal, periodontal pocket irrigation with potent antiseptics, and treatment with systemic antibiotics for advanced disease. Povidone-iodine and sodium hypochlorite have all the characteristics for becoming the first-choice antiseptics in the management of periodontal diseases. Both agents show excellent antibacterial and antiviral properties, are readily available throughout the world, have been safely used in periodontal therapy for decades, offer significant benefits for individuals with very limited financial resources, and are well accepted by most dental professionals and patients. Four per cent chlorhexidine applied with a toothbrush to the most posterior part to the tongue dorsum can markedly reduce or eliminate halitosis in most individuals. Systemic antibiotics are used to treat periodontopathic bacteria that are not readily reached by topical therapy, such as pathogens within gingival tissue, within furcation defects, at the base of periodontal pockets, and on the tongue, tonsils and buccal mucosae. Valuable antibiotic therapies are amoxicillin-metronidazole (250 mg of amoxicillin and 250 mg of metronidazole, three times daily for 8 days) for young and middle-aged patients, and ciprofloxacin-metronidazole (500 mg of each, twice daily for 8 days) for elderly patients and for patients in developing countries who frequently harbor enteric rods subgingivally. Scaling to remove dental calculus and the prudent use of inexpensive antimicrobial agents can significantly retard or arrest progressive periodontitis in the great majority of patients.

Opportunistic microorganisms in patients undergoing antibiotic therapy for pulmonary tuberculosis

Antimicrobial therapy may cause changes in the resident oral microbiota, with the increase of opportunistic pathogens. The aim of this study was to compare the prevalence of Candida, Staphylococcus, Pseudomonas and Enterobacteriaceae in the oral cavity of fifty patients undergoing antibiotic therapy for pulmonary tuberculosis and systemically healthy controls. Oral rinsing and subgingival samples were obtained, plated in Sabouraud dextrose agar with chloramphenicol, mannitol agar and MacConkey agar, and incubated for 48 h at 37°C. Candida spp. and coagulase-positive staphylococci were identified by phenotypic tests, C. dubliniensis, by multiplex PCR, and coagulase-negative staphylococci, Enterobacteriaceae and Pseudomonas spp., by the API systems. The number of Candida spp. was significantly higher in tuberculosis patients, and C. albicans was the most prevalent specie. No significant differences in the prevalence of other microorganisms were observed. In conclusion, the antimicrobial therapy for pulmonary tuberculosis induced significant increase only in the amounts of Candida spp.

Evaluation of subgingival bacterial plaque changes and effects on periodontal tissues in patients with renal transplants under immunosuppressive therapy

OBJECTIVE

The purpose of this study was to identify the presence of periodontal microrganisms in 35 renal transplant patients before the transplant procedure.

STUDY DESIGN

At each time point, clinical parameters were recorded and subgingival plaque samples were collected from 4 different sites at days 30 and 90 after surgery. Samples were plated onto selective and nonselective media to determine total colony counts and the presence of putative periodontal pathogens. After transplant surgery, patients received immunosuppressive therapy.

RESULTS

Statistical analysis of the microbiologic data showed significant changes between time points. An increase in total counts of microrganisms was observed on day 90 after surgery. As a side effect of cyclosporine, 14 patients developed gingival overgrowth. Beta-hemolytic Streptococcus was more frequently detected in patients who did not present gingival overgrowth 90 days after surgery.

CONCLUSION

Quantitative and qualitative changes of the subgingival microflora can occur 90 days after transplant surgery, while patients are still under immunosupressive drugs.

[Bacteroides forsythus: sensitivity to antimicrobial agents in samples from patients with periodontitis]

An in vitro antimicrobial sensitivity test (technique of agar dilution) was carried out for 105 clinical isolates of B. forsythus from patients with periodontitis. Metronidazole and amoxicillin were the most efficient drugs and, thus, are indicated for the treatment of periodontal infections in which this microorganism is the most prevalent pathogen.

beta-Hemolytic streptococci and other beta-hemolytic organisms in apical periodontitis and severe marginal periodontitis

Thirteen teeth with necrotic pulps and apical periodontitis and nine severe periodontal pockets were cultured for presence of beta-hemolytic streptococci and other beta-hemolytic organisms. Samples were dispersed and plated on two non-selective and one selective growth media and incubated anaerobically and in 10% CO2 in air. A total of 59 beta-hemolytic colonies were purified and identified. Eight beta-hemolytic streptococcal isolates were obtained from three of the severe marginal periodontitis sites. All were identified as belonging to the Streptococcus sanguis group. No beta-hemolytic streptococci were detected in apical periodontitis samples. Twenty obligately anaerobic isolates were detected, all of which were known periodontal and endodontic pathogens. Isolates from apical periodontitis sites were identified as Propionibacterium acnes, Actinomyces naeslundii, Actionomyces odontolyticus and Peptostreptococcus micros, while severe marginal periodontal sites contained the same species with the addition of Actinomyces viscosus and Actinomyces meyeri. Of 19 staphylococci and micrococci, Staphylococcus epidermidis was the predominant isolate in both apical periodontitis and severe marginal periodontitis sites. However, less commonly known organisms such as Staphylococcus cohnii and Micrococcus sp. were identified in severe marginal periodontitis sites. The isolation of Bacillus sp. (12 isolates) in one severe marginal periodontitis and two apical periodontitis subjects was especially interesting, warranting consideration of this organism as a legitimate isolate and potential pathogen in oral disease.

Interactions between non-immune host cells and the immune system during periodontal disease: role of the gingival keratinocyte

Periodontal disease and inflammatory dermatoses, such as psoriasis, are characterized by the accumulation of dense inflammatory infiltrates immediately beneath the epithelial cell layer of the gingiva and skin, respectively. Dermatologists are increasingly aware that the epidermal keratinocyte probably contributes to inflammatory disease progression by secreting a number of pro-inflammatory cytokines and expressing various adhesion molecules. In psoriatic lesions, it is now believed that epidermal keratinocytes may also act as antigen-presenting cells and participate directly in the superantigenic activation of T-cell clones, some of which may initiate, contribute to, or maintain the disease process. Although the role of the host response in periodontal disease has been extensively studied over the years, very little is known about the contribution of the gingival keratinocyte to the inflammatory response. The available published information is discussed in this review, and we suggest that, like its epidermal counterpart, the gingival keratinocyte may participate actively in the pathogenesis of periodontal disease.

Antigen-presenting properties of gingival fibroblasts in chronic adult periodontitis

Chronic periodontitis is characterized by dense infiltrations of T lymphocytes in the connective tissue, which consists mainly of gingival fibroblasts. It is becoming increasingly clear that T lymphocytes and gingival fibroblasts are capable of influencing each other. For example, the T cell cytokine interferon-gamma (IFN-gamma) is able to induce MHC class II molecules on the surface of several cell types, including gingival fibroblasts. Histological sections of chronically inflamed gingival tissue showed a great number of CD4+ and CD8+ T cells that produced IFN-gamma, and in addition showed abundant expression of MHC class II molecules on gingival fibroblasts. Therefore, we investigated whether these gingival fibroblasts acquire the capacity to carry out MHC class II-restricted functions such as antigen presentation to local T cells. In this study, we show that IFN-gamma-treated gingival fibroblasts were able to function as antigen-presenting cells (APC) for superantigen-mediated T cell proliferation. However, these fibroblasts failed to present whole-cell antigens of periodontitis-associated bacteria. Moreover, gingival fibroblasts inhibited the presentation of the whole-cell antigens of these bacteria by professional APC. This inhibition could be overcome by the addition of IL-2. These results suggest that gingival fibroblasts play an important role in the local specific immune response in chronic inflammatory periodontal lesions by regulating the response of infiltrating T cells.

Utility of 5 major putative periodontal pathogens and selected clinical parameters to predict periodontal breakdown in patients on maintenance care

The predictive utility of 5 major putative periodontopathic microbial species, "superinfecting" organisms, and several clinical periodontal parameters were assessed relative to periodontitis recurrence over a 12-month period in 78 treated adult patients participating in a 3-month maintenance care program. At baseline, pooled subgingival microbial samples were collected from each patient, and whole-mouth evaluations of probing depth, relative periodontal attachment level, furcation involvement, and indices of plaque and gingival inflammation were carried out. 67 (85.9%) subjects were culture-positive at baseline for presence of either Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Campylobacter rectus or Peptostreptococcus micros, with 48 (61.5%) subjects yielding one or more of these species at or above designated threshold proportions of > or = 0.01% for A. actinomycetemcomitans, > or = 0.1% for P. gingivalis, > or = 2.5% for P. intermedia, > or = 2.0% for C. rectus, and > or = 3.0% for P. micros. Subgingival yeasts were recovered from 12 subjects, staphylococci from 7, and enteric rods/pseudomonads from 6; however, no subjects revealed > or = 1.0% baseline proportions of these "superinfecting" organisms in subgingival specimens. Periodontitis recurrence in subjects was defined as any periodontal site exhibiting either a probing depth increase of > or = 3 mm from baseline, or a probing depth increase of > or = 2 mm from baseline together with a loss in relative periodontal attachment of > or = 2 mm from baseline. 15 (19.2%) study subjects showed periodontitis recurrence within 6 months of baseline, and 25 (32.1%) within 12 months. The mere baseline presence of the 5 major test species and "superinfecting" organisms were not significant predictors of periodontitis recurrence over 12 months. However, a 2.5 relative risk for periodontitis recurrence over 12 months was found for subjects yielding one or more of the 5 major test species at or above the designated baseline threshold proportions (p = 0.022, Mantel-Haenszel chi 2 test). The positive predictive value for periodontitis recurrence of a microbiologic analysis encompassing the 5 major test species at or above the designated threshold proportions improved with increasing time from baseline, up to approximately 42% at 12 months. Baseline variables jointly providing in multiple regression analysis the best predictive capability for periodontitis recurrence in subjects over a 12-month period were recovery of one or more of the 5 major test species at or above designated threshold proportions, the proportion of sites per subject with > or = 5 mm probing depth, and the mean whole-mouth probing depth. These findings indicate that one or more of 5 major putative periodontal pathogens in elevated subgingival proportions together with increased probing depth predispose adults on maintenance care to recurrent periodontitis.

Evidence for involvement of superantigens in human periodontal diseases: skewed expression of T cell receptor variable regions by gingival T cells

Immunomodulation by periodontopathic bacteria has been implicated in the pathogenesis of inflammatory periodontal diseases. A novel class of microbial-derived T cell mitogens, referred to as superantigens, has recently been described. Superantigens are unique in that they induce a tremendous activation and expansion of specific subsets of T cells in an antigen-independent manner, thereby causing immune dysfunction. Subsets of superantigen-expanded T cells can be identified with reagents that discriminate among different families of the variable domains of the T cell antigen receptor beta-chain (V beta). Since superantigens expand one or a few of these T cell antigen receptor V beta families, T cell subsets that have been expanded by superantigens have restricted expression of one or a few V beta families. In the present study, we investigated the presence of putative superantigen-stimulated T cells in periodontitis sites, utilizing a panel monoclonal antibodies to T cell antigen receptor V beta families. Leukocytes were isolated from gingival tissues obtained from 8 periodontitis and 4 non-periodontitis patients by collagenase digestion. Three-color flow cytometric analysis of these gingival cells demonstrated that in most periodontitis patients examined, patterns of V beta expression among T cells are characteristic of superantigen stimulation, i.e., there is an elevation in the proportion of one or a few V beta families. Specifically, these analyses revealed that T cell subsets expressing V beta 5a and V beta 5b, V beta 6, V beta 8 and V beta 12 were each elevated greater than 2 standard deviations in at least one periodontitis patient compared with the mean of the non-periodontitis subjects. In some periodontitis patients, a less marked elevation of T cells that express V beta 3, V beta 5a, V beta 5b, V beta 6, V beta 8, V beta 12, and V beta 13 was noted (greater than 1 standard deviation higher than the mean of the V beta families in non-periodontics subjects). Interestingly, V beta 8+ T cells were elevated to some degree in all periodontitis patients examined. In contrast, T cells expressing V beta 2, V beta 17 and V beta 19 were not significantly different in any of the subjects studied. In most periodontitis but not non-periodontitis patients, up to 50% of all gingival T cells expressed one or a few T cell antigen receptor V beta families, suggesting that superantigens constitute a major pathway of T cell activation and expansion. Hence, our data support the hypothesis that a large proportion of T cells in periodontitis sites have been stimulated and expanded by superantigens, presumably produced by periodontitis-associated bacteria.

Revised sequence of the Porphyromonas gingivalis prtT cysteine protease/hemagglutinin gene: homology with streptococcal pyrogenic exotoxin B/streptococcal proteinase

The prtT gene from Porphyromonas gingivalis ATCC 53977 was previously isolated from an Escherichia coli clone possessing trypsinlike protease activity upstream of a region encoding hemagglutinin activity (J. Otogoto and H. Kuramitsu, Infect. Immun. 61;117-123, 1993). Subsequent molecular analysis of this gene has revealed that the PrtT protein is larger than originally reported, encompassing the hemagglutination region. Results of primer extension experiments indicate that the translation start site was originally misidentified. An alternate open reading frame of nearly 2.7 kb, which encodes a protein in the size range of 96 to 99 kDa, was identified. In vitro transcription-translation experiments confirm this size, and Northern (RNA) blot experiments indicate that the protease is translated from a 3.3-kb mRNA. Searching the EMBL protein database revealed that the amino acid sequence of the revised PrtT is similar to sequences of two related proteins from Streptococcus pyogenes. PrtT is 31% identical and 73% similar over 401 amino acids to streptococcal pyrogenic exotoxin B. In addition, it is 36% identical and 74% similar over 244 amino acids with streptococcal proteinase, which is closely related to streptococcal pyrogenic exotoxin B. The similarity is particularly high at the putative active site of streptococcal proteinase, which is similar to the active sites of the family of cysteine proteases. Thus, we conclude that PrtT is a 96- to 99-kDa cysteine protease and hemagglutinin with significant similarity to streptococcal enzymes.

Mitsuokella dentalis in human periodontitis

The occurrence of Mitsuokella dentalis in periodontitis was determined by culture and DNA probe detection. Subgingival paper-point samples from 480 periodontitis patients were transported in VMGA III, plated onto brucella agar with 5% sheep blood and incubated anaerobically for 7 days. Presumptive identification was based on a colony morphology resembling a water drop and biochemical characteristics. DNA probe detection was performed on paper-point samples using a digoxigenin-labeled cellular M. dentalis DNA probe in a dot-blot assay. Culture and DNA probe identified M. dentalis in 18.1% and in 80.7% of the study patients, respectively. M. dentalis isolates produced phosphatases, galactosidase, glucosidase and acetylglucosaminidase and showed high in vitro sensitivity to metronidazole. This study revealed that M. dentalis is a constituent of the pathogenic microbiota in human periodontitis. The periodontopathic potential of the organism is unknown.

Microorganisms in polytetrafluoroethylene barrier membranes for guided tissue regeneration

This study examined the microflora in 11 barrier membranes around teeth with furcation involvement or 2 to 3 wall intrabony defects and in 16 membranes around implants with various types of bony defects. Total viable counts and the occurrence of selected microbial species were determined by non-selective and selective culture and by DNA probes. Study sites were examined for probing pocket depth and attachment level. All tooth-associated membranes yielded high levels of microorganisms. 4 of 5 teeth with membranes harboring less than 10(8) organisms gained 3 mm or more in probing attachment, whereas 6 teeth with membranes with more than 10(8) organisms exhibited loss or only small gains in attachment. 3 membranes with high levels of black-pigmented anaerobic rods lost 1 to 2 mm of attachment. Ten implant-associated membranes with no cultivable microorganisms demonstrated a mean probing gain of 4.9 mm. 6 implants with infected membranes only gained an average of 2.0 mm of supportive bone. The present findings underscore the importance of controlling or eliminating periodontal pathogens on barrier membranes in order to gain new attachment.