Detection of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis in subgingival smears by the indirect fluorescent-antibody technique

Porphyromonas gingivalis outside the oral cavity

Porphyromonas gingivalis, a Gram-negative anaerobic bacillus present in periodontal disease, is considered one of the major pathogens in periodontitis. A literature search for English original studies, case series and review articles published up to December 2019 was performed using the MEDLINE, PubMed and GoogleScholar databases, with the search terms "Porphyromonas gingivalis" AND the potentially associated condition or systemic disease Abstracts and full text articles were used to make a review of published research literature on P. gingivalis outside the oral cavity. The main points of interest of this narrative review were: (i) a potential direct action of the bacterium and not the systemic effects of the inflammatory acute-phase response induced by the periodontitis, (ii) the presence of the bacterium (viable or not) in the organ, or (iii) the presence of its virulence factors. Virulence factors (gingipains, capsule, fimbriae, hemagglutinins, lipopolysaccharide, hemolysin, iron uptake transporters, toxic outer membrane blebs/vesicles, and DNA) associated with P. gingivalis can deregulate certain functions in humans, particularly host immune systems, and cause various local and systemic pathologies. The most recent studies linking P. gingivalis to systemic diseases were discussed, remembering particularly the molecular mechanisms involved in different infections, including cerebral, cardiovascular, pulmonary, bone, digestive and peri-natal infections. Recent involvement of P. gingivalis in neurological diseases has been demonstrated. P. gingivalis modulates cellular homeostasis and increases markers of inflammation. It is also a factor in the oxidative stress involved in beta-amyloid production.

Comparing culture, real-time PCR and fluorescence resonance energy transfer technology for detection of Porphyromonas gingivalis in patients with or without peri-implant infections

BACKGROUND AND OBJECTIVE

The aim of the study was to compare the detection of Porphyromonas gingivalis using a fluorescence resonance energy transfer (FRET) technology with commonly used diagnostic methods in salivary and subgingival plaque samples from subjects with dental implants. P. gingivalis was considered as a marker for a pathogenic microbiota.

MATERIAL AND METHODS

Ninety-seven adult subjects were recruited, including periodontally healthy controls with no dental implants, implant controls with no peri-implant disease and patients with peri-implant disease. Saliva and subgingival/submucosal plaque samples were collected from all subjects and were analyzed using culture, real-time PCR and FRET technology employing P. gingivalis-specific substrates.

RESULTS

It was found that the P. gingivalis-specific substrates were highly suitable for detecting the presence of P. gingivalis in saliva and in subgingival plaque samples, showing comparable specificity to culture and real-time PCR.

CONCLUSION

We applied the FRET technology to detect P. gingivalis in implant patients with or without an implant condition and in controls without implants. The technique seems suitable for detection of P. gingivalis in both plaque and saliva samples. However, with all three techniques, P. gingivalis was not very specific for peri-implantitis cases. Future work includes fine-tuning the FRET technology and also includes the development of a chair-side application.

Microbiological profile of early onset/aggressive periodontitis patients

OBJECTIVES

The objectives of this study were to characterize the bacterial profile and to seek possible bacterial associations in the subgingival microbiota of early onset periodontitis/aggressive periodontitis patients by using two different techniques, culture and immunofluorescence.

MATERIAL AND METHODS

The study group consisted of 66 systemically healthy individuals with evidence of early onset periodontitis - 41 females and 25 males aged 23-35 years (mean 31.1 +/- 3.1 years). Bacterial samples were collected from the deepest site in each quadrant, resulting in a total of 264 sites with a mean probing pocket depth of 6.6 +/- 1.5 mm. Samples were cultured anaerobically and in 10% CO(2) using selective and nonselective media, and isolates were characterized to species level. Indirect immunofluorescence using monoclonal antibodies was applied to detect Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia (Bacteroides forsythus, Tannerella forsythensis), Prevotella intermedia/Prevotella nigrescens, Campylobacter rectus, Peptostreptococcus micros and Actinomyces israelii.

RESULTS

93.6% of sampled sites showed bleeding on probing and 23.5% were positive for suppuration. P. intermedia/P. nigrescens, P. gingivalis, and C. rectus were detected in 77.3-85.9% of samples using culture methods and in 85.6-91.3% using immunofluorescence. P. micros and A. actinomycetemcomitans were found, respectively, in 63.3% and 25.0% of all sites using culturing and in 58.7% and 27.7% sites using immunofluorescence. Significantly strong positive associations were observed between T. forsythia and C. rectus (odds ratio 109.46), and T. forsythia and P. gingivalis (odd ratio 90.26), whereas a negative association was seen between P. intermedia/P. nigrescens and A. actinomycetemcomitans (odds ratio 0.42). Coinfection by P. gingivalis, T. forsythia, P. intermedia/P. nigrescens and C. rectus was observed in 62.1% of the test sites, and in 89.4% of the studied subjects. The sensitivity of immunofluorescence for T. forsythia, C. rectus, P. intermedia/P. nigrescens and P. gingivalis was found to be very high (0.99-0.94) using culture as the reference detection method. The agreement between culture and immunofluorescence in detecting the presence or absence of the investigated species was 85.2-88.1% for P. gingivalis, P. intermedia/P. nigrescens, C. rectus, and T. forsythia, 75.9% for A. actinomycetemcomitans and 70.4% for P. micros.

CONCLUSIONS

The microbial profile of the early onset/aggressive periodontitis population was complex. The agreement between the two detection methods was very high.

Different type 1 fimbrial genes and tropisms of commensal and potentially pathogenic Actinomyces spp. with different salivary acidic proline-rich protein and statherin ligand specificities

Actinomyces spp. exhibit type 1 fimbria-mediated adhesion to salivary acidic proline-rich proteins (PRPs) and statherin ligands. Actinomyces spp. with different animal and tissue origins belong to three major adhesion types as relates to ligand specificity and type 1 fimbria genes. (i) In preferential acidic-PRP binding, strains of Actinomyces naeslundii genospecies 1 and 2 from human and monkey mouths displayed at least three ligand specificities characterized by preferential acidic-PRP binding. Slot blot DNA hybridization showed seven highly conserved type 1 fimbria genes (orf1- to -6 and fimP) in genospecies 1 and 2 strains, except that orf5 and orf3 were divergent in genospecies 1. (ii) In preferential statherin binding, oral Actinomyces viscosus strains of rat and hamster origin (and strain 19246 from a human case of actinomycosis) bound statherin preferentially. DNA hybridization and characterization of the type 1 fimbria genes from strain 19246 revealed a homologous gene cluster of four open reading frames (orfA to -C and fimP). Bioinformatics suggested sortase (orfB, orf4, and part of orf5), prepilin peptidase (orfC and orf6), fimbria subunit (fimP), and usher- and autotransporter-like (orfA and orf1 to -3) functions. Those gene regions corresponding to orf3 and orf5 were divergent, those corresponding to orf2, orf1, and fimP were moderately conserved, and those corresponding to orf4 and orf6 were highly conserved. Restriction fragment length polymorphism analyses using a fimP probe separated human and monkey and rat and hamster strains into phylogenetically different groups. (iii) In statherin-specific binding, strains of A. naeslundii genospecies 1 from septic and other human infections displayed a low-avidity binding to statherin. Only the orf4 and orf6 gene regions were highly conserved. Finally, rat saliva devoid of statherin bound bacterial strains avidly irrespective of ligand specificity, and specific antisera detected either type 1, type 2, or both types of fimbria on the investigated Actinomyces strains.

Periodontal treatment and its effects on glycemic control: a review of the evidence

Persisting poor glycemic control has been shown to be associated with the incidence and progression of diabetes-related complications. The bulk of oral health-related research has focused on the impact of diabetes on periodontal health, yet there are several lines of evidence to support the plausibility of the notion that periodontal infections contribute to problems with glycemic control. This article reviews the body of English-language literature containing reports of clinical research that has considered the relationship between treatment of periodontal diseases and improvement in glycemic control in humans. Although there is supportive clinical and epidemiologic evidence, equivocal and contrary evidence also exists. It is concluded from this review that the quantity, breadth, and strength of evidence-based knowledge are currently insufficient to establish periodontal therapy as influential in improving glycemic control in either type 1 or type 2 diabetes. Further rigorous, systematic study of the effects of treating periodontal infection on glycemic control is warranted.

Periodontitis-associated marker bacteria in an urban North American patient population: application of a commercial immunoassay

We used an immunoassay to demonstrate marker organisms (Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans) in 3 private practice populations (F-ME periodontist, 55 patients; MHM periodontist, 179 patients; and EWM general dentist, 19 patients). Occurrence of the marker organisms involves the whole oral environment, not just individual sites, as shown by close correlation between presence of the marker organisms in 2 independent sites/samples within a single mouth. Presence of the marker P. gingivalis (and P. intermedia) relates closely to periodontal pocketing while presence of A. actinomycetemcomitans does not have this pocket-associated characteristic. There was no significant relationship between presence of the marker organisms and the number of teeth in a mouth, and in the periodontal practice patients there was no significant effect of gender on occurrence of the marker organisms. A. actinomycetemcomitans and the other 2 markers were found over the entire age range (12 to 75) of our patients. Regular periodontal treatment reduced occurrence of all marker organisms and increased the frequency of marker-negative patients and sites. Occurrence of the marker organisms above immunoassay threshold levels appears to represent how receptive a patient is to each individual organism. Most patients appear receptive to the presence of P. intermedia whether treated or not. Significantly fewer patients who underwent regular treatment show the presence of P. gingivalis or A. actinomycetemcomitans when compared to untreated patients. Diagnostic application of microbial markers requires ongoing clinical assessment of patients and careful clinical judgment. 1391.

Untreated periodontal disease in Indonesian adolescents. Clinical and microbiological baseline data

At present, several risk factors for the initiation and progression of periodontitis have been identified. In order to investigate the rôle of various potential clinical and microbiological risk factors and indicators, a longitudinal study was initiated in a young population deprived from regular dental care. The present communication describes the baseline cross-sectional data obtained in 1987 in terms of the clinical periodontal condition and prevalence of periodontal bacteria in the oral cavity. All inhabitants in the age range 15-25 years of a village with approximately 2000 inhabitants at a tea estate on Western Java, Indonesia, were examined clinically and microbiologically. In total, 255 adolescents, comprising 130 males and 125 females participated in the study. Samples for bacteriological examination were taken from the gingiva, the dorsum of the tongue, and the saliva. Plaque index, bleeding upon probing, pocket depth, and attachment loss (AL) were scored on the approximal surfaces from the vestibular aspect of all teeth as well as the mid-vestibular and mid-lingual aspects of the Ramfjord teeth. Calculus was scored only on the 4 surfaces of the Ramfjord teeth. Following the clinical measurements, the deepest bleeding pocket with no clinical loss of attachment was sampled for microbiological examination. In addition, in 37 subjects a deep bleeding (> or = 4 mm) with at least 4 mm of attachment loss was sampled. Moderate periodontitis (max. AL 3-4 mm) was found in 26% of the population, advanced periodontitis (max. AL > or = 5 mm) in 8%, whereas 66% of the population showed no or minor periodontitis (max. AL 0-2 mm). Actinobacillus actinomycetemcomitans was found in 57% of the population, Porphyromonas gingivalis in 87%, Prevotella intermedia and motile rods in all cases and spirochetes in 89%. P. gingivalis (66%), A. actinomycetemcomitans (37%) and spirochetes (63%) were, of all the sampled sites of the oral cavity, most frequently detected in pockets without attachment loss. Motile rods were most prevalent on the tongue and in the saliva (92% and 89%, respectively). A high prevalence of the investigated periodontal bacteria was detected both in the pockets without and with attachment loss. No significant association between the clinical periodontal parameters and the prevalence of the microorganisms was observed at a patient level. At a site level, both P. gingivalis and spirochetes were more prevalent in sites with attachment loss. The actual rôle of these putative periodontal pathogens may be elucidated more extensively, when longitudinal data on the present population become available.

Detection of Bacteroides forsythus by immunomagnetic capture and a polymerase chain reaction-DNA probe assay

The aim of this study was to combine immunomagnetic capture and a polymerase chain reaction (PCR) followed by hybridization with a DNA probe for the detection of Bacteroides forsythus. Magnetic beads were coated with the immunoglobulin G fraction of an antiserum specific for B. forsynthus. Aliquots were incubated with various concentrations of a suspension of B. forsythus or with a suspension containing 16 bacterial species, at a concentration of 10(10) cells/ml, spiked with dilutions of B. forsythus. Beads with bound bacteria were boiled, and the target DNA in the supernatant was amplified to generate a 392-bp PCR fragment specific for B. forsythus. The amplified product was detected by dot-blot hybridization with a digoxigenin-labeled 392-bp probe. The detection limit was determined to be 10 cells/ml using immunocapture on a suspension of B. forsythus and 100 on spiked bacterial suspensions. Subgingival plaque samples were obtained from 39 Bolivian individuals with poor oral hygiene. Each sample was analyzed by the above procedure and by immunofluorescence. The overall prevalence of individuals harboring B. forsythus was 62% by immunofluorescence and 82% by PCR-DNA probe assay. The immunocapture, PCR. DNA-probe procedure should be useful for the detection of B. forsythus, particularly in false-negative samples obtained by less sensitive techniques.

An immunohistochemical study on the localization of Porphyromonas gingivalis, Campylobacter rectus and Actinomyces viscosus in human periodontal pockets

The localization and distribution of Porphyromonas gingivalis, Campylobacter rectus and Actinomyces viscosus were studied in human periodontal pockets. After obtaining voluntary consent from 9 patients, 12 teeth and their surrounding periodontal tissue with advanced adult periodontitis were extracted carefully so as not to change the structure of the periodontal pockets. The specimens were processed into serial sections. One of the sections was stained with Brown & Brenn-modified Gram stain to observe the distribution of bacteria. The others were stained immunohistochemically by the Labelled Streptavidin Biotin method (LSAB method) using specific rabbit antibodies against selected bacteria. Some bacteria could be found within epithelial cells. P. gingivalis was found in 9/12 of the samples examined. Small aggregates of P. gingivalis were scattered in all parts of the periodontal pockets, and some of these aggregates could be seen in close contact with the epithelium. Conversely, C. rectus was observed in 5/12 of the samples examined and was predominantly located in the middle and deep pocket zones. C. rectus tended to form large clumps in both the tooth-attached and epithelium-associated plaque area. A. viscosus was observed in 7/12 of the samples examined and was localized predominantly in the tooth-attached plaque area, especially in the shallow and middle pocket zones. Although unexpected spills of unattached plaque from periodontal pockets was possible, immunohistochemical staining with species-specific antibodies was extremely sensitive and revealed the localization and the distribution of periodontal disease-associated bacteria in human periodontal pockets.

Subgingival microbiota in adult Chinese: prevalence and relation to periodontal disease progression

The "checkerboard" Dna-Dna hybridization technology was used to study the epidemiology of 18 microbial species associated with various states of periodontal health and disease, in a sample of 148 Chinese subjects never exposed to systematic dental therapeutic intervention, aged 30 to 39 and 50 to 59 years. Our aims were to: 1) describe the prevalence of these microorganisms; 2) correlate the microbiological and clinical profiles of the subjects; and 3) examine the association between the microbiological variables and the longitudinal changes of periodontal status that occurred over a preceding 10-year period. A maximum of 14 subgingival samples were obtained from each subject-1,864 in all. The frequency of occurrence of the 18 species examined was high in this Chinese population, on both the subject and the tooth site level. However, all species were not found equally capable of reaching high numbers in the subgingival samples and, as a rule, colonized heavily only limited proportions of tooth sites within each mouth. There was a profound increase of certain species such as Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus in deep pockets or progressing sites. Multivariate techniques using the subgingival profile could effectively discriminate between deep/shallow pockets and progressing/ stable tooth sites. The microbiological variables showed an enhanced discriminating potential when classifications were performed on the individual subject level. Colonization by P. gingivalis, B. forsythus, Campylobacter rectus, and T. denticola at levels exceeding certain thresholds entailed a significantly increased probability (odds ratios > 4) for an individual subject to harbor deep pockets or progressing tooth sites.

Clinical and microbiological effects of subgingival antimicrobial irrigation with citric acid as evaluated by an enzyme immunoassay and culture analysis

The purpose of the present study was to compare an enzyme immunoassay with culture samples from untreated and non-surgically treated periodontal pockets and to assess the clinical and microbiological effects of citric acid irrigation as a supplement to scaling and root planing. The enzyme immunoassay used in this study is a chairside diagnostic tool aimed at identifying the presence of P. gingivalis, P. intermedia, and A. actinomycetemcomitans. Six sites with pocket depths > or = 6 mm in each of 16 patients were monitored for 24 weeks using clinical and microbiological parameters. In two out of the six sites, scaling and root planing was supplemented with subgingival citric acid irrigation of the pocket after completion of the mechanical treatment. The sensitivity of the immunoassay in relation to culture was calculated to 85.5% and the specificity to 90.2%. The immunoassay corresponded to a detection level of 10(4) as estimated by culture. Sites treated with a combination of scaling and irrigation with citric acid demonstrated a similar healing pattern as sites treated with scaling and root planing alone. The profile of the marker bacteria was almost parallel for the two groups. The results of this investigation thus indicated that the immunoassay can be used as a screening tool for selected periodontal pathogens and that adjunctive irrigation with citric acid has no measurable clinical or microbiological effects.

Principles of evaluation of the diagnostic value of subgingival bacteria

This paper describes steps in the process of evaluating subgingival bacteria assays for the diagnosis of periodontal disease. The first step examines the infectious etiology of periodontal disease in pointing to specific oral bacteria as periodontal pathogens. Second is characterization of the laboratory test to detect and quantitate these pathogens as to sensitivity, specificity, and positive and negative predictive value. Third is the role of the laboratory test in the diagnosis of the different forms of periodontal disease which is related to the current clinical rather than microbiological definition of these diseases. The fourth and most important step is an analysis of the significance of subgingival bacterial tests in clinical decision-making.

Rapid diagnosis of periodontal infections: findings in AIDS patients

A small number of bacterial pathogens in the human oral cavity cause the different forms of periodontal disease. Of the approximately two hundred different oral bacterial species, about a dozen have been associated with these diseases including localized juvenile periodontitis, rapidly progressing periodontitis, and adult periodontitis. These species include Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis, and Prevotella intermedia. Several rapid methods have been developed to detect these species in clinical samples. These include immunologic methods such as immunofluorescence, nucleic acid assays such as DNA-DNA hybridization in dot blots and enzyme assays. Immunofluorescence microscopy has been used to determine the prevalence and relative proportions of these pathogens in dental plaque samples from 194 subjects including HIV-infected and uninfected male homosexuals and intravenous drug users.

Severe periodontitis and risk for poor glycemic control in patients with non-insulin-dependent diabetes mellitus

This study tested the hypothesis that severe periodontitis in persons with non-insulin-dependent diabetes mellitus (NIDDM) increases the risk of poor glycemic control. Data from the longitudinal study of residents of the Gila River Indian Community were analyzed for dentate subjects aged 18 to 67, comprising all those: 1) diagnosed at baseline with NIDDM (at least 200 mg/dL plasma glucose after a 2-hour oral glucose tolerance test); 2) with baseline glycosylated hemoglobin (HbA1) less than 9%; and 3) who remained dentate during the 2-year follow-up period. Medical and dental examinations were conducted at 2-year intervals. Severe periodontitis was specified two ways for separate analyses: 1) as baseline periodontal attachment loss of 6 mm or more on at least one index tooth; and 2) baseline radiographic bone loss of 50% or more on at least one tooth. Clinical data for loss of periodontal attachment were available for 80 subjects who had at least one follow-up examination, 9 of whom had two follow-up examinations at 2-year intervals after baseline. Radiographic bone loss data were available for 88 subjects who had at least one follow-up examination, 17 of whom had two follow-up examinations. Poor glycemic control was specified as the presence of HbA, of 9% or more at follow-up. To increase the sample size, observations from baseline to second examination and from second to third examinations were combined. To control for non-independence of observations, generalized estimating equations (GEE) were used for regression modeling. Severe periodontitis at baseline was associated with increased risk of poor glycemic control at follow-up. Other statistically significant covariates in the GEE models were: 1) baseline age; 2) level of glycemic control at baseline; 3) having more severe NIDDM at baseline; 4) duration of NIDDM; and 5) smoking at baseline. These results support considering severe periodontitis as a risk factor for poor glycemic control and suggest that physicians treating patients with NIDDM should be alert to the signs of severe periodontitis in managing NIDDM.

The effect of periodontal treatment on periodontal bacteria on the oral mucous membranes

The aim of this study was to investigate the effect of conventional periodontal treatment on the prevalence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia on oral mucous membranes in patients with periodontitis. Fifteen patients were selected with moderate to severe periodontitis (mean age: 39.8 years, range: 26 to 58). From each patient the 4 deepest sites with bleeding on probing were selected for clinical and microbiological evaluation. At baseline, 6 weeks after oral hygiene instruction and extensive scaling and root planing, and 3 months after periodontal surgery, clinical parameters and microbiological samples including saliva, oral mucous membranes, and supra- and subgingival plaque were evaluated for the presence of the 3 test bacteria using indirect immunofluorescence. All clinical variables, except redness, showed a significant improvement after surgery. After treatment, the subgingival prevalence of the 3 putative periodontal pathogens had decreased significantly. However, almost no concomitant reduction in the prevalence of the bacteria was seen on the oral mucous membranes. This suggests that the oral mucous membranes may serve as a source for reinfection of the periodontium after treatment.

Occurrence of certain bacterial species and morphotypes in juvenile periodontitis in Chile

The occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, Fusobacterium nucleatum, Campylobacter rectus, Capnocytophaga species, and certain bacterial morphotypes was determined in 18 affected and 18 unaffected sites in 10 localized juvenile periodontitis (LJP) patients, and in 10 affected and 10 unaffected sites in 5 generalized juvenile periodontitis (GJP) patients. The subgingival proportion of the 7 bacterial species was determined by selective and nonselective culturing. The results showed that when considering the pure prevalence of bacteria ( > 0%) there were significant differences (P < 0.05) in the subgingival plaque microflora of the affected sites versus those of the unaffected sites for P. gingivalis, A. actinomycetemcomitans, P. intermedia, E. corrodens, C. rectus, and F. nucleatum in LJP, and for P. gingivalis, P. intermedia, and F. nucleatum in GJP. The mean proportions of cocci, motile rods and spirochetes were also significantly different (P < 0.05) in affected sites compared to unaffected sites. Capnocytophaga sp, F. nucleatum, P. intermedia, and E. corrodens were found in more than 75% of affected sites in LJP. When taking the approach that an organism, to be associated with periodontal disease, has to be detected above a certain minimum threshold, the results indicated that bacteria most frequently associated with LJP and GJP in Chile are P. gingivalis (66% of LJP and 80% of GJP affected sites), and A. actinomycetemcomitans (44% of LJP and 50% in GJP affected sites). Different bacterial species may be judged to be important in the disease process depending upon whether a pure bacterial prevalence, or a prevalence above a certain detection level, is considered.

Periodontopathogens in elderly Chinese with different periodontal disease experience

If an etiological relationship exists between destructive periodontal disease and putative periodontopathogens, they would be expected to have a very low prevalence in periodontally healthy elderly persons. To test this hypothesis, 2 subgroups of elderly, rural Chinese (a periodontally "best" and a "worst" group, each comprising 15 persons) were identified in 1990 from a cohort aged 55-69 years, examined in 1984. Assessment of changes in periodontal status over the 6-year period were possible by comparing detailed clinical recordings performed by the same examinator. Subgingival microbial samples were taken at the mesial aspects of an upper central incisor and a lower canine and examined for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia group, Prevotella melaninogenica group, Capnocytophaga, Selenomonas, Campylobacter rectus as well as predominant Streptococcus and Actinomyces species. During the 6 years prior to microbiological sampling, persons in the "best" group had lost an average of 1.21 +/- 0.48 mm attachment, while persons in the "worst" group had lost an average of 1.60 +/- 0.94 mm. The latter group had lost 53.3 teeth, predominantly for periodontal reasons, in contrast to 1.8 teeth lost in the "best" group. "Best" persons did not differ from "worst" persons with respect to the occurrence of the putative periopathogens, total viable count, and total streptococcal and Actinomyces recovery. Similarly, sites which had experienced an attachment loss > or = 2 mm during the 6-year period did not differ microbiologically from sites with less attachment loss. It is concluded that subgingival microbial characterization does not allow for a distinction between elderly individuals with markedly different periodontal disease experiences.

Detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides forsythus in an A. actinomycetemcomitans-positive patient population

A population of 33 subjects were selected on the basis that all had tested positive for A, actinomycetemcomitans at some time during the prior 7 years. Most subjects (31/33) belonged to families with a proband with confirmed localized juvenile periodontitis (JP); however, most subjects had no evidence of the typical lesions associated with JP. Two additional subjects with rapidly progressive periodontitis, known to be positive for A. actinomycetemcomitans, were also recruited. The patients with a history of JP had been treated, but were no longer enrolled in a regular maintenance program. With 3 exceptions, the subjects had not received any dental treatment or antibiotics in the past 3 months. One aim of the study was to determine the prevalence of A. actinomycetemcomitans, P. gingivalis, and B. forsythus in this population. The main purpose was to compare the relative sensitivity of various methods for detecting these periodontal pathogens. Pooled subgingival plaque samples were collected from all the mesial surfaces and aliquots of the suspension processed for the detection of A. actinomycetemcomitans by culture and indirect immunofluorescence (IF) to serotypes a, b, and c. P. gingivalis and B. forsythus were monitored with a DNA probe and IF. With culture, A. actinomycetemcomitans was detected in 39.4% of the samples, at a mean level of 0.64% of the cultivable counts. With IF, A. actinomycetemcomitans was detected in 81.8% of the samples, at levels of 0.40, 0.79, and 0.17% of the total counts for serotypes a, b and c respectively. Overall, IF was more likely to detect A. actinomycetemcomitans, P. gingivalis, and B. forsythus than any of the other methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiologic tests in epidemiologic studies: are they reproducible?

Microbiologic assessments are often included in longitudinal studies to elucidate the significance of the association of certain Gram-negative bacteria and the development of periodontal diseases. In such studies, the reliability of methods is crucial. There are several methods to identify putative pathogens, and some of them are commercially available. The purpose of the present study was to compare the reproducibility of four different methods for detecting Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in order to evaluate their usefulness in epidemiologic studies. The test panel consisted of 10 young subjects and 10 adult periodontitis patients. Subgingival plaque was sampled from sites showing bone loss and "healthy" control sites. The four different methods for detecting the target bacteria were 1) cultivation, 2) Evalusite (a chair-side kit based on ELISA), 3) OmniGene, Inc, based on DNA probes, and 4) indirect immunofluorescence (IIF). The test procedure was repeated after a 1-wk interval and was performed by one examiner. Sites reported to be positive for a microorganism by any of the four methods at one or both examinations were considered to be positive for that organism and included in the analysis. The reproducibility of the four methods was low. The IIF and the cultivation methods showed somewhat higher reproducibility than did the commercial systems. A second test was done for Evalusite, three paper points for sampling being used instead of one as described in the manual. The reproducibility of the second test was improved, indicating that the detection level of the system may influence the reliability.

Polymerase chain reaction for the identification of Porphyromonas gingivalis collagenase genes

Porphyromonas gingivalis has been shown to exhibit genetic diversity possibly resulting in variation of virulence. In the present study a potential virulence factor was targeted for the detection of P. gingivalis. A 548 bp fragment of the collagenase gene (prtC) from Porphyromonas gingivalis ATCC 33277 was amplified by polymerase chain reaction (PCR) using oligonucleotides derived from the middle portion of prtC. From 16 of 21 clinical P. gingivalis strains, a PCR product of similar size to the prtC could be obtained. These 16 P. gingivalis strains were confirmed as positive for prtC using DNA hybridization with a digoxigenin-labeled prtC PCR product as a probe. In 12 of the 16 prtC positive strains, the restriction analysis of the PCR products revealed fragment patterns identical to the known sequence. In the other 4 prtC positive strains, 4 distinct patterns were found. Of these strains, nucleotide sequence analysis of a 400 bp PCR product stretch revealed 79.1%, 83.0%, 84.8 and 89.5% homology with the known nucleotide sequence for this specific region. Sequence analysis of the PCR products from the ATCC 33277 strain demonstrated 93.7% homology. The limit of detection for the PCR was about 100 organisms. None of the other 48 tested strains of 16 bacterial species derived from oral and extraoral infections yielded a PCR product. The PCR was also used for the detection of prtC sequences in dental plaque. Our data indicate that not all P. gingivalis strains have prtC. Nucleotide heterogeneity exists among P. gingivalis with prtC.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow-cytometric identification and detection of Porphyromonas gingivalis by a LPS specific monoclonal antibody

The purpose of this study was to identify Porphyromonas gingivalis (P. gingivalis) by flow cytometry (FCM) using a monoclonal antibody (MAb) OMR-Bg1E directed to P. gingivalis-specific lipopolysaccharide (LPS). The P. gingivalis strains ATCC 33277, 381, ESO75, W50, and A7A1 were selected for the study. Fusobacterium nucleatum (F. nucleatum), Prevotella intermedia (P. intermedia), Campylobacter rectus (C. rectus), Streptococcus sanguis (S. sanguis) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) served as controls. A suspension of 10(7) bacteria/ml of each bacteria was prepared and then reacted with a P. gingivalis specific MAb OMR-Bg1E and fluorescein isothiocyanate (FITC) labeled second antibody. These samples were analyzed by FCM. Bacterial specific binding aggregate on data was separated out by the forward- and side-angle-scatter characteristics, while non-specific binding (NSB) was eliminated by excluding the region with mouse IgG-positive and second antibody-positive area. FCM detected a mean range of 56.2% to 97.2% P. gingivalis strains. There was a 5.1% non-specific binding using FCM to non-P. gingivalis strains. When the P. gingivalis concentration was adjusted to 10(2), 10(4), and 10(6) bacteria/ml, a detection rate of 35.7%, 48.1%, and 91.4%, was respectively observed. The lower sensitivity of the flow cytometric assay was 10(2) bacteria/ml. When P. gingivalis was added to P. intermedia suspension at 1, 20, 40, 60, and 80%, the MAb-positive fraction yielded by FCM displayed a coefficient of determination of 0.967 with the actual percentage of P. gingivalis and could be regressed to a linear function.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of sibling relationship on the periodontal condition

The purpose of this investigation was to study clinically as well as microbiologically the effect of sibling relationship on the periodontal condition in a young population with a relatively high prevalence of periodontal disease and deprived from regular dental care. In this study, 23 family units consisting of 3 more siblings were evaluated. In all, 78 subjects aged 15 to 25 years were included in the study. The mean interproximal amount of loss of attachment in this population was 0.29 mm. The individual mean ranged from 0 to 1.27 mm. In 33% of the subjects, > or = 1 sites with a probing depth of 5 mm or more in conjunction with 2 mm of attachment loss were present. The results show a significant sibship effect for: plaque, calculus, loss of attachment, spirochetes on the tongue and in the pocket, Porphyromonas gingivalis on the gingiva and in the saliva and Prevotella intermedia in the saliva. These results support the hypothesis that periodontitis aggregates in families.

Role of suspected periodontopathogens in microbiological monitoring of periodontitis

Periodontal disease is the clinical result of a complex interaction between the host and plaque bacteria. Although a specificity to some degree is found for Actinobacillus actinomycetemcomitans in localized juvenile periodontitis (LJP), it has been difficult to obtain evidence for a specific etiological role of the bacteria associated with periodontal disease in adults. What we see is the net result of host-parasite interactions which in an unpredictable moment accumulate and exceed the threshold of tissue integrity. This hypothesis is concomitant with the view of periodontal disease as a polymicrobial infection, predominantly anaerobic, which occurs commonly in the oral cavity or elsewhere in the body. Some micro-organisms (risk markers) occur more frequently than others and may significantly determine the outcome of this host-parasite interaction. Microbiological sampling and analysis seem to be of limited value in risk assessment; however, they can be used as tools in diagnosis in LJP patients and acute infections, and in treatment decision and therapy control in "refractory" patients. Suspected pathogens (risk markers) are Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and some species of spirochetes, while the roles of Prevotella intermedia, Bacteroidesforsythus, Fusobacterium nucleatum, Campylobacter rectus, and Peptostreptococcus micros are more uncertain. The presence of periodontopathogens as well as enterics, Staphylococcus aureus and Candida especially, should be considered in patients with systemic individual disorders--e.g., diabetes mellitus, neutropenia, agranulocytosis, and AIDS--or with implants.

Black-pigmented gram-negative anaerobes in periodontitis

Black-pigmented Gram-negative anaerobes have been associated with periodontal disease and tooth loss since they were first isolated by Burdon in 1928. Porphyromonas gingivalis, which is usually not isolated from children, adolescents or adults with no periodontal breakdown, has been recognized as one of the most important periodontopathogens. Its presence is strongly correlated with deep periodontal pockets, which are assumed to be its main habitat. Correlations have been shown also with attachment loss, clinical inflammation and serum antibody levels, indicating an aetiological role in the periodontal disease. Their pathogenicity in animal models resembling periodontal disease is documented. They are frequently isolated from periodontal abscesses. The relationship between Prevotella intermedia and periodontal disease is not clear. It is frequently isolated from advanced periodontitis, often as the only black-pigmented Gram-negative anaerobic species; however, the prevalence in adults with no periodontal breakdown is high. It is found frequently in periodontal abscesses and in acute necrotizing and ulcerative gingivitis. Serogroup I is found predominantly in deep periodontal pockets, whereas all serogroups (I-III) are found in shallow pockets and gingivitis. No conclusive difference in pathogenicity between serogroups has been found. Pr. melaninogenica, Pr. denticola and Pr. loescheii are frequently found in the gingival crevice in preschool children and other age groups with gingivitis, but are seldom found in deep periodontal pockets.

Comparison of the benzoyl-DL-arginine-naphthylamide (BANA) test, DNA probes, and immunological reagents for ability to detect anaerobic periodontal infections due to Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus

Most forms of periodontal disease are associated with the presence or overgrowth of anaerobic species that could include Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus among others. These three organisms are among the few cultivable plaque species that can hydrolyze the synthetic trypsin substrate benzoyl-DL-arginine-naphthylamide (BANA). In turn, BANA hydrolysis by the plaque can be associated with periodontal morbidity and with the presence of these three BANA-positive organisms in the plaque. In this investigation, the results of the BANA test, which simultaneously detects one or more of these organisms, were compared with the detection of these organisms by (i) highly specific antibodies to P. gingivalis, T. denticola, and B. forsythus; (ii) whole genomic DNA probes to P. gingivalis and T. denticola; and (iii) culturing or microscopic procedures. The BANA test, the DNA probes, and an enzyme-linked immunosorbent assay or an indirect immunofluorescence assay procedure exhibited high sensitivities, i.e., 90 ot 96%, and high accuracies, i.e., 83 to 92%, in their ability to detect combinations of these organisms in over 200 subgingival plaque samples taken from the most periodontally diseased sites in 67 patients. This indicated that if P. gingivalis, T. denticola, and B. forsythus are appropriate marker organisms for an anaerobic periodontal infection, then the three detection methods are equally accurate in their ability to diagnose this infection. The same statement could not be made for the culturing approach, where accuracies of 50 to 62% were observed.

Comparison of various detection methods for periodontopathic bacteria: can culture be considered the primary reference standard?

The development of diagnostic tests for a periodontal infection raises the issue as to what the appropriate reference standard, or "gold standard," should be for the evaluation of a new test. The present research was initiated to compare the ability of several detection methods, i.e., a serial dilution anaerobic culture and/or microscopic procedure, a DNA probe procedure, and immunological reagents using both an enzyme-linked immunosorbent assay and an indirect immunofluorescence assay to detect Treponema denticola, Porphyromonas gingivalis, Bacteroides forsythus, and Actinobacillus actinomycetemcomitans in subgingival plaque samples taken from 204 periodontally diseased tooth sites. The prevalence of the four monitored species varied as a function of both the species and the detection method. Spirochetes were present in 99% of the plaques, whereas A. actinomycetemcomitans was detected at the lowest frequency. The culture method yielded the lowest prevalence values for the three cultivable species. This raised the question as to which results, those obtained by culture or those obtained by the DNA probes and the immunological reagents, were the most reliable. This issue was addressed by looking at the prevalence profile of the monitored organisms, as determined by all the detection methods. If the species was detected by three or four of the detection methods, then it was considered present, whereas if it was absent by three or four of the detection methods, then it was considered absent. This approach showed the DNA probes and immunological reagents to be significantly superior (P less than 0.05) to the culture approach for the detection of P. gingivalis, A. actinomycetemcomitans, and B. forsythus and to be comparable to the microscopic approach in the detection of T. denticola.

Relation of baseline microbial parameters to future periodontal attachment loss

The relationship between the level of subgingival species at baseline and subsequent attachment loss in a subject was examined. 38 subjects (14-71 years) with prior evidence of periodontal destruction were monitored 2x for pocket depth and attachment level at 6 sites per tooth at baseline and 2 months. A subject was considered to exhibit new attachment loss if 1 or more sites increased 3 mm or more in attachment level in 2 months. Subgingival plaque samples were taken at the baseline visit from the mesial aspect of each tooth (28 sites) using Gracey curettes. Samples were dispersed, diluted and plated on Trypticase soy agar supplemented with 5% sheep blood. After 7 days of anaerobic incubation, the colonies were lifted onto nylon filters, lysed and the DNA fixed to the filters. Digoxygenin-labeled DNA probes were used to enumerate 14 subgingival species. 17 of 38 subjects (44.7%) exhibited new attachment loss in 2 months. The % of the total viable count of each species was averaged for each subject. The species enumerated and the mean % of the total cultivable microbiota averaged across the active and inactive subjects were as follows; B gingivalis 2.3, 1.2; W. recta 1.3, 0.6; B. intermedius I 2.5, 2.0; B. forsythus 1.5, 1.2; A. actinomycetemcomitans serotype a 1.1, 0.8; F. nucleatum ss vincentii 1.1, 1.0; S. intermedius 2.0, 1.9; P. micros 1.5, 1.5; B. intermedius II 1.6, 1.7; A. actinomycetemcomitans serotype b 0.4, 0.6; S. sanguis I 1.8, 2.1; S. sanguis II 2.7, 3.0; V. parvula 3.9, 4.2; C. ochracea 0.9, 1.8.(ABSTRACT TRUNCATED AT 250 WORDS)

Slot immunoblot assay for detection and quantitation of periodontal disease-associated microorganisms in dental plaque

A rapid method for qualitative and quantitative detection of specific oral microorganisms from subgingival dental plaque is described. Plaque samples were suspended in phosphate-buffered saline containing protease inhibitors and 0.5% formaldehyde, briefly sonicated to disperse bacterial aggregates, and applied to nitrocellulose membranes in a slot blot manifold. Subsequent incubations with species-specific rabbit antibody and anti-rabbit antibody-alkaline phosphatase conjugate and development with BCIP-NBT substrate resulted in an easily discernible, permanent stain being deposited at the sample application site. Comparison with known concentrations of pure, cultured microorganisms applied to the same membranes permitted qualitative or semiquantitative plaque characterization by visual inspection. Analysis of the blots with a computer-linked flatbed scanner provided quantitative data on microbial content. The reproducibility of the results (standard error of the mean, less than 10%) obtained with slot immunoblotting greatly exceeded that of the results obtained with immunofluorescence analysis (standard error of the mean, greater than 57%). Because it is versatile, rapid, sensitive, reproducible, permanent, and relatively inexpensive, slot immunoblotting lends itself to use in large-scale investigations for the detection and quantitation of specific microbial species.

Detection of two anaerobic periodontopathogens in children by means of the BANA and ELISA assays

The mouths of young children become colonized by a variety of bacteria, but there have been only a few studies that have sought the presence of periodontopathic species in this population. Almost all of these studies used culturing techniques rather than the newer detection methodologies for various periodontopathogens. Studies in adults have shown that Treponema denticola and Porphyromonas (Bacteroides) gingivalis can be detected in dental plaque by use of the BANA and ELISA diagnostic tests. In the present study, plaque samples from four subgingival sites in each of 157 children (aged from two to 18 years) were tested for BANA hydrolysis with a BANA reagent card, and for T. denticola and P. gingivalis with an ELISA assay. Anaerobic periodontopathogens hydrolyzing the BANA substrate were found to be present in at least one of four plaque samples in 88 children (56%). T. denticola and/or P. gingivalis were detected by ELISA in at least one plaque sample in each of 135 children (86%). This study shows that children are widely colonized by these micro-organisms. A higher proportion of Black children than Caucasian children was colonized by these BANA-positive organisms. Also, children having a parent with a documented history of periodontal disease were more likely to be BANA-positive than were children of parents with unknown periodontal status.

Application of monoclonal antibodies to the detection of black-pigmented Bacteroides spp. in subgingival plaques by immunoslot blot assay

The aim of the present study was to assess the application of monoclonal antibodies to the detection of black-pigmented Bacteroides spp. in subgingival plaques by immunoslot blot assay. Subgingival plaque samples from adult periodontal patients were examined by immunoslot blot assay with monoclonal antibodies that specifically recognize Bacteroides gingivalis, Bacteroides intermedius serogroups I and II, and Bacteroides melaninogenicus. The assay can detect specifically these Bacteroides spp. in the subgingival plaques. Therefore, we investigated the distribution of these Bacteroides spp. in the subgingival plaques of patients classified by Russell's periodontal index. Reactivities of their plaques with monoclonal antibodies toward B. gingivalis and B. intermedius serogroup I were clearly related to the severity of the periodontal disease, but this was not the case with B. intermedius serogroup II and B. melaninogenicus. These results indicate that this immunoslot blot assay using monoclonal antibodies toward these Bacteroides spp. provides simple detection and monitoring of these organisms in periodontal patients.

The microbiology of HIV-associated periodontal lesions

2 intraoral lesions associated with human immunodeficiency virus (HIV) infection have recently been described: an atypical gingivitis and a rapidly progressive periodontitis. The microbiota associated with these gingival and periodontal lesions was investigated. Subgingival plaque samples were taken from 45 HIV-seropositive homosexual men and from 44 HIV-seronegative control subjects. Each sampled site was clinically and radiographically classified as HIV-associated gingivitis, HIV-associated periodontitis, healthy in an HIV-seropositive subject, or healthy, conventional gingivitis or classical periodontitis in a control subject. Plaque samples were examined by indirect immunofluorescence with polyclonal antisera to detect Bacteroides gingivalis, B. intermedius, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans. Anaerobic culturing was used to detect black-pigmented Bacteroides species, Fusobacterium species, and A. actinomycetemcomitans to confirm the immunofluorescence findings. We detected B. gingivalis, B. intermedius, F. nucleatum, and A. actinomycetemcomitans in significantly more HIV-periodontitis sites (80, 65, 59 and 61% of sites, respectively) and HIV-gingivitis sites (61, 70, 52 and 52%, respectively) than in HIV-seropositive healthy and control sites (p less than 0.05). The results indicate that the microbiota found in HIV-periodontitis is similar to that of classical periodontitis. In contrast, however, the microbiota associated with HIV-gingivitis is strikingly different from that of conventional gingivitis. The similarity in the prevalence of periodontopathic organisms in both HIV-gingivitis and HIV-periodontitis suggests that the HIV-gingivitis lesion may be a precursor to the tissue destruction observed in HIV-periodontitis. Hence, early detection and treatment of the HIV-gingivitis lesion may prevent the rapid and extensive breakdown of periodontal tissues associated with HIV-periodontitis.

Clinical and laboratory characterization of early onset periodontitis

Clinical and laboratory data were compared in 72 patients with localized periodontitis (LP) and 103 patients with generalized periodontitis (GP). Significantly more LP than GP cases had decreased neutrophil chemotaxis (CTX), and were seropositive for Actinobacillus actinomycetemcomitans (Aa). Significantly, more GP cases were seropositive for Bacteroides gingivalis (Bg). All clinical indices were similar on affected teeth in LP and GP, but the attachment loss was greater on clinically unaffected teeth in GP when compared with LP. LP cases with CTX defects had a significantly lower mean age, were more often seropositive for Aa antibodies, and were more often female than LP patients with normal CTX. Significantly more GP cases with CTX defects were seropositive for Aa antibody. GP patients with normal CTX had a higher plaque index on both affected and unaffected teeth than did GP patients with a CTX defect. Our data suggest that chemotaxis and/or specific bacteria may be contributory, but not always necessary, factors in these disorders. The overlap in clinical and laboratory profiles of LP and GP continues to cloud the distinction of these early onset forms of periodontitis.

Actinobacillus actinomycetemcomitans serotypes and leukotoxicity in Korean localized juvenile periodontitis

Actinobacillus actinomycetemcomitans is though to play an important role in the pathogenesis of localized juvenile periodontitis (LJP). Preliminary data suggested that the serotype distribution of A. actinomycetemcomitans in Korea and the United States differ. This study evaluated A. actinomycetemcomitans prevalence, serotype distribution, and leukotoxicity in Korean LJP patients by culture, enzyme-linked immunosorbent assay, indirect immunofluorescence, and lactate dehydrogenase release from polymorphonuclear leukocytes exposed to A. actinomycetemcomitans. A. actinomycetemcomitans occurred in 75% of LJP lesions and 6% of normal sites with approximately equal distribution of serotype a, b, and c. Single serotypes were isolated from nine patients while three patients harbored two serotypes either in the same or different disease sites. A. actinomycetemcomitans leukotoxicity occurred in 22% isolates with a 69% prevalence. Individual sites harbored both leukotoxic and non-leukotoxic strains with no serotype association. The distribution of serotypes and leukotoxic strains of A. actinomycetemcomitans in Korean LJP patients differed from those reported in the United States. This suggests that serotype b may not be more important in the pathogenesis of LJP.

Cell surface protein antigen from Wolinella recta ATCC 33238T

A high-molecular-weight (approximately 150,000) protein was selectively isolated by acid extraction from the cell surface of Wolinella recta and purified by negative adsorption on DEAE-cellulose and gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that this protein was found in W. recta but not in other Wolinella species, such as W. curva and W. succinogenes. Sera from patients with periodontitis reacted strongly with this protein antigen, whereas sera from healthy donors showed little or no reactivity, as determined by immunoblotting analysis. In serum, titers of immunoglobulin G antibodies to the protein antigen were significantly higher in patients with periodontitis than in periodontally healthy donors, as detected by an enzyme-linked immunosorbent assay.

Effects of subgingival irrigation on A. actinomycetemcomitans

The effects of repeated subgingival irrigation on Actinobacillus actinomycetemcomitans was examined. 24 periodontal pockets harboring A. actinomycetemcomitans in 3 juvenile and 4 adult periodontitis patients were studied. The protocol included bi-weekly subgingival irrigation with hydrogen peroxide of the periodontal sites until the micro-organism was no longer detected by selective culture, or for 6 months. A. actinomycetemcomitans was gradually suppressed to below detection following the irrigation regime and could no longer be detected in 46% of the sites at completion of the irrigation protocol. The sites were microbiologically re-examined 5 months after cessation of the irrigation regime. A. actinomycetemcomitans re-occurred in only 2 of the sites from which it had originally been suppressed below detection. The results indicate: (1) that the irrigation regime tested has some potential to suppress A. actinomycetemcomitans in periodontal pockets; (2) that the effect of the irrigation protocol generally lasted for 5 months; (3) that the reduction rate of A. actinomycetemcomitans to below detectable levels seems related to the initial number of cultivable bacteria from the periodontal pocket.

The role of spirochetes in periodontal disease

The spirochetal accumulation in subgingival plaque appears to be a function of the clinical severity of periodontal disease. It is not known how many different spirochetal species colonize the plaque, but based upon size alone, there are small, intermediate-sized, and large spirochetes. Four species of small spirochetes are cultivable, and of these, T. denticola has been shown to possess proteolytic and keratinolytic enzymes as well as factors or mechanisms which suppress lymphocyte blastogenesis and inhibit fibroblast and polymorphonuclear leukocyte (PMNL) function. All of these attributes could contribute to periodontal tissue insult. Yet independent of these potential virulence mechanisms, the overgrowth of spirochetes can be clinically useful if simply interpreted as indicating the result of tissue damage. In this case, the spirochetes would be indicators of disease and could be easily monitored by microscopic examination of plaque, or possibly by the measurement of benzoyl-DL-arginine-2-naphthylamide (BANA) hydrolytic activity in the plaque.

Clinical, microbiological and immunological features of subjects with refractory periodontal diseases

27 subjects with active destructive periodontal diseases were treated by modified Widman flap surgery and systemic tetracycline and divided into 4 groups based on pre- and post-therapy hazard rates (% of sites losing greater than 3 mm of attachment in 1 year). Pre- and post-therapy hazard rates were respectively: group I (3 subjects) less than 4 and less than 4; group II (8 subjects) greater than 4 and less than 4; group III (3 subjects) less than 4 and greater than 4; group IV (refractory group of 13 subjects) greater than 4 and greater than 4. Baseline mean pocket depths and attachment loss of groups I and II subjects were less than groups III and IV subjects and exhibited less suppuration. 6 group IV subjects lost a total of 38 teeth after therapy, in contrast to no tooth loss in subjects in the other 3 groups. Redness, bleeding on probing, plaque levels and age did not differ among groups. Subjects in the 4 groups differed in the subgingival species to which they showed elevated serum antibody responses. Group IV subjects showed elevated responses to a select range of gram-negative species, including A. actinomycetemcomitans strains Y4 or ATCC 29523, F. nucleatum and B. intermedius. No subject in any of the other groups exhibited an elevated response to B. intermedius. The mean % of each species in all sampled sites, both before and after therapy, was computed for each subject. Subjects in groups III and IV (high post-therapy hazard rates) exhibited elevated mean levels of B. forsythus, F. nucleatum, S. intermedius, E. corrodens, and B. gingivalis.(ABSTRACT TRUNCATED AT 250 WORDS)

A rationale for monitoring the periodontal microbiota after periodontal treatment

Strict control of dental plaque accumulation remains the cornerstone of successful maintenance of the treated patient. However, some recurrences of periodontitis appear to take place despite good oral hygiene habits. A proportion of these are likely due to qualitative features of the periodontal microbiota rather than merely increased mass. Microscopic as well as cultural monitoring of qualitative features of the periodontal microbiota may be helpful in detecting critical changes. This review presents some of the research findings that provide a rationale for microbiological monitoring. Some of the advantages as well as difficulties encountered with these procedures are discussed.

Effect of modified Widman flap surgery and systemic tetracycline on the subgingival microbiota of periodontal lesions

33 subjects with evidence of active destructive periodontal disease were treated by modified Widman flap surgery and systemic tetracycline (1 g/day for 21 days). Subgingival plaque samples were taken from 41 sites in 12 of these subjects before and 6 months after therapy for predominant cultivable microbiota studies. Mean pocket depth and attachment levels in the 41 sampled sites were 7.1 +/- 2.9 mm and 7.7 +/- 3.2 mm prior to therapy and 4.8 +/- 2.3 mm and 6.2 +/- 3.4 mm after therapy. B. melaninogenicus and V. parvula were more frequently detected in samples taken after therapy, while S. intermedius, S. morbillorum, S. uberis and W. recta were less frequently detected after therapy. A. actinomycetemcomitans were detected in 7 sites pretherapy and 1 site post therapy. The frequency of detection of B. gingivalis and B. intermedius was virtually unchanged. The mean levels of the Actinomyces sp., A. actinomycetemcomitans, B. gingivalis, B. intermedius, S. morbillorum, S. uberis and W. recta were decreased after therapy, while the mean levels of B. melaninogenicus, S. mitis, S. sanguis II and V. parvula were increased after therapy. V. parvula showed the greatest increase to 8.2% of the microbiota. In the second phase of the study, subgingival plaque samples from 94 sites in the 33 treated subjects were analyzed by predominant cultivable techniques. As a result of therapy, 24 sites exhibited attachment loss greater than 2 mm, 23 sites exhibited "gain" greater than 2 mm and the remaining 47 sites were considered to be unchanging.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue localization of Actinobacillus actinomycetemcomitans in human periodontitis. II. Correlation between immunofluorescence and culture techniques

Recent immunohistological studies have suggested that Actinobacillus actinomycetemcomitans is present in the gingival tissues in juvenile periodontitis lesions. The present study examined tissue bound A. actinomycetemcomitans by bacterial culture and immunohistological demonstration of antigen in tissue. A total of 14 periodontitis lesions were examined. Eleven biopsies were obtained from gingiva adjacent to A. actinomycetemcomitans infected pockets, while the remaining three control biopsies were obtained from gingiva adjacent to pockets where subgingival A. actinomycetemcomitans infection could not be detected. Each biopsy was hemisected, one half was used for immunofluorescence microscopic examination while the other half was processed for culture of A. actinomycetemcomitans. The latter section was surface-disinfected, repeatedly washed and then minced to release bacteria from within the tissues. Aliquots from the serial washings and the minced tissue suspension were cultured on medium selective for A. actinomycetemcomitans. Surface disinfection and serial washings gradually decreased cultivable A. actinomycetemcomitans in the washings aliquots. Following tissue disruption, an increase in colony-forming units of A. actinomycetemcomitans was seen from eight of the 11 test biopsies. This bacterium could not be detected in washings or minced tissue suspensions from the control biopsies obtained from lesions in which subgingival A. actinomycetemcomitans was previously not detected. A positive correlation was seen between the presence of A. actinomycetemcomitans antigens in the gingival biopsies and; (1) A. actinomycetemcomitans colony-forming units released from the minced tissues (r = 0.90, p = 0.000), as well as; (2) the colony-forming units from the periodontal pocket (r = 0.62, P = 0.017).(ABSTRACT TRUNCATED AT 250 WORDS)