Identification of Actinobacillus actinomycetemcomitans in subgingival plaque by PCR

The effect of metronidazole on the presence of P. gingivalis and T. forsythia at 3 and 12 months after different periodontal treatment strategies evaluated in a randomized, clinical trial

OBJECTIVE

The benefit of full-mouth disinfection (FDIS) over traditional scaling and root planing (SRP) in the treatment of chronic, destructive periodontitis remains equivocal and it is not known whether the use of adjunctive antibiotics may enhance the effect of FDIS. Therefore, the aim of this study was to evaluate the effect of conventional SRP completed over 21 days or 1-day FDIS, with or without systemically delivered adjunctive metronidazole (MET) on the presence of P. gingivalis and T. forsythia after 3 and 12 months.

MATERIALS AND METHODS

One hundred and eighty-four patients with moderate-to-severe periodontitis were randomly allocated to one of four treatment groups; (1) FDIS+MET; (2) FDIS+placebo; (3) SRP+MET; (4) SRP+placebo. Prior to treatment, pooled subgingival samples were obtained from the five deepest pockets. The same sites were sampled again 3 and 12 months after treatment. All samples were analyzed for P. gingivalis and T. forsythia by PCR, whereas A. actinomycetemcomitans and other bacteria were identified by culture techniques.

RESULTS

At baseline, 47% of the samples were positive for P. gingivalis, while almost all samples were positive for T. forsythia. The occurrence of P. gingivalis and T. forsythia was significantly reduced at 3 and 12 months after treatment in the FDIS+MET group, but not in the other treatment groups.

CONCLUSION

FDIS+MET had a significant effect in patients with P. gingivalis and T. forsythia, resulting in a significant reduction in number of patients where these micro-organisms could be detected at 3 and 12 months post-therapy.

Microbiologic Observations After Four Treatment Strategies Among Patients With Periodontitis Maintaining a High Standard of Oral Hygiene: Secondary Analysis of a Randomized Controlled Clinical Trial

BACKGROUND

The benefit of full-mouth disinfection (FDIS) over traditional scaling and root planing (SRP), with or without adjunctive metronidazole, when treating chronic destructive periodontitis remains equivocal, as does the long-term association between clinical and microbiologic outcomes after such strategies. The aim of this study is to examine the relationship between clinical and microbiologic outcomes of four different treatment strategies for chronic destructive periodontitis among patients who maintain excellent oral hygiene and low gingival bleeding scores.

METHODS

One hundred eighty-four patients with periodontitis and capable of maintaining a high standard of oral hygiene were randomly allocated to one of four treatment groups: 1) FDIS + metronidazole; 2) FDIS + placebo; 3) SRP + metronidazole; and 4) SRP + placebo. Recordings of plaque, bleeding on probing, probing depth (PD), and clinical attachment level were carried out in four sites per tooth at baseline, 3 and 12 months after treatment. Before treatment, pooled subgingival samples were obtained from the five deepest pockets, which were sampled again 3 and 12 months after treatment. Microbiologic assessments of eight putative periodontal pathogens were performed using the checkerboard DNA-DNA hybridization method.

RESULTS

Levels of bacterial species were already relatively low at baseline. The only microbial factor statistically significantly associated with the clinical outcomes of treatment after 12 months was the association between reductions of Tannerella forsythia and being free from PD ≥5 mm.

CONCLUSION

In this clinical trial, the only microbial factor associated with the clinical outcomes after 12 months was a statistically significant association between the reductions of T. forsythia and being free from PD ≥5 mm.

Rapid identification of oral isolates of Aggregatibacter actinomycetemcomitans obtained from humans and primates by an ultrafast super convection based polymerase chain reaction

Aggregatibacter actinomycetemcomitans is a Gram negative oral bacterium associated with localized aggressive periodontitis (LAP). Detection of A. actinomycetemcomitans in clinical samples is routinely done by PCR. Our aim was to develop a rapid and reliable PCR method that can be used as a chair-side tool to detect A. actinomycetemcomitans in clinical samples. Sensitivity and specificity assessment was performed on buccal and plaque samples obtained from 40 adolescents enrolled in an ongoing LAP study by comparing 20 A. actinomycetemcomitans-positive subjects and 20 who were negative. In a second study, A. actinomycetemcomitans presence was tested in oral samples from eighty-six primates that included rhesus monkeys, chimpanzees, marmosets, tamarins and baboons. All samples were processed for detection of A. actinomycetemcomitans by means of culture, conventional PCR (cPCR) and rapid PCR (rPCR) using a Super Convection based AmpXpress thermal cycler (AlphaHelix, Sweden). For human samples, culture, cPCR and rPCR showed perfect agreement. Using this method A. actinomycetemcomitans was detected in 27 of 32 rhesus monkeys, 4 of 8 chimpanzees and 1 of 34 marmosets. Rapidity of AmpXpress thermal cycler, combined with Ready-To-Go PCR beads (GE Life sciences), a quick DNA extraction kit (Epicentre Biotechnologies, Madison, Wisconsin, USA) and a bufferless fast agarose gel system, made it possible to obtain results on A. actinomycetemcomitans detection within 35 min. We conclude that AmpXpress fast PCR can be conveniently used as a chair-side tool for rapid detection of A. actinomycetemcomitans in clinical samples.

Bone microbial contamination influences autogenous grafting in sinus augmentation

BACKGROUND

The oral occurrence of putative microbial pathogens in humans has been documented in health and disease. The presence of periodontopathogens in patients with a history of periodontal disease may have a negative impact on bone regeneration. This investigation was conducted to confirm the presence of periodontal pathogens in bone particles harvested intraorally for maxillary sinus augmentation and to assess the clinical and radiographic outcomes 6 to 12 months after bone augmentation.

METHODS

Culture and polymerase chain reaction (PCR)-based identification were performed by paper-point sampling of intraorally harvested bone particles in a group of 12 maintenance patients undergoing maxillary sinus augmentation. Radiographs were taken to assess and compare bone healing and volume gain at baseline and at 6 to 12 months after augmentation.

RESULTS

The presence of periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans [previously Actinobacillus actinomycetemcomitans], Prevotella intermedia, Tannerella forsythia [previously T. forsythensis], Fusobacterium nucleatum, Parvimonas micra [previously Peptostreptococcus micros or Micromonas micros], Campylobacter rectus, enteric Gram-negative rods, and Dialister pneumosintes) was identified in 10 of 12 patients (83%) by culture, PCR, or both and was associated with greater bone volume loss at 6 months postaugmentation. The PCR-positive triad, P. gingivalis, A. actinomycetemcomitans, and P. intermedia, was associated with pronounced volume loss of the grafted sinus at 6 months.

CONCLUSIONS

To the best of our knowledge, this is the first study to confirm osseous microbial contamination with major periodontopathogens in individuals undergoing maxillary sinus augmentation with a history of periodontitis. The effect on the grafting outcome translated into bone volume loss in the grafted sinus 6 months postaugmentation. Specific microbial contamination may have an impact on osteogenesis in osseous regeneration.

Periodontal pathogens in atheromatous plaques isolated from patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

It has been suggested that chronic infections may predispose to cardiovascular disease. The relationship between periodontal disease and cardiovascular disease has been a subject of increasing research in recent years. The isolation and identification of periodontal bacteria from atheromatous plaque can contribute to our knowledge of this vascular disease. The aim of this study was to isolate and identify periodontal bacteria from the periodontal pockets of different patients and to compare them with the microorganisms detected in the atheromatous plaques obtained from the same patients.

MATERIAL AND METHODS

Clinical isolates were obtained from 12 patients with periodontal wounds and atheromathous plaques. These samples were cultured in the appropriate bacteriological culture media and incubated in an anaerobic system. Periodontal bacteria were identified using polymerase chain reaction (PCR) assays.

RESULTS

From the 12 patients studied, nine presented different periodontopathic bacterial species. In two, Actinobacillus actinomycetemcomitans was present in the periodontal pockets and the respective atheromatous plaques.

CONCLUSION

The presence of A. actinomycetemcomitans in atheromatous plaques and the periodontal pockets of the same patients could indicate a role for periodontal pathogenic bacteria in the atherosclerosis disease process.

Adjunctive Antimicrobial Therapy of Periodontitis: Long-Term Effects on Disease Progression and Oral Colonization

BACKGROUND

This study assessed the long-term effects of adjunctive antimicrobial therapy on periodontal disease progression and oral colonization.

METHODS

Patients with previously untreated chronic periodontitis and subgingival Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis were randomly assigned to subgingival scaling without (control group) or with systemic amoxicillin plus metronidazole and CHX irrigation (test group). Relative attachment levels were determined and subgingival and mucosal plaque samples were taken at baseline, at 10 days (plaque only) and at 3, 6, 9, 12, 18, and 24 months following initial therapy. During maintenance therapy, patients received supragingival debridement only.

RESULTS

After 24 months, the 18 test group patients showed at sites with initial probing depths (PD) > or =7 mm a significantly (P <0.05) higher frequency of 2 mm or more attachment gain (37.3% +/- 4.6%) and lower frequency of attachment loss (7.2% +/- 3.1%) compared to the 17 controls (8.2% +/- 3.9% and 19.1% +/- 13.1%, respectively). Compared to controls, the intraoral prevalence of A. actinomycetemcomitans (up to 18 months) and P. gingivalis (up to 3 months) decreased and that of Eikenella corrodens (at 10 days) increased in test patients (P <0.05). In both treatment groups, the detection frequency of Tannerella forsythensis decreased transiently, while an overall increase was recorded for Treponema ssp.

CONCLUSIONS

Over the 24-month period, a single course of the administered adjunctive antimicrobial therapy led to a relative risk reduction of 62% for attachment loss at deep sites. However, with the exception of A. actinomycetemcomitans, it failed to induce long-term changes in the prevalence profiles of oral colonization.

Improved PCR for detection of the highly leukotoxic JP2 clone of Actinobacillus actinomycetemcomitans in subgingival plaque samples

The JP2 clone of Actinobacillus actinomycetemcomitans is associated with early-onset periodontitis in certain ethnic populations of African origin. Here, we describe and evaluate a set of primers for PCR to assay for the presence of A. actinomycetemcomitans and to discriminate between JP2-like strains and other genotypes in subgingival plaque samples.

Multifactorial assessment of predictors for prevention of periodontal disease progression

Univariate approaches have identified single factors influencing periodontal disease progression. The aim of this explorative approach was to assess the influence of various predictive factors responsible for the prevention of periodontal disease progression in the same patient sample. Patients with untreated chronic periodontitis underwent subgingival debridement alone or in combination with adjunctive antimicrobial therapy (systemic amoxicillin and metronidazole/7 days plus supragingival CHX irrigation). Supportive periodontal therapy was performed over a 24-month period. As predictors, clinical, microbial, immunological, and genetic parameters were assessed. The primary outcome variable was the percentage of teeth without attachment loss >/=2 mm over the study period (stability of attachment). At 24 months, multiple regression analysis identified adjunctive antimicrobial therapy for teeth with initially at least one site showing a pocket probing depth of >/=7 mm and IgG(4) reactivity against a 110-kDa protein of A. actinomycetemcomitans at teeth with initial pocket probing depths </=6 mm as main predictors of long-term attachment stability ( p<0.05). Other parameters failed to influence treatment outcome. Adjunctive antimicrobial therapy and antibody reactivity may be dominant factors influencing the prevention of attachment loss in patients receiving periodontal therapy.

Guided tissue regeneration using a polylactic acid barrier. Part I: Environmental effects on bacterial colonization

OBJECTIVES

The purpose of this study was to assess the dynamics of bacterial colonization in intra-osseous defects following guided tissue regeneration (GTR) therapy using a resorbable barrier.

PATIENTS AND METHODS

In each of 30 patients, one intra-osseous defect was treated with GTR using a polylactic acid membrane (Guidor). Plaque samples were taken from the defect site, other teeth and mucous membranes following initial therapy (baseline), and at 3, 6 and 12 months after periodontal surgery. Additionally, samples were taken from the defect sites at 1, 2 and 4 weeks. Actinobacillus actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), and Bacteroides forsythus (B.f.) were detected by polymerase chain reaction (PCR). Supportive periodontal therapy was performed at 3-month intervals.

RESULTS

In the 29 patients completing the study, the assessed microflora was detected in 3 (A.a.), 13 (P.g.) and 14 (B.f.) defect sites at baseline, in 2 (A.a.), 2 (P.g.) and 2 (B.f.) following surgical debridement, and in 6 (A.a.), 10 (P.g.) and 22 (B.f.) at 12 months. Defect site colonization following GTR therapy was significantly correlated with presurgical colonization at other assessed teeth (A.a. and P.g.: tau = 0.45 and 0.66, respectively; P < 0.001), or on mucous membranes (B.f.: tau = 0.44, P < 0.001).

CONCLUSION

The colonization of periodontal pathogens at sites treated by GTR may correlate with the intra-oral presence of these pathogens before surgery. If colonization of GTR sites by periodontal pathogens is to be prevented, intra-oral suppression/eradication of these pathogens may be required before surgery.

Actinobacillus actinomycetemcomitans in destructive periodontal disease. Three-year follow-up results

BACKGROUND

Convincing data exist that A. actinomycetemcomitans is an etiologic agent of periodontal disease. The purpose of this longitudinal study was to evaluate A. actinomycetemcomitans as a diagnostic indicator for periodontal disease in treated and periodontally maintained patients.

METHODS

Following comprehensive mechanical/surgical and supportive amoxicillin plus metronidazole therapy in 13 subjects with A. actinomycetemcomitans-associated destructive periodontal disease, we monitored subgingival A. actinomycetemcomitans at 4 individual sites in each patient up to 3 years post-therapy. The periodontal status was determined, and A. actinomycetemcomitans levels were quantitatively enumerated on TSBV agar in CFU/ml. Six patients with a persistence of subgingival A. actinomycetemcomitans at each reexamination within 3 years post-therapy were selected to be at risk for minor periodontal treatment outcomes and further recurrence of periodontal disease (test group). Seven subjects with a complete suppression of A. actinomycetemcomitans at each post-therapy visit served as controls.

RESULTS

The periodontal parameters decreased from overall values of 6.39 mm (probing depth, PD) and 7.64 mm (clinical attachment level, CAL) at the outset to 3.81 mm (PD) and 5.62 mm (CAL) 2 years post-therapy (Friedman, P< or =0.05). At the 3-year reexamination, the PD/CAL scores increased to 4.03/5.78 mm. Among the 6 individuals (46%) with persistence of subgingival A. actinomycetemcomitans at the final 3-year visit (test group), periodontal status yielded increased levels of 4.45 mm (PD) and 6.60 mm (CAL). The control subjects (n = 7) revealed lower values of 3.67 mm (PD) and 5.09 mm (CAL). However, on a patient level, during the 3-year observational trial, the periodontal status of the 13 individuals was not statistically affected by subgingival infection with A. actinomycetemcomitans.

CONCLUSIONS

Although in advanced periodontal disease, comprehensive mechanical and antimicrobial treatment is an appropriate regimen for sustained improvement of periodontal health, long-term control of subgingival infection with A. actinomycetemcomitans could not be achieved. In the maintenance care of destructive periodontitis, the persistence of A. actinomycetemcomitans is not a diagnostic parameter for periodontal disease.

Interleukin-1 haplotype and periodontal disease progression following therapy

The purpose of this study was to assess the prognostic value of the IL-1 haplotype on the progression of periodontal disease following therapy. 48 adult patients with untreated periodontitis harboring Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis were randomly assigned to receive full-mouth scaling alone (control) or in combination with systemic metronidazole plus amoxicillin and supragingival irrigation with chlorhexidine digluconate (test). All patients received supportive periodontal therapy at 3 to 6 months intervals. In 33 patients, lymphocyte DNA was analyzed for polymorphism in the IL-1A gene at position -889 and IL-1B gene at position +3953. Overall, 16 of 33 patients (7 of 17 test and 9 of 16 control) carried the IL-1 haplotype. 2 years following initial periodontal therapy, no differences in the survival rates of sites or teeth not exhibiting probing attachment loss of 2 mm or more compared to baseline, were found between patients who tested positive (85% sites, 53% teeth) and patients who tested negative (89% sites, 56% teeth) for the IL-1 haplotype. The results indicated that the IL-1 haplotype may be of limited value for the prognosis of periodontal disease progression following non-surgical periodontal therapy.

Clonal infection with Actinobacillus actinomycetemcomitans following periodontal therapy

Mechanical debridement results in a shift of the bacterial composition in the periodontal pocket on the species level. It is unknown, however, whether a clonal change within a species could lead to the emergence of strains with different levels of virulence. Therefore, in the present study, the genetic variability of Actinobacillus actinomycetemcomitans was assessed and strains identified which were associated with periodontal disease progression following periodontal therapy, i.e., refractory periodontitis. Twenty adult patients with untreated periodontitis and subgingival colonization of A. actinomycetemcomitans were randomly assigned to receive full-mouth scaling alone or scaling with an adjunctive antimicrobial therapy. Both groups received supportive periodontal therapy at 3, 6, 9, 12, 18, and 24 months. Subgingival plaque samples were taken at every visit; venous blood was obtained at 24 months only. A. actinomycetemcomitans isolates were typed by the RAPD method, and antibody reactivity against outer membrane proteins was assessed by immunoblot analysis. Eleven distinct RAPD patterns were found in 18 patients completing the study. All patients harbored only one A. actinomycetemcomitans genotype, and within each patient this genotype persisted throughout the 24-month observation period. No differences in the expression of antibody reactivity against outer membrane proteins were found between strains isolated at baseline and at 24 months. Three genotypes were associated with reduced survival rates of teeth without probing attachment loss of 2 mm or more. The results indicated that (i) most patients harbored only one A. actinomycetemcomitans genotype; (ii) the genotype persisted following therapy; and (iii) only some genotypes were associated with refractory periodontitis.

Detection of Treponema socranskii associated with human periodontitis by PCR

A PCR technique was used to detect and identify Treponema socranskii associated with periodontitis. A species-specific forward primer was designed for a variable region within its 16S rRNA gene and was used in conjunction with a conserved reverse primer. This primer pair was tested for specificity against 44 oral bacterial strains. Sensitivity was determined using a serial dilution of T. socranskii cells. Amplification products were obtained from all T. socranskii strains tested, but not from other oral bacteria associated with periodontal disease. The detection limit of PCR was 5 T. socranskii cells per PCR. T. socranskii was detected by PCR in subgingival plaque and saliva samples from patients with periodontitis.

Simultaneous detection of Bacteroides forsythus and Prevotella intermedia by 16S rRNA gene-directed multiplex PCR

In a 16S rRNA gene-directed multiplex PCR, Prevotella intermedia- and Bacteroides forsythus-specific reverse primers were combined with a single conserved forward primer. A 660-bp fragment and an 840-bp fragment that were specific for both species could be amplified simultaneously. A total of 152 clinical samples, subgingival plaque and swabs of three different oral mucosae, from 38 periodontitis patients were used for the evaluation.

Evaluation of two commercial kits and arbitrarily primed PCR for identification and differentiation of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus

The closely related species Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus are common findings in oral microbiota. The aims of this study were to evaluate the applicability of the Rapid NH and API ZYM kits and arbitrarily primed PCR (AP-PCR) in the identification and differentiation of the three species from each other. The material included 62 clinical isolates and three reference strains of A. actinomycetemcomitans representing the 5 serotypes and 18 AP-PCR genotypes. Haemophilus species included 12 clinical isolates and 11 reference strains of H. aphrophilus, H. paraphrophilus, and 5 other species. For the PCR amplification, the oligonucleotide 5'-CAGCACCCAC-3' was used as a primer. Contrary to the consistent performance of API ZYM, the Rapid NH system was able to identify only 10 of 65 (15%) A. actinomycetemcomitans isolates, whereas all Haemophilus species were correctly identified. The API ZYM test differentiated A. actinomycetemcomitans from H. aphrophilus and H. paraphrophilus by negative beta-galactosidase and alpha-glucosidase reactions and a positive esterase lipase reaction. However, the API ZYM test was unable to differentiate H. aphrophilus from H. paraphrophilus, it also could not differentiate A. actinomycetemcomitans serotypes from each other. Among the H. aphrophilus isolates three AP-PCR genotypes and among H. paraphrophilus isolates only one AP-PCR genotype, distinct from those of A. actinomycetemcomitans, were found. The Rapid NH test showed poor ability to identify clinical isolates of all A. actinomycetemcomitans serotypes. Moreover, AP-PCR genotyping proved to be a rapid method for the species differentiation of A. actinomycetemcomitans, H. aphrophilus, and H. paraphrophilus.

Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in young Chinese adults

The aim of this study was to determine the presence or absence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in young Chinese adults and to examine the A. actinomycetemcomitans isolates from positive subjects with regard to the serotype distribution, presence of the leukotoxin gene lktA and the promoter for the leukotoxin operon as well as the incidence of phage Aa phi 23. Sixty subjects, working in a knitting factory in the Province of Guangzhou, People's Republic of China, were investigated. Subgingival microbial samples were taken from both upper first molars. They were cultured both anaerobically and in 5% CO2. P. gingivalis was found in 33 subjects. On average, it constituted 7% of the total anaerobic cultivable counts. A. actinomycetemcomitans was detected in 37 subjects of which seven yielded counts > 10(5). Twenty-one subjects were positive for both organisms. A. actinomycetemcomitans serotype a was found in 9 subjects, serotype c was found in 23 and serotype e in 5. A. actinomycetemcomitans serotypes b and d were not detected in any subjects. Presence of the leukotoxin gene lktA was demonstrated for all A. actinomycetemcomitans isolates; however, none of the A. actinomycetemcomitans strains from the present study had a deletion in the promoter region of the leukotoxin operon. The results of this investigation show a high frequency of the putative periodontal pathogens P. gingivalis and A. actinomycetemcomitans and corroborate the concept that there is variation in virulence and pathogenic potential among isolates from different subjects.

Actinobacillus actinomycetemcomitans in the human oral microflora

In this paper, the frequency of the microaerophilic gram-negative bacterium Actinobacillus actinomycetemcomitans (Ac) which is a component of the normal human oral microflora was investigated. Ac could be cultivated from oral material (molar sulcus and/or mucous membrane of the cheek) from 55 out of 405 healthy adults examined. This overall Ac frequency of 13.6% corresponds well to the few other reports existing in literature. A short discussion about the possible pathogenic potential of Ac is given at the end of the paper.

Differential clinical treatment outcome after systemic metronidazole and amoxicillin in patients harboring Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis

48 adult patients with untreated periodontitis harboring subgingival Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis as assessed by PCR were randomly assigned to receive full-mouth scaling alone (control) or scaling with systemic metronidazole plus amoxicillin and supragingival irrigation with chlorhexidine digluconate (test). In patients harboring A. actinomycetemcomitans intraorally at baseline, the adjunctive antimicrobial therapy resulted in a significantly higher incidence of probing attachment level (PAL) gain of 2 mm or more compared to scaling alone over 12 months (p<0.05). In addition, suppression of A. actinomycetemcomitans in subgingival plaque below detectable levels was associated with an increased incidence of PAL gain. In contrast, patients initially harboring P. gingivalis but not A. actinomycetemcomitans in the oral cavity showed a significantly higher incidence of PAL loss following adjunctive antimicrobial therapy compared to scaling alone (p<0.05). When the presence of pathogens at baseline was disregarded in the analysis, adjunctive antimicrobial therapy did not significantly enhance clinical treatment outcome. The results indicated that adults with untreated periodontitis harboring A. actinomycetemcomitans may benefit from the adjunctive antimicrobial therapy for a minimum of 12 months, whereas, the regimen may adversely affect the clinical treatment outcome of patients harboring P. gingivalis but not A. actinomycetemcomitans.

Differential effects of systemic metronidazole and amoxicillin on Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in intraoral habitats

48 adult patients with untreated periodontitis harboring subgingival Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis were randomly assigned to receive full mouth scaling alone (control) or scaling with systemic metronidazole plus amoxicillin and supragingivai irrigation with chlorhexidine digluconate (test). Subgingival plaque and swab samples from tongue, tonsils, and buccal mucosa were taken at baseline, 10 days and 3, 6, 9, and 12 months. A. actinomycetemcomitans was detected in the oral cavity, i.e., subgingival plaque and/or mucous membranes, less frequently in test patients compared to controls at 9 and 12 months (p<0.01), whereas, the intraoral detection frequency of P. gingivalis was significantly reduced only 10 days following therapy (p<0.001). At any time after therapy, A. actinomycetemcomitans was not detected intraorally in 5 of 10 (50%) test and 1 of 13 (8%) control patients harboring this pathogen at baseline; P. gingivalis was not detected in only 1 of 18 (6%) test and none of the 17 control patients harboring this pathogen at baseline. Although the data indicated that the assessed antimicrobial therapy may suppress A. actinomycetemcomitans from the entire oral cavity below detectable levels over a minimum of 12 months, P. gingivalis persisted or reoccurred.

Long-term maintenance of alveolar bone gain after implantation of autolyzed, antigen-extracted, allogenic bone in periodontal intraosseous defects

This randomized controlled trial assessed the long-term maintenance of alveolar bone gain after implantation of autolyzed, antigen-extracted, allogenic (AAA) bone. AAA bone is a demineralized freeze-dried bone allograft processed after previously described methods. In each of 14 patients, AAA bone was implanted into the intraosseous defect of 1 tooth (test); a second tooth with an intraosseous defect was treated by modified Widman flap surgery alone (control). All patients were offered supportive periodontal therapy at 3- to 6-month intervals following treatment. Clinical measurements were taken prior to surgery, 6 months, and 3 years following surgery. Of the 14 patients enrolled, 11 patients completed the 6-month and 8 patients the 3-year examination. In test teeth, bone gain was significantly greater compared to control teeth at 6 months (2.2+/-0.5 mm and 1.2+/-0.5 mm, respectively) and 3 years (2.3+/-0.7 mm and 1.1+/-0.8 mm, respectively) (P < 0.05). Also, more probing attachment was gained in test compared to control teeth at 3 years (2.0+/-0.7 mm and 0.8+/-0.5 mm, respectively; P < 0.05). At 3 years, Porphyromonas gingivalis was detected in 3 test and 2 control teeth by polymerase chain reaction, whereas no Actinobacillus actinomycetemcomitans was found. Due to the low detection frequency, there was no clear correlation between the maintenance of alveolar bone during supportive periodontal therapy and subgingival infection with P. gingivalis. The data indicated that alveolar bone gain after implantation of AAA bone may be maintained over a minimum of 3 years in patients receiving periodontal supportive therapy.

Eradication of Actinobacillus actinomycetemcomitans from the oral cavity in adult periodontitis

Eradication of Actinobacillus actinomycetemcomitans from the oral cavity seems to be a prerequisite for successful therapeutic outcome in patients periodontally infected with the organism. In view of the limited number of subgingival samples obtained in recent studies one cannot conclude, however, whether eradication has actually been achieved. In the present study clinical and microbiological parameters were monitored in 10 adult patients with A. actinomycetemcomitans-associated periodontitis during successive non-surgical and adjunctive metronidazole plus amoxicillin (or ciprofloxacin) (AB) therapy. In every patient, 13 extracrevicular samples and subgingival samples from the deepest site of every tooth present were selectively cultivated for A. actinomycetemcomitans. The organism was isolated in 47 +/- 29% subgingival and 64 +/- 31% extracrevicular samples. Six weeks following subgingival scaling, A. actinomycetemcomitans was detected in 37 +/- 30% subgingival and 55 +/- 38% extracrevicular samples (n.s.). Three months after antibiotic therapy, the organism was recovered from only 1 patient. At baseline, 7.5 +/- 4.2% sites had a probing pocket depth (PPD) > or = 7 mm. This proportion dropped to 2.3 +/- 2.4% after scaling (p < 0.05) and to 0.3 +/- 0.4% after AB (p < 0.05). The proportion of sites with clinical attachment loss (CAL) > or = 6 mm dropped from 23.3 +/- 13.3% to 17.7 +/- 13.4% (p < 0.05) and to 16.8 +/- 14.6%. Statistical analysis revealed that the organism was strongly related, at baseline, to PPD > or = 7 mm (odds ratio 9.8, p < 0.001). Six weeks after scaling, the organism was associated with CAL > or = 6 mm (odds ratio 1.8, p = 0.02). After scaling, high counts of A. actinomycetemcomitans in excess of 10(4) CFU/ml significantly interfered with attachment gain of > or = 2 mm (odds ratio 0.24, p = 0.001). Based on the present findings, eradication of A. actinomycetemcomitans seems to be possible with adjunctive antibiotic treatment. Elimination of the organism after scaling was only weakly associated with clinical improvement.

Microbial ecology of Actinobacillus actinomycetemcomitans, Eikenella corrodens and Capnocytophaga spp. in adult periodontitis

Information on intraoral distribution of putative periodontal pathogens might be essential for controlling different forms of periodontal disease. Colonization may be either promoted or impeded by other bacteria competing in the subgingival ecosystem. In recent investigations microbial associations between dental organisms have been determined in a multitude of subgingival plaque samples within multiple patients and described by odds ratios, in most circumstances without taking into account the correlated structure of the observations within a single individual. The present investigation had 3 major objectives: (i) to describe the intraoral distribution of some facultatively anaerobic, Gram-negative rods, i.e. Actinobacillus actinomycetemcomitans, Eikenella corrodens-like organisms and Capnocytophaga spp., in a multitude of subgingival and extracrevicular samples of 10 adult subjects with A. actinomycetemcomitans-associated periodontitis; (ii) to analyse possible inconsistencies of microbial associations between these periodontal organisms; and (iii) to determine factors increasing the likelihood of isolating these bacteria in a given subgingival site by employing Generalized Estimation Equation (GEE) methods. Clinical examinations were carried out at 6 sites of every tooth present. In each subject, 13 extracrevicular (2 cheek mucosa, 3 tongue, 4 gingival, 2 tonsillar samples, 1 palatinal, 1 saliva sample) and between 22 and 44 subgingival samples from deepest sites of every tooth present (n = 296) were selectively cultivated for A. actinomycetemcomitans, E. corrodens and Capnocytophaga spp. In extracrevicular material, A. actinomycetemcomitans, Capnocytophaga spp. and E. corrodens were isolated in 9, 10 and 6 patients, and from 65, 82 and 15% samples, respectively. The organisms were recovered from 51, 62 and 27% subgingival plaque samples, respectively. Heterogeneity tests did not reveal significant inconsistencies of microbial associations between bacteria in subgingival plaque. Mantel-Haenszel's odds ratios ranged between 2.0 for A. actinomycetemcomitans and Capnocytophaga spp. and 18.7 for Capnocytophaga spp. and E. corrodens. An exchangeable working dependence structure was employed in the GEE approach. The odds of isolating A. actinomycetemcomitans was increased by factor 3.7 in 4-6 mm deep pockets, and 9.5 in > or = 7 mm deep pockets. The odds of presence of E. corrodens was increased by factor 10.8 in the case of presence of Capnocytophaga spp. and 2.1 in the case of presence of A. actinomycetemcomitans. Capnocytophaga spp. were associated with bleeding on probing and molar sites. Presence of E. corrodens was associated with clinical attachment loss but not periodontal probing depth. Results of the present study indicated an association of A. actinomycetemcomitans with periodontal pathology. Whereas this organism and Capnocytophagae were widely distributed in extracrevicular ecosystems of the mouth, E. corrodens only occasionally appeared in saliva or on mucous membranes of the oral cavity. In general, GEE methods seem to allow to determine factors associated with the presence of periodontal organisms in a multivariate approach and considering the correlated structure of the data.

Multiplex PCR using conserved and species-specific 16S rRNA gene primers for simultaneous detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis

Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis are strongly associated with periodontitis. However, little is known about their distribution in periodontally healthy individuals, because culturing techniques are not sufficiently sensitive. A modified multiplex PCR was developed to address that question. Our method uses two species-specific forward primers in combination with a single reverse primer. These primers target variable and conserved regions of the 16S rRNA gene. Sensitivity was determined by testing serial dilutions of A. actinomycetemcomitans and P. gingivalis cells. Primer specificity was tested against (i) six A. actinomycetemcomitans strains and four P. gingivalis strains, (ii) seven different species of oral bacteria, and (iii) supra- and subgingival plaque from 20 subjects. The multiplex PCR had a lower limit of detection of 2 A. actinomycetemcomitans and 30 P. gingivalis cells. Species-specific amplicons were obtained for all A. actinomycetemcomitans and P. gingivalis strains tested and did not occur with seven other bacterial species unless A. actinomycetemcomitans and P. gingivalis were added. Neither target species was detected in supragingival plaque; A. actinomycetemcomitans was detected in one subgingival specimen, and P. gingivalis was detected in another. When plaque samples were spiked with 10 A. actinomycetemcomitans cells and 100 P. gingivalis cells, species-specific amplicons were detected. These findings show our multiplex PCR to be highly sensitive and specific while allowing simultaneous detection of A. actinomycetemcomitans and P. gingivalis. This assay has potential applications in epidemiological studies, diagnosis, treatment planning, and monitoring of periodontal pathogens.

Specific antibody reactivity against a 110-kilodalton Actinobacillus actinomycetemcomitans protein in subjects with periodontitis

The purpose of the present study was to determine the serum immunoglobulin A (IgA), IgM, and IgG reactivities against proteins of Actinobacillus actinomycetemcomitans in patients with periodontitis. Serum samples from 20 patients with early-onset periodontitis, 20 patients with adult periodontitis, and 20 age- and sex-matched healthy controls were assessed by immunoblot analysis. IgG antibody reactivity against a sarcosyl-insoluble 110-kDa protein of A. actinomycetemcomitans was detected in 65 and 45% of patients with early-onset periodontitis and adult peritonitis, respectively, and IgA antibodies against this protein were found in 70 and 55% of these patients, respectively. However, control subjects showed no IgG reactivity, and IgA antibodies against the sarcosyl-insoluble 110-kDa protein were detected in only 5% of the patients (P < 0.05). There was no IgM antibody reactivity against this protein in any of the diseased or healthy subjects. The sensitivity and specificity of serum IgA antibody reactivity against the 110-kDa protein in detecting subgingival A. actinomycetemcomitans infection, as determined by PCR, were 77 and 66%, respectively. The results of the study indicated that the sarcosyl-insoluble 110-kDa protein is a potential candidate for use in the serodiagnosis of periodontal disease.