Variable serum immunoglobulin G immune response to genetically distinct Eikenella corrodens strains coexisting in the human oral cavity

This study examined the variable serum immunoglobulin G (IgG) levels to genetically distinct autologous Eikenella corrodens strains by enzyme-linked immunosorbent assay (ELISA). Twenty subjects, including 10 adult periodontitis patients, 5 juvenile periodontitis patients and 5 periodontally healthy subjects were examined. Each subject was colonized by 2-8 genetically distinct E. corrodens strains. The serum IgG levels to autologous E. corrodens within individuals were significantly different in 7 adult periodontitis patients, 4 juvenile periodontitis patients and a periodontally healthy subject. Poor correlation was found in diseased subjects between serum IgG levels to autologous strains and to reference strains ATCC 23834 or FDC 373. Four adult periodontitis patients and two juvenile periodontitis patients exhibited significant serum IgG levels to autologous E. corrodens strains (two standard deviations above the mean for periodontally healthy subjects); two of these six diseased subjects exhibited low serum IgG levels to reference strains and would have been classified as low immune responders if only reference strains had been used in ELISA. This study showed the importance of using autologous E. corrodens strains in the assessment of serum IgG immune responses to this organism.     

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 ≥ 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. actinomycetemcoinitans with periodontal pathology. Whereas this organism and Capizocytopliagae 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.     

Killing of oral, gram-negative, facultative bacteria by the rabbit defensin, NP-1

Oral, gram-negative, facultative bacteria, including Actinobacillus actinomycetemcomitans, Eikenella corrodens, and Capnocytophaga spp. have been associated with destructive periodontal infection. Neutrophils play a critical role in defending the periodontium against destructive infection. Defensins are antimicrobial peptides that have been isolated in human, rabbit, guinea pig, and rat leukocytes that may constitute an important nonoxidative mechanism of killing. The purpose of this study was to examine the sensitivity of a battery of oral, gram-negative, facultative bacteria to the bactericidal effects of the isolated rabbit peptide NP-1. All species tested were killed by NP-1; however, there was strain-to-strain variation in sensitivity. The bactericidal effect was not dependent on net bacterial growth, although metabolic activity was evident as assessed by bacterial oxygen consumption. We conclude that bacteria are sensitive to the cidal mechanism involved in defensin-mediated bacterial killing and that the conditions of this assay system support the killing of bacteria by the defensin peptides.     

Associations between Porphyromonas gingivalis and oral treponemes in subgingival plaque

Colonization and/or proliferation of Treponema denticola may depend on the presence of Porphyromonas gingivalis . The aims of this study were to confirm this synergistic relationship, to determine whether other oral bacteria were similarly associated with P. gingivalis and to relate coinfection to the periodontal status of plaque donors. Subgingival plaque was collected from every tooth except third molars in 106 subjects who were grouped by their worst periodontal condition. In addition to P. gingivalis , monoclonal antibodies were used to identify Campylobacter rectus, Eikenella corrodens, T. denticola, Treponema socranskii and pathogen-related oral spirochetes. Associations of these bacteria with coinfection by P. gingivalis were assessed by estimated odds ratios. The results indicate that coinfection with P. gingivalis is linked to all tested bacteria, but each pair was associated with distinct periodontal conditions. The distribution of coinfected sites suggests biased colonization of facial surfaces over lingual surfaces.     

DNA probe detection of Eikenella corrodens, Wolinella recta and Fusobacterium nucleatum in subgingival plaque

This cross-sectional study used species-specific DNA probes to examine subgingival plaque specimens for the presence of Eikenella corrodens, Wolinella recta, and Fusobacterium nucleatum in adults with untreated periodontitis or gingivitis and in healthy controls. W. recta and F. nucleatum were more prevalent in diseased sites from the periodontitis group when compared with the controls (81% vs 22% and 83% vs 20% respectively). E. corrodens was detected in 62% of the control sites and 81% of the periodontitis sites. Because the control sites commonly contained this organism, E. corrodens may not be useful in differentiating between health and disease. In addition, the relationship between the prevalence of W. recta and F. nucleatum and the prevalence of the established periodontal pathogens, Actinobacillus actinomycetemcomitans, Bacteroides intermedius and Bacteroides gingivalis, was examined. Positive detection of W. recta and F. nucleatum correlated closely with the presence of A. actinomycetemcomitans, B. intermedius and B. gingivalis. Therefore, W. recta and F. nucleatum do not appear to be unique indicators of periodontal disease.     

Code blue: Acinetobacter baumannii,a nosocomial pathogen with a role in the oral cavity

Actinetobacter baumannii is an important nosocomial pathogen that can cause a wide range of serious conditions including pneumonia, meningitis, necrotizing fasciitis and sepsis. It is also a major cause of wound infections in military personnel injured during the conflicts in Afghanistan and Iraq, leading to its popular nickname of ‘Iraqibacter’. Contributing to its success in clinical settings is resistance to environmental stresses such as desiccation and disinfectants. Moreover, in recent years there has been a dramatic increase in the number of A. baumannii strains with resistance to multiple antibiotic classes. Acinetobacter baumannii is an inhabitant of oral biofilms, which can act as a reservoir for pneumonia and chronic obstructive pulmonary disease. Subgingival colonization by A. baumannii increases the risk of refractory periodontitis. Pathogenesis of the organism involves adherence, biofilm formation and iron acquisition. In addition, A. baumannii can induce apoptotic cell death in epithelial cells and kill hyphal forms of Candida albicans. Virulence factors that have been identified include pili, the outer membrane protein OmpA, phospholipases and extracellular polysaccharide. Acinetobacter baumannii can sense blue light through a blue‐light sensing using flavin (BLUF) domain protein, BlsA. The resulting conformational change in BlsA leads to changes in gene expression, including virulence genes.     

DNA probe detection of periodontal pathogens in HIV-associated periodontal lesions

Recent studies have shown that an atypical gingivitis and a rapidly progressive periodontal disease may be early-occurring opportunistic infections associated with human immunodeficiency virus (HIV) infection. This study examined the prevalence of selected periodontal pathogens associated with these HIV-related periodontal lesions. Subgingival plaque samples were obtained from both HIV-seronegative and HIV-seropositive homosexual men and from presumably uninfected heterosexual men. DNA probes were used to detect Actinobacillus actinomycetemcomitans, Bacteroides intermedius, Bacteroides gingivalis, Eikenella corrodens and Wolinella recta in the plaque. The healthy sites in both the seronegative and seropositive homosexual groups showed a greater prevalence of all test bacteria, except for E. corrodens, than did the heterosexual group. HIV-associated periodontitis sites showed a microbial profile qualitatively similar to that of conventional periodontitis, except that B. gingivalis was more prevalent in conventional periodontitis. In contrast, HIV-associated gingivitis sites exhibited a greater prevalence of all bacteria tested than conventional gingivitis sites. In fact, HIV gingivitis generally showed a bacterial profile similar to that of the HIV periodontitis lesions, except that W. recta was significantly more prevalent in HIV periodontitis. These data suggest that the HIV gingivitis lesion is a precursor to HIV periodontitis. Thus, early identification and prophylactic treatment of high-risk individuals may prevent the destruction of periodontal tissues.     

Functional aspects of the human salivary cystatins in the oral environment

OBJECTIVES: The aim of this study was to investigate the cysteine protease inhibitory properties of the human salivary cystatins S, SA and SN in order to identify potential in vivo target cysteine proteases which may include those involved in periodontal tissue destruction. In addition, the potential role of the salivary cystatins with respect to the tooth mineral balance and pellicle formation was also investigated.METHODS: Salivary cystatins S major, S minor, SA, SAT (a truncated form of SA) and SN were purified from human submandibular sublingual saliva. Sensitive fluorometric assays were used to test the inhibitory action of each purified form of salivary cystatin against a variety of cysteine proteases and to determine whether pH affected their inhibitory activity towards the well-characterized cysteine protease papain. Their potential role in the mineral balance of the tooth was assessed by the measurement of calcium binding and the rate of binding to carbonated apatite (CAP). RESULTS AND CONCLUSIONS: Salivary cystatin SN was found to inhibit the human lysosomal cathepsins B, H and L and salivary cystatin SA was found to inhibit human lysosomal cathepsin L in vitro. These proteases are involved in periodontal tissue destruction and these data suggest that salivary cystatins SA and SN are involved in the control of the proteolytic events in vivo. Salivary cystatin S was not an inhibitor of the cysteine proteases tested suggesting that its primary role is not as a cysteine protease inhibitor. However, S was able to bind more calcium and bind more rapidly to CAP than SA or SN, suggesting that its primary role in the oral environment is likely to be the involvement with the mineral balance of the tooth.     

寡发酵链球菌分子标识鉴定方法的建立

目的建立快速、有效鉴定寡发酵链球菌的方法，并验证其准确性。方法以9种口腔链球菌11株标准菌株的DNA为模板，用寡发酵链球菌16S rDNA的特异引物和乳酸氧化酶基因的引物通过PCR分别扩增这两个基因的部分片段，建立用分子标识鉴定该菌的方法。并从9个无龋的志愿者口腔中取得集合牙菌斑，在加红霉素的轻唾琼脂平板中进行培养，分离到疑似寡发酵链球菌的菌落后，用已建立的方法进行鉴定。并对初步鉴定为寡发酵链球菌的分离株进行16S rDNA序列同源性分析，以确定鉴定的准确性。结果用建立的分子标识鉴定方法，发现在11株标准菌株中只有3株寡发酵链球菌有扩增产物；用该方法鉴定为寡发酵链球菌的来自无龋志愿者牙菌斑的分离株，经16S rDNA序列同源性分析证实确实为寡发酵链球菌。结论用寡发酵链球菌16S rDNA特异性引物和乳酸氧化酶基因引物进行两步PCR来鉴定寡发酵链球菌是准确、可靠的。     

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. actinomyceterncomitans 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) ≥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) ≥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 ≥7 mm (odds ratio 9.8, p<0.001). Six weeks after scaling, the organism was associated with CAL ≥6mm (odds ratio 1.8, p = 0.02). After scaling, high counts of A. actinomycetemcomitans in excess of 10⁴ CFU/ml significantly interfered with attachment gain of ≥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.     

High prevalence of human papillomaviruses in the normal oral cavity of adults

Human papillomavirus (HPV) infection in the normal oral cavity was studied by the sensitive polymerase chain reaction (PCR) using primers for the L1 region of human papillomavirus DNA and high fidelity amplification system. Cells were scraped from the oral mucosae of 7 (mean age; 42 years) and 30 (mean age; 32 years) volunteers with and without skin warts, respectively. Human papillomavirus DNA was detected in 30/37 (81.1%) specimens and their copy numbers per cell were 10(-1) to 10(-4) (mean, 10(-3)). The human papillomavirus types determined by PCR-based sequencing analysis were HPV-18 (26/30; 86.7%), -61 (18/30; 60%), -59 (7/30; 23.3%), -16 (2/30; 6.7%), -6 (1/30; 3.3%) and an unknown type (HPV-X71) (1/30; 3.3%). Multiple human papillomavirus types were present in 17/30 (56.7%) specimens. HPV-6 was detected in 2 of 7 skin warts and differed from the human papillomavirus types of the corresponding oral specimens. These data suggest that human papillomavirus infection in the oral mucosa occurs much more frequently than previously considered.     

Distribution and forms of iodine in human oral cavity

Neither iodinated proteins nor iodinated. low-molecular weight compounds (e.g. iodinated tyrosine derivatives) could be detected in concentrated human salivary supernatant by using the Ce(SO₄)₂-method either directly or after thin-layer chromatography. Salivary sediment contained free 1^? ions, loosely bound iodine (released with saline) and strongly bound iodine (released with sonication, detergent and acid hydrolysis). A positive correlation between salivary and crevicuiar excretion of l^? from plasma was observed. Thiocyanate ions, which competitively inhibit peroxidase-catalysed oxidation and iodination reactions and which are abundant in human saliva, possibly prevent the coupling of l^? to protein in vivo although some human salivary proteins are very susceptible to iodination in vitro.     

Distribution of periodontal disease in a Swedish adult population 1973, 1983 and 1993

Abstract. The aim of this study was to compare changes in periodontal status in a Swedish poplation over a period of 20 years. Cross-sectional studies were carried out in Jönköping County in 1973, 1983, and 1993. Individuals were randomly selected from the following age groups: 20, 30, 40, 50, 60, and 70 years. A total of 600 individuals were examined in 1973, 597 in 1983, and 584 in 1993. The number of dentate individuals was 537 in 1973, 550 in 1983, and 552 in 1993. Based on clinical data and full mouth intra-oral radiographs, all individuals were classified into 5 groups according to the severity of the periodontal disease experience. Individuals were classified as having a healthy periodontium (group 1). gingivitis without signs of alveolar bone loss (group 2), moderate alveolar bone loss not exceeding 1/3 of the normal alveolar bone height (group 3), severe alveolar bone loss ranging between 1/3 and 2/3 of the normal alveolar bone height (group 4), or alveolar bone loss exceeding 2/3 of the normal bone height and angular bony defects and/or furcation defects (group 5). During these 20 years, the number of individuals in groups 1 and 2 increased from 49%. in 1973 to 60% in 1993. In addition, there was a decrease in the number of individuals in group 3, the group with moderate periodontal bone loss. Groups 4 and 5 comprised 13% of the population and showed no change in general between 1983 and 1993. The individuals comprising these groups in 1993, however, had more teeth than those who comprised these groups in 1983; on the average, the individuals in disease group 4 had 4 more teeth and those in disease group 5, 2 more teeth per subject. ID 1973, these 2 groups were considerably smaller, probably because of wider indications for tooth extractions and fewer possibilities for periodontal care which meant that many of these individuals had become edentulous and were not placed in a group. Individuals in groups 3, 4, and 5 were subdivided according to the number of surfaces (%) with gingivitis and periodontal pockets (≥4 mm). In 1993, 20%, 42%, and 67% of the individuals m groups 3, 4, and 5 respectively were classified as diseased and in need of periodontal therapy with >20% bleeding sites and >10% sites with periodontal pockets ≥4 mm. In conclusion, an increase in the number of individuals with no marginal bone loss and a decrease in the number of individuals with moderate alveolar bone loss can be seen. The prevalence of individuals in the severe periodontal disease groups (4, 5) was unchanged during the last 10 years; however, the number of teeth per subject increased.     

Periodontal conditions in adults, 35–44 years of age: an overview of CPITN data in the WHO Global Oral Data Bank

Results of 28 CPITN surveys in 24 countries for the age group 35-44 years, stored in the WHO Global Oral Data Bank as of 1 July 1986 are assembled in an overview presenting: percentages of persons according to the highest score for each person, the estimated national percentages of edentulousness and the mean numbers of sextants affected per person. It is concluded that for a large majority in most of the populations observed, the progress of periodontal disease has been slow and seems to be compatible with retention of a natural dentition until at least the age of 50.     

Leukocytoclastic vasculitis (anaphylactoid purpura): a unique occurrence in the oral cavity.

Leukocytoclastic vasculitis, immune complex disorder (type III), is a skin disease with both an acute form characterized by bullae, vesicles and ulcerations, and a chronic form characterized by petechiae, macules and ulcerations. The disease presents certain systemic features including diffuse or focal glomerulonephritis and renal failure. The histopathologic characteristics of leukocytoclastic vasculitis in the skin appear primarily in small blood vessels and consist of an infiltration of inflammatory cells, leukoclasis, swelling of endothelial cells, occlusion of blood vessels, accumulation of fibrin and fibrinoid degeneration, as well as the presence of immune complexes in and around blood vessel walls. Although leukocytoclastic vasculitis is described as several diseases which can spread systemically, including the gastrointestinal tract and the kidneys, the manifestations of the disease in the oral cavity have not yet been reported. The present paper reports unique oral lesions in a 38-yr-old woman, diagnosed as leukocytoclastic vasculitis, without any accompanying skin or systemic lesions.     

The association of periodontal disease with oral malodour in a Japanese population

Oral Diseases (2010) 16 , 702–706 Aim: The purpose of this study was to evaluate the association between oral malodour and periodontal disease, and to determine the effect of periodontal therapy on oral malodour. Materials and Methods: Oral malodour parameters, including volatile sulphur compound (VCS) measurement, methyl mercaptan/hydrogen sulphide ratio by gas chromatography, organoleptic testing, tongue coating score, and periodontal parameters were evaluated in 823 patients complaining of oral malodour. Amongst these patients, 89 with oral pathogenic halitosis received tongue cleaning and periodontal therapy. Oral malodour and periodontal parameters were measured at baseline and after treatment. Results: Amongst 823 patients, 102 were diagnosed with gingivitis and 721 with periodontitis. VCS levels and periodontal parameters increased according to the severity of oral malodour. Organoleptic testing significantly correlated with periodontal probing depth and a percentage of periodontal pocket depth ≥4 mm (r = 0.40 and 0.39 respectively). There were significant correlations between methyl mercaptan/hydrogen sulphide ratio and periodontal parameters. Significant decrease in oral malodour and periodontal parameters in 89 patients with oral pathogenic halitosis was also observed after periodontal treatment. Conclusions: Oral malodour is associated with periodontal disease, and periodontal therapy combined with tongue cleaning is beneficial for oral pathogenic halitosis.     

Genetic heterogeneity in Prevotella intermedia, Prevotella nigrescens, Prevotella corporis and related species isolated from oral and nonoral sites

Prevotella intermedia (43 isolates), Prevotella nigrescens (55) and Prevotella corporis (8) from oral and nonoral sites were distinguished by species-specific DNA fragments, after hybridization of DNA fragments with ribosomal RNA (ribotyping). Eight strains previously identified as P. intermedia did not have these specific fragments. P. nigrescens, P. intermedia and P. corporis formed separate clusters in dendrograms constructed using clustering with an unweighted pair group method with arithmetic averages of similarity values derived from ribotype patterns, with 10 subclusters in P. intermedia isolates and 26 in P. nigrescens. Nine groups of P. intermedia isolates and 6 of P. nigrescens shared identical patterns. Specific ribotypes or species were not associated with particular diseases when all isolates were analyzed. However, results from organisms isolated by one laboratory using consistent clinical reporting indicated that P. intermedia was associated with more severe forms of periodontitis and P. nigrescens with mild to moderate disease.     

Effects of oral hygiene on periodontal tissues in a town in Yugoslavia

Abstract We examined 1316 pupils, average age 16.6 years, in a small town in Serbia. The purpose of this study was to find out the effects of the oral hygiene on the condition of the periodontal tissues and the frequency of gingivitis and periodontal disease and their severity in this age group. The presence and quantity of dental plaque were registered according to the Silness & Löe Plaque Index. The amount of dental calculus was determined according to the Greene & Vermillion method. The condition of periodontal tissues was evaluated by Ramfjord's method. It was found that only 5.3% of the examined pupils had a clinically healthy periodontium. Gingivitis was discovered in 60.6%, and periodontal disease (with periodontal pockets) in 34.1% of the examined pupils. The average PDI was 1.8. We revealed great quantities of soil and hard deposits on the teeth of examined pupils. The average Plaque Index was very high (1.9).     

Distribution of Bacteroides forsythus genotypes in a Japanese periodontitis population

Bacteroides forsythus is an important pathogen in periodontal diseases and has been associated with advanced and refractory periodontitis. The difficulties associated with culturing this species have meant that the distribution and pathogenic mechanisms of B. forsythus remain unclear. In this study, the arbitrarily primed polymerase chain reaction (AP-PCR) method was used to investigate the genotype distribution of B. forsythus in a Japanese periodontitis population, as well as the relationship between AP-PCR genotypes and periodontal status. B. forsythus reference strain, ATCC 43037T and 137 clinical bacterial isolates from 64 subjects were separated into 11 distinct AP-PCR genotypes using a single randomly-sequenced primer, 5'-CCGGCGGCG-3' (A-05). The majority (80.9%) of B. forsythus strains examined belonged to AP-PCR genotypes I, II, III and IV (accounting for 39.7%, 20.6%, 10.3% and 10.3%, respectively). Types I and III primarily consisted of isolates from chronic periodontitis subjects (80.8% and 85.7%, respectively), while Types II and IV consisted mainly of isolates from aggressive periodontitis subjects (85.7% and 100%, respectively). Except for three subjects who harbored two different B. forsythus genotypes in the oral cavity, all subjects only infected with one genotype intraindividually. These results demonstrate that the AP-PCR method is useful for genotypic analysis of B. forsythus. This species showed a genetic diversity among the investigated population. A clonal nature of B. forsythus infection is suggested. Furthermore, different AP-PCR genotypes of B. forsythus appear to be associated with different types of periodontitis.