Clonality of Porphy givens intermedia and Preotella nigrescens isolated from periodontally diseased and healthy sites

Black-pigmented anaerobes have been implicated as major pathogens in the aetiology of adult periodontitis but these organisms are also found in healthy sites. This study aimed to examine the relationship between genotypes of black-pigmented anaerobes and disease status of periodontal sites using restriction endonuclease analysis (REA) and ribotyping. The main black-pigmented species recovered from sites were Pot phyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens . Each of the 58 subjects investigated harboured distinct genotypes of these three species. Most subjects appeared to be colonized by a single genotype of P. gingivalis and Pr. intermedia . whereas multiple types of Pr. nigrescens colonized many individuals. Plasmids were only found in a few Pr. nigrescens strains. No association was found between the disease status of sites and any specific or group of genotypes of either species or presence of a plasmid. Since the same genotypes of P. gingivalis, Pr. intermedia and Pr. nigrescens were found at both diseased and non-diseased sites in a subject, adult periodontitis is not explained by the presence of specially virulent clones of these organisms. Their role in periodontitis, therefore, is likely to be opportunistic.     

Isolation and genotyping of black-pigmented anaerobes from periodontal sites of HIV-positive and non-infected subjects in Thailand

BACKGROUND, AIMS: The aims of this study were to investigate the prevalence of periodontitis, the prevalence of black-pigmented anaerobes and the genotypes of Porphyromonas gingivalis and Prevotella intermedia present in HIV-infected and control subjects in a heterosexual Thai population. METHOD: 50 AIDS patients and 50 control subjects were included in the study. Their periodontal condition was examined by assessment of bleeding on probing, attachment loss and probing depth, and presence of erythema around 6 teeth (16, 21, 24, 36, 41, 44). Subgingival plaque was collected from the mesiobuccal sites of these teeth and was cultured anaerobically for black-pigmented bacteria. Species were characterised using biochemical profiles and total protein profiles. Genotyping of each isolate was performed using PCR techniques. RESULTS: There was little clinical evidence of HIV-associated periodontitis in the HIV-positive subjects and no difference was found in the prevalence or genotype distribution of black-pigmented anaerobes between HIV-infected and control subjects. CONCLUSIONS: These data suggest lack of severe periodontal destruction due to HIV-infection in Thailand and that these subjects are not colonised by more numerous or characteristic clones of certain putative periodontal pathogens.     

Distribution of the tetracycline resistance determinant tetQ gene in oral isolates of black-pigmented anaerobes in Japan

We investigated the distribution of tetracycline resistance determinant tetQ in oral black-pigmented anaerobes using a polymerase chain reaction (PCR) METHOD: A total of 185 healthy subjects were divided into 3 groups based on subject age: young (6 to 10 years, n=58), middle (11 to 40 years, n=96), and elder (exactly 70 years, n=31). The prevalence of black-pigmented anaerobes in the gingival sulcus among these groups was 29.3%, 28.2%, and 64.5%, respectively. The prevalence of Prevotella nigrescens among these groups was 22.4%, 15.6%, and 32.3%, respectively, whereas the prevalence of Prevotella intermedia was 1.7%, 4.2%, and 35.5%, respectively. Porphyromonas gingivalis was found only in the elder group (16.1%). The prevalence of the tetQ gene in the black-pigmented anaerobes-positive subjects was almost the same among the 3 groups (approximately 30%). The tetQ gene was found in 27.5% (46 of 167) of P. nigrescens isolates, whereas it was found in only 6.4% (3 of 47) of P. intermedia isolates and in none of the 19 P. gingivalis isolates. Restriction endonuclease digestion patterns of the PCR products revealed 83.6% of 49 tetQ-positive isolates were of subtype A2H2 (AluI type 2, HpaII type 2).     

Dipeptide utilization by the periodontal pathogens Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum

Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum, which can frequently be isolated from periodontal pockets, preferentially utilize proteins and peptides as growth substrates. In this study, we determined the size of peptide that is preferentially utilized as a source of energy and material for cell growth by P. gingivalis, P. intermedia, P. nigrescens and F. nucleatum using various sizes of poly amino acids consisting of two to approximately 100 molecules of aspartate or glutamate. Resting cells of P. gingivalis, P. intermedia and P. nigrescens utilized aspartylaspartate, while cells of P. gingivalis and F. nucleatum utilized glutamylglutamate. The addition of aspartylaspartate to the culture medium increased the growth of P. gingivalis, P. intermedia and P. nigrescens, while the addition of glutamylglutamate promoted the growth of P. gingivalis and F. nucleatum. These results clearly indicate that dipeptides such as aspartylaspartate and glutamylglutamate can be utilized as growth substrates for P. gingivalis, P. intermedia, P. nigrescens and F. nucleatum.     

Invasive differences among Porphyromonas gingivalis strains from healthy and diseased periodontal sites

Background and Objective:  The purpose of this study was to determine any difference between Porphyromonas gingivalis isolates from periodontally healthy sites as compared to those from diseased sites with respect to the ability to invade host cells.
Material and Methods:  Subgingival plaque samples were obtained from periodontally healthy and diseased sites using paper points. P .  gingivalis colonies were isolated and tested, using an antibiotic protection assay, for their ability to invade KB cells. P. gingivalis 381 and Escherichia coli MC1061 were used as controls.
Results:  Mean values of 16.79 ± 0.86 × 10³ colony-forming units/mL and 26.14 ± 2.11 × 10³ colony-forming units/mL were observed in invasion assays for isolates from periodontally healthy and diseased sites, respectively. P .  gingivalis present in diseased sites had significantly greater invasive abilities than strains isolated from healthy sites. No statistical difference was noted between male or female subjects concerning the degree of invasion; isolates from diseased sites from both genders had significantly greater invasion abilities than those from healthy sites. A significant correlation was found between the increased invasive capabilities of P .  gingivalis isolates vs. an increased probing depth.
Conclusion:  The increased invasion noted with P .  gingivalis isolates from diseased sites vs. healthy sites, and the increased invasive capabilities with increasing probing depth, indicate that P .  gingivalis isolates have a varying ability to invade host cells in the periodontal pocket.     

Improvement of periodontal status by green tea catechin using a local delivery system: a clinical pilot study

The purpose of this study was to determine the usefulness of green tea catechin for the improvement of periodontal disease. The minimum inhibitory concentration (MIC) and bactericidal activity of green tea catechin against black-pigmented, Gram-negative anaerobic rods (BPR) were measured. Hydroxypropylcellulose strips containing green tea catechin as a slow release local delivery system were applied in pockets in patients once a week for 8 weeks. The clinical, enzymatic and microbiological effects of the catechin were determined. Green tea catechin showed a bactericidal effect against Porphyromonas gingivalis and Prevotella spp. in vitro with an MIC of 1.0 mg/ml. In the in vivo experiment, the pocket depth (PD) and the proportion of BPR were markedly decreased in the catechin group with mechanical treatment at week 8 compared with the baseline with significant difference. In contrast, PD and BPR were similar to the baseline and the value at the end of the experimental period in the placebo sites of scaled groups. The peptidase activities in the gingival fluid were maintained at lower levels during the experimental period in the test sites, while it reached 70% of that at baseline in the placebo sites. No morbidity was observed in the placebo and catechin groups without mechanical treatment. Green tea catechin showed a bactericidal effect against BPR and the combined use of mechanical treatment and the application of green tea catechin using a slow release local delivery system was effective in improving periodontal status.     

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.     

Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia and Prevotella nigrescens in endodontic lesions detected by culture and by PCR

he aim of this study was to investigate the presence of four black-pigmented bacteria, Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia and Prevotella nigrescens, in endodontic infections by culture and polymerase chain reaction (PCR) analyses. Microbial samples were obtained from 50 teeth with untreated necrotic pulps (primary infection) and from 50 teeth with failing endodontic treatment (secondary infection). Microbiological strict anaerobic techniques were used for serial dilution, plating, incubation, and identification. For PCR detection, the samples were analyzed using species-specific primers of 16S rDNA and the downstream intergenic spacer region. Culture and PCR detected the test species in 13/100 and 50/100 of the study teeth, respectively. The organisms were cultured from 11/50 (22%) of primarily infected root canal samples and from 2/50 (4%) of secondary root canal samples. PCR detection identified the target species in 32/50 (64%) and 18/50 (36%) of primary and secondary infections, respectively. P. gingivalis was rarely isolated by culture methods (1%), but was the most frequently identified test species by PCR (38%). Similarly, P. endodontalis was not recovered by culture from any tooth studied, but was detected by PCR in 25% of the sampled teeth. PCR-based identification also showed higher detection rates of P. intermedia (33%) and P. nigrescens (22%) than culture (13%). In conclusion, P. gingivalis, P. endodontalis, P. intermedia, and P. nigrescens were identified more frequently in teeth with necrotic pulp than in teeth with failing endodontic treatment. Also, a higher frequency of black-pigmented species was detected by PCR than by culture.     

实时荧光定量PCR法检测治疗后龈下菌斑中优势菌的变化

目的：运用实时荧光定量PCR(qRT-PCR)技术检测慢性牙周炎患者治疗前、后龈下菌斑中牙龈卟啉单胞菌(Pg)和中间普氏菌(Pi)的拷贝数,以了解qRT-PCR对2种牙周致病菌检测的敏感性和牙周治疗的疗效。方法：选取62例中、重度牙周炎患者,分别采用龈下刮治、牙周袋内盐酸米诺环素软膏(派丽奥)给药和两者综合治疗,采集治疗前、后(7d)龈下菌斑,提取细菌基因组DNA,合成针对Pg和Pi的16S rRNA基因的特异引物,运用qRT-PCR法检测Pg和Pi的拷贝数。采用SAS 9.1.3软件包对数据进行Kruskal-Wallis和 Wilcoxon 秩和检验。结果：Pg、Pi在不同样品组中检测到的绝对拷贝数数量分别为103～106和102～106,在慢性牙周炎患者龈下菌斑中的检出率和绝对拷贝数量显著高于健康对照组(P<0.05);3组治疗后的Pg数量比治疗前下降,其中综合治疗组和派丽奥治疗组下降率显著高于龈下刮治组。Pi的数量在派丽奥治疗组和龈下刮治组治疗后无显著减少,但在综合治疗组显著下降(P<0.05)。结论：qRT-PCR法能快速鉴定和精确定量Pg和Pi;综合治疗法比单一疗法能更有效抑制Pg和Pi。     

Lipopolysaccharides from periodontal pathogens prime neutrophils for enhanced respiratory burst: differential effect of a synthetic lipid a Precursor IVA(LA-14-PP)

When neutrophils are incubated with bacterial lipopolysaccharide (LPS), they become primed for enhanced release of superoxide anion (O₂⁻) in response to stimulation by FMLP. We investigated the human neutrophil-priming activity of LPS from the periodontal pathogens, Porphyromonas gingivalis (Pg) , Prevotella intermedia (Pi) and Actinobacillus actinomycetemcomitans (Aa) in comparison with that of LPS from Escherichia coli (E. coli) . The optimum conditions for LPS to prime neutrophils were assessed for every LPS and found to be as follows: Neutrophils were incubated with LPS in the presence of 10% heat-inactivated plasma and 1 mM EDTA at 37°C for 30 min and then stimulated with 1 μM FMLP at 37°C for 7 min. Under these conditions, half-maximum priming was observed at 6.2 ng/ml Pg -LPS, 45 ng/ml Pi -LPS, 1.5 ng/ml Aa -LPS and 1.5 ng/ ml E. coli -LPS. The priming activity of each LPS was neutralized by polymyxin B. Anti-CD14 monoclonal antibody inhibited priming by all LPS. The priming by Aa -LPS and E. coli -LPS was inhibited by LA-14-PP, a synthetic lipid A precursor IV_A, but that by Pg -LPS and Pi -LPS was not. Priming by tumor necrosis factor alpha was not affected by polymyxin B, anti-CD14 antibody or LA-14-PP. Gelation of Limulus amebocyte lysate occured at 10 pg/ml Pg -LPS, 30 pg/ml Pi -LPS, 3 pg/ml Aa -LPS and 3 pg/ml E. coli -LPS. Thus LPS from different periodontal pathogens primed neutrophils with different efficacy. The difference in the sensitivity to LA-14-PP among the four LPS tested raises the possibility that the mechanism of host response to Pg -LPS or Pi -LPS may be different from that to Aa -LPS or E . coli -LPS.     

Pathogenicity of Prevotella intermedia and Prevotella nigrescens isolates in a wound chamber model in rabbits

The pathogenicity of 14 isolates identified as Prevotella intermedia or Prevotella nigrescens by serogrouping using monoclonal antibodies was compared in a tissue cage model in rabbits. Seven strains from periodontal abscesses, 5 strains from deep periodontal pockets and 2 strains from gingivitis were tested in the animal model comprising 6 Teflon tissue cages implanted on the back each of 34 rabbits. A total of 105–108 cells of P. intermedia or P. nigrescens strains were inoculated alone or together with either Actinobacillus actinomycetemcomitans or Streptococcus mitis. Five strains of Porphyromonas gingivalis were used as a reference. The infectivity was recorded as pus formation and log viable count in aspirated material for 3, 7 and 14 days. None of the Prevotella strains inoculated in monoculture survived more than 3 days, and they had no capacity to produce abscess. P. intermedia or P. nigrescens strains in combination with A. actinomycetemcomitans produced abscesses in 33–100% and with S. mitis in 42–100%. No difference in abscess formation or log viable count in samples after 14 days was recorded between serogroup I ( P. intermedia ) and serogroup II and III ( P. nigrescens ). The infectivity of P. intermedia or P. nigrescens strains did not differ whether they were isolated from periodontal abscess, periodontal pocket or gingivitis. P. intermedia and P. nigrescens strains produced abscesses in combination with a facultative anaerobic strain and appears to have a similar pathogenicity in the wound chamber model in rabbits.     

Distribution of the tetracycline resistance determinant tetQ gene in oral isolates of black‐pigmented anaerobes in Japan

We investigated the distribution of tetracycline resistance determinant tetQ in oral black‐pigmented anaerobes using a polymerase chain reaction (PCR) method. A total of 185 healthy subjects were divided into 3 groups based on subject age: young (6 to 10 years, n=58), middle (11 to 40 years, n=96), and elder (exactly 70 years, n=31). The prevalence of black‐pigmented anaerobes in the gingival sulcus among these groups was 29.3%, 28.2%, and 64.5%, respectively. The prevalence of Prevotella nigrescens among these groups was 22.4%, 15.6%, and 32.3%, respectively, whereas the prevalence of Prevotella intermedia was 1.7%, 4.2%, and 35.5%, respectively. Porphyromonas gingivalis was found only in the elder group (16.1%). The prevalence of the tetQ gene in the black‐pigmented anaerobes‐positive subjects was almost the same among the 3 groups (approximately 30%). The tetQ gene was found in 27.5% (46 of 167) of P. nigrescens isolates, whereas it was found in only 6.4% (3 of 47) of P. intermedia isolates and in none of the 19 P. gingivalis isolates. Restriction endonuclease digestion patterns of the PCR products revealed 83.6% of 49 tetQ‐positive isolates were of subtype A2H2 (AluI type 2, HpaII type 2).     

牙龈卟啉菌、中间普氏菌的分离、培养和鉴定

目的：采用厌氧培养和鉴定技术，分离牙周炎患者龈下菌斑中的牙龈卟啉菌和中间普氏菌。方法：采集牙周炎患者的龈下菌斑，厌氧培养，分离产黑色素菌。经长波长紫外灯观察，各种生化分析和间接免疫荧光染色，分离和鉴定牙龈卟啉菌，中间普氏菌。结果：在受检的33例牙周炎患者中，24例患者检出了牙龈卟啉菌，总检出率为72．77％，共分离了79株。18例患者检出了中间普氏菌，总检出率为54．54％。共分离了32株。结论：厌氧培养，生化反应鉴定技术的发展，使牙龈卟啉菌和中间普氏菌的分离与培养准确可靠，为今后在分子水平上了解各菌株的致病机理打下了基础。     

Multiplex polymerase chain reaction assay for simultaneous detection of black-pigmented Prevotella species in oral specimens

Prevotella species are a major component of the oral microflora and some have been implicated in various forms of periodontal disease. Despite the importance of understanding the prevalence of these organisms in the oral microflora, no rapid, simultaneous detection system for these species has been reported. This study developed a multiplex polymerase chain reaction assay for the simultaneous detection of four oral black-pigmented Prevotella species in various oral specimens. This assay will be useful for determining the prevalence of these organisms in the oral ecosystem. Furthermore, this assay system should prove a useful tool for analyzing the role of black-pigmented Prevotella species in the mouth.     

Identical clonal types of Porphyromonas gingivalis or Prevotella nigrescens recovered from infected root canals and subgingival plaque

Clinical samples from 10 infected root canals and from subgingival plaque in 10 patients were screened by anaerobic culture for black-pigmented anaerobes. A total of 17 Porphyromonas gingivalis and 9 Prevotella nigrescens were obtained from four patients and were identified by species-specific polymerase chain reaction (PCR) amplification. The arbitrarily primed PCR reaction used to examine the genetic diversity of the isolates revealed that the P. gingivalis or P. nigrescens simultaneously present in the root canal system and in subgingival plaque of all four patients were genotypically indistinguishable. These data indicate that the endodontium and the periodontium can be colonized by the same clonal types of black-pigmented anaerobes.     

Quantitative detection of periodontal pathogens using real-time polymerase chain reaction with TaqMan probes

Quantitative analysis, with identification of periodontopathic bacteria, is important for the diagnosis, therapeutic evaluation and risk assessment of periodontal disease. We developed a highly sensitive and specific method using real-time polymerase chain reaction (PCR) to detect and quantify six periodontal bacteria: Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans, Treponema denticola, Prevotella intermedia, and Prevotella nigrescens. Species-specific TaqMan probe/primer sets were designed according to 16S ribosomal RNA gene sequences. Plaque and tongue debris specimens were collected from 10 patients with advanced periodontitis and 10 periodontal healthy individuals and analyzed. All species, except for P. nigrescens, were detected in samples from diseased sites in significantly greater numbers than in those from healthy sites, whereas greater numbers of P. nigrescens were found in the controls. These results suggest that the present real-time PCR method with the designed probe/primer sets enabled sensitive detection of the six periodontal bacteria, and may also assist future microbial studies of periodontal diseases.     

Antibody responses to suspected periodontal pathogens in elderly subjects with periodontal disease

Abstract Little is known about the relationship of aging to periodontal disease. The immune response undergoes aging-related changes resulting in loss of functional capacity. The aim of this study was to investigate the relationship between levels of serum IgG antibodies against suspected periodontal pathogenic microorganisms to the presence or absence of periodontal disease in an elderly (65-75 yrs) population. From this study, we obtained information concerning: (1) the ability to differentiate elderly individuals without disease from those with disease by their levels of antibodies against periodontal pathogens and (2) which periodontal pathogen(s) triggered those responses. IgG anti- Porphyromonas gingivalis (strains W83 and 381) levels in the serum of elderly patients with severe periodontal disease were the only antibody responses measured which were elevated compared to the elderly control group of subjects with no periodontal disease. Anti- Prevoiella intermedia IgG levels in both elderly patient groups were depressed compared to anti- P. intermedia levels in the young normal control subjects. Serum IgG antibody levels to six other plaque microorganisms did not differentiate between diseased and normal, elderly or young subjects. This data suggested that P. gingtvalis was associated with periodontal disease in this elderly group of individuals and that those elderly individuals were able to respond with a normal IgG immune response.     

Effect of non-surgical periodontal treatment on clinical parameters and the numbers of Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans at adult periodontitis sites

BACKGROUND, AIMS: The purpose of this study was to relate the numbers of Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans cells to clinical parameters at diseased and healthy periodontal sites before and after non-surgical periodontal therapy using a sensitive quantitative PCR method (Q-PCR). METHOD: The sensitivity of the Q-PCR was less than 10 cells for all three species. Subgingival plaque samples were collected from 541 sites in 50 adult periodontitis subjects pre-treatment, post-treatment and at a follow-up visit (3-6 months post-treatment). Pocket probing depth, attachment loss and bleeding on probing were recorded at each visit and both healthy and diseased sites in each subject were sampled. RESULTS: Quantification revealed that P. gingivalis counts were associated with pocket depth (p=0.006) and attachment loss (p=0.010); however, neither P. intermedia nor A. actinomycetemcomitans was associated with the clinical signs examined. Post-treatment, there was a significant decrease in the numbers of all three species in both the diseased and healthy sites (86-99%) but none were eradicated. Positive associations were found between any two of the three species studied both pre- and post-therapy. By the follow-up visit, there was a significant improvement in the probing depth of deep sites (p=0.001) but in no other clinical parameters. CONCLUSION: This study demonstrates the usefulness of Q-PCR for enumerating putative pathogens in clinical periodontal specimens and that the numbers of the three organisms in all sites decrease with non-surgical periodontal therapy.     

The natural history of periodontal disease

Abstract. The purpose of this study was to assess the prevalence of A. actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia , and their association with periodontal disease states in a population sample from Sri Lanka. Based on clinical parameters, a total of 536 sites in 268 male Sri Lankan tea workers were categorized as healthy, or showing gingivitis only, moderate or advanced periodontitis. Bacterial samples were obtained from all sites and the three target bacteria identified by indirect immunofluorescence. P. intermedia, P. gingivalis and A. actinomycetemcomitans were found in 76%, 40% and 15% of the subjects, respectively. Of the 536 periodontal sites. 10.5% were categorized with "no disease", 14%"gingivitis only"; 59% with moderate and 16% with advanced periodontitis. The prevalence of P. gingivalis and P. intermedia was significantly higher in sites with moderate and advanced periodontitis than in sites with no disease or gingivitis only. A. actinomycetemcomitans was not found in healthy sites, but occurred with equal frequency in sites with gingivitis, moderate and advanced periodontitis. The association between these three bacteria and periodontal diseases in Sri Lankan tea laborers was similar to that described for other non-industrialized and industrialized countries.     

Black-pigmenting gram-negative bacteria in periodontal disease. I. Topographic distribution in the human dentition

The purpose of this study was to determine the distribution of black-pigmenting Gram-negative bacteria in the dentition of periodontitis patients and to examine differences in the microbial composition of samples taken from a series of adjacent sites. Separate subgingival samples were taken from the mesial, buccal, distal and oral aspects of every tooth in 10 subjects. Thus, a total of 927 sites, 84 to 102 per patient, were scored clinically and sampled microbiologically. P. intermedia and P. melaninogenica were found in all subjects. P. gingivalis was found in 7. The organisms tended to be distributed unevenly, giving the impression of clusters of positive samples in certain areas of the dentition. 77% of all samples positive for P. gingivalis were also P. intermedia-positive. Premolars had lower frequencies and mean proportions of P. gingivalis than incisors and molars. In the premolar and molar region, frequencies and mean proportions of P. gingivalis increased with more posterior location. While frequencies indicated a similar topographic distribution of P. intermedia the mean proportions of this organism were more consistent at different locations. Based on a logistic regression model, it was estimated that the probability of detecting P. gingivalis was 34 times higher in any site which had at least 1 P. gingivalis-positive neighboring site. For P. intermedia any site with at least 1 P. intermedia-positive neighboring site had a chance 2.4 times higher of harboring the organism as well. The highest chance of detecting P. gingivalis and P. intermedia existed in deep, oral pockets of molars, which bled upon sampling.