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ObjectiveA history of periodontal disease and the presence of circulating antibodies to selected oral pathogens have been associated with increased risk of pancreatic cancer; however, direct relationships of oral microbes with pancreatic cancer have not been evaluated in prospective studies. We examine the relationship of oral microbiota with subsequent risk of pancreatic cancer in a large nested case–control study.DesignWe selected 361 incident adenocarcinoma of pancreas and 371 matched controls from two prospective cohort studies, the American Cancer Society Cancer Prevention Study II and the National Cancer Institute Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. From pre-diagnostic oral wash samples, we characterised the composition of the oral microbiota using bacterial 16S ribosomal RNA (16S rRNA) gene sequencing. The associations between oral microbiota and risk of pancreatic cancer, controlling for the random effect of cohorts and other covariates, were examined using traditional and L1-penalised least absolute shrinkage and selection operator logistic regression.ResultsCarriage of oral pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were associated with higher risk of pancreatic cancer (adjusted OR for presence vs absence=1.60 and 95% CI 1.15 to 2.22; OR=2.20 and 95% CI 1.16 to 4.18, respectively). Phylum Fusobacteria and its genus Leptotrichia were associated with decreased pancreatic cancer risk (OR per per cent increase of relative abundance=0.94 and 95% CI 0.89 to 0.99; OR=0.87 and 95% CI 0.79 to 0.95, respectively). Risks related to these phylotypes remained after exclusion of cases that developed within 2 years of sample collection, reducing the likelihood of reverse causation in this prospective study.ConclusionsThis study provides supportive evidence that oral microbiota may play a role in the aetiology of pancreatic cancer.

Periodontitis is a polymicrobial infection of tooth-supporting tissues. This cross-sectional study aimed to examine the associations between five target species and severe periodontitis in a Thai population. Using the CDC/AAP case definition, individuals diagnosed with no/mild and severe periodontitis were included. Quantitative analyses of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), and Prevotella intermedia (Pi) in subgingival plaque were performed using real-time polymerase chain reaction. The association between target species and severe periodontitis was examined using logistic regression analysis. The study subjects comprised 479 individuals with no/mild periodontitis and 883 with severe periodontitis. Bacterial prevalence and quantity were higher in subjects with severe periodontitis than in those with no/mild disease. In the fully adjusted model, all species except Tf showed a dose-dependent relationship with periodontitis. The mere presence of Pg, even in low amount, was significantly associated with severe periodontitis, while the amount of Aa, Td, and Pi had to reach the critical thresholds to be significantly associated with disease. Compared to individuals with low levels of both Td and Pi, high colonization by either Td or Pi alone significantly increased the odds of having severe periodontitis by 2.5 (95%CI 1.7-3.5) folds. The odds ratio was further increased to 14.8 (95%CI 9.2-23.8) in individuals who were highly colonized by both species. Moreover, the presence of Pg and high colonization by Aa were independently associated with severe periodontitis with odds ratios of 5.6 (95%CI 3.4-9.1) and 2.2 (95%CI 1.5-3.3), respectively. Our findings suggest that the presence of Pg and high colonization by Aa, Td, and Pi play an important role in severe periodontitis in this study population. We also demonstrate for the first time that individuals co-infected with Td and Pi were more likely to have periodontitis than were those infected with a single pathogen.

Aggregatibacter actinomycetemcomitans is a Gram-negative periodontitis-associated bacterium that expresses a toxin that selectively affects leukocytes. This leukotoxin is encoded by an operon belonging to the core genome of this bacterial species. Variations in the expression of the leukotoxin have been reported, and a well-characterized specific clonal type (JP2) of this bacterium with enhanced leukotoxin expression has been isolated. In particular, the presence of the JP2 genotype significantly increases the risk for the progression of periodontal attachment loss (AL). Based on these findings we hypothesized that variations in the leukotoxicity are linked to disease progression in infected individuals. In the present study, the leukotoxicity of 239 clinical isolates of A. actinomycetemcomitans was analysed with different bioassays, and the genetic peculiarities of the isolates were related to their leukotoxicity based on examination with molecular techniques. The periodontal status of the individuals sampled for the presence of A. actinomycetemcomitans was examined longitudinally, and the importance of the observed variations in leukotoxicity was evaluated in relation to disease progression. Our data show that high leukotoxicity correlates with an enhanced risk for the progression of AL. The JP2 genotype isolates were all highly leukotoxic, while the isolates with an intact leukotoxin promoter (non-JP2 genotypes) showed substantial variation in leukotoxicity. Genetic characterization of the non-JP2 genotype isolates indicated the presence of highly leukotoxic genotypes of serotype b with similarities to the JP2 genotype. Based on these results, we conclude that A. actinomycetemcomitans harbours other highly virulent genotypes besides the previously described JP2 genotype. In addition, the results from the present study further highlight the importance of the leukotoxin as a key virulence factor in aggressive forms of periodontitis.

Periodontitis is a loss of supporting connective tissue and alveolar bone around teeth, and if it occurs in an aggressive form it can lead to tooth loss before the age of 20 years. Although the cause of periodontitis in general remains elusive, a particular clone (JP2) of the gram-negative rod Aggregatibacter (Actinobacillus) actinomycetemcomitans is considered a possible aetiological agent of the aggressive form in adolescents living in or originating from north and west Africa, where the disease is highly prevalent. We did a population-based longitudinal study of adolescents to assess the role of the JP2 clone in the initiation of aggressive periodontitis. A total of 700 adolescents from public schools in Rabat, Morocco, were enrolled in the study. We used PCR to detect A actinomycetemcomitans in plaque samples (taken from molar and incisor sites) and to differentiate between the JP2 clone and other non-JP2 genotypes of the bacterium. 18 individuals were found to already have periodontitis and were excluded. The 682 periodontally healthy adolescents (mean age 12·5 years; SD 1·0) were classified according to their A actinomycetemcomitans carrier status at baseline. After 2 years, 428 (62·8%) individuals returned for re-examination, which included recording of periodontal attachment loss measured from the cemento-enamel junction to the bottom of the periodontal pockets of all teeth present. Individuals who carried the JP2 clone of A actinomycetemcomitans alone (relative risk 18·0; 95% CI 7·8–41·2, p<0·0001) or together with non-JP2 clones of A actinomycetemcomitans (12·4; 5·2–29·9, p<0·0001) had a significantly increased risk of periodontal attachment loss. A much less pronounced disease risk was found in those carrying non-JP2 clones only (3·0; 1·3–7·1, p=0·012). The JP2 clone of A actinomycetemcomitans is likely to be an important aetiological agent in initiation of periodontal attachment loss in children and adolescents. Co-occurrence of non-JP2 clones of A actinomycetemcomitans reduces the risk of development of periodontitis, suggesting competition for the ecological niche between the JP2 and non-JP2 clones of this species.

Photoactivated disinfection has a strong local antimicrobial effect. In the field of dentistry it is an emerging adjunct to mechanical debridement during endodontic and periodontal treatment. In the present study, we investigate the effect of photoactivated disinfection using riboflavin as a photosensitizer and blue LED light for activation, and compare it to photoactivated disinfection with the widely used combination of toluidine blue O and red light. Riboflavin is highly biocompatible and can be activated with LED lamps at hand in the dental office. To date, no reports are available on the antimicrobial effect of photoactivated disinfection using riboflavin/blue light on oral microorganisms. Planktonic cultures of eight organisms frequently isolated from periodontal and/or endodontic lesions (Aggregatibacter actinomycetemcomitans, Candida albicans, Enterococcus faecalis, Escherischia coli, Lactobacillus paracasei, Porphyromonas gingivalis, Prevotella intermedia and Propionibacterium acnes) were subjected to photoactivated disinfection with riboflavin/blue light and toluidine blue O/red light, and survival rates were determined by CFU counts. Within the limited irradiation time of one minute, photoactivated disinfection with riboflavin/blue light only resulted in minor reductions in CFU counts, whereas full kills were achieved for all organisms when using toluidine blue O/red light. The black pigmented anaerobes P. gingivalis and P. intermedia were eradicated completely by riboflavin/blue light, but also by blue light treatment alone, suggesting that endogenous chromophores acted as photosensitizers in these bacteria. On the basis of our results, riboflavin cannot be recommended as a photosensitizer used for photoactivated disinfection of periodontal or endodontic infections.

Aggregatibacter actinomycetemcomitans (Aa), a Gram-negative coccobacillus commonly associated with endocarditis, poses a rare diagnostic challenge in pediatric cases. The presentation of two pediatric cases—myositis and chest mass—highlights novel aspects, including unusual symptom presentations in children which can be mistaken for malignancy. The limited sensitivity of standard blood tests complicates diagnosis, leading to delayed diagnosis and treatment. Representative samples must be taken, especially if blood cultures are negative. Despite advances in detection methods, diagnosing Aa infection remains difficult due to its rarity in children and variable clinical presentation. In conclusion, a comprehensive understanding of Aa infection in children is essential for early and effective diagnostic and therapeutic management.

Aim: The aim of the current investigation was to detect serotypes of Aggregatibacter actinomycetemcomitans in a cohort of Western Australians diagnosed with periodontitis. Materials and Methods: A total of 64 subjects were selected. Intra-oral samples were taken from every subject in the present investigation. Periodontal, radiographical, and microbiological analyses were conducted. A polymerase chain reaction was employed to investigate the presence of Aggregatibacter actinomycetemcomitans serotypes. Results: Only twelve (18.75%) patients were tested positive for Aggregatibacter actinomycetemcomitans. The most dominant serotypes of Aggregatibacter actinomycetemcomitans in this group were serotype e (80.55%), followed by serotype c (52.77%). Both serotypes b and d were absent in the present investigation. Serotype e presented in isolation or combined with other serotypes. The other serotypes tend to be present alone, but when they were isolated together, they were always combined with serotype e. It seems that serotype e of Aggregatibacter actinomycetemcomitans is associated with those who live in rural areas (p = 0.003), and those with low education (p = 0.041), and severe forms of periodontitis in this cohort. Conclusions: In patients diagnosed with severe periodontitis, serotype e was dominant in this population. Serotypes b and d did not appear in the present study.

Purpose This study aimed to quantify Aggregatibacter actinomycetemcomitans ( A.a ) and Porphyromonas gingivalis ( P.g ) from the mouth of head and neck irradiated and cancer-free patients. Methods Information such as age, presence of tongue coating, salivary flow, and biofilm were collected from head and neck irradiated patients (Group 1) and compared the results with a group of cancer-free individuals (Group 2). The presence of tongue coating was clinically examined. Sialometry was performed through a stimulating technique by chewing paraffin. Microbiological samples were collected from buccal and labial mucosa and tongue dorsum. Subsequently, the samples were processed and analyzed by qPCR to detect the presence and quantify the bacteria. Results There was a statistical difference in the quantity of bacteria among the 24 individuals in Group 1 ( A.a , 2817 ± 8718; P.g , 3145 ± 11297) and 26 individuals in Group 2 ( A.a , 133996 ± 398545; P.g , 60 ± 195) regarding tongue coating (Group 1, A.a 2194.6 ± 4641.5; Group 2, A.a 92767.8 ± 333385.7) and salivary volume (Group 1, 0.69 mL; Group 2, 3.09 mL). The linear regression analysis found that the variable group was the main responsible for the difference in the quantity of periodontal pathogens ( p -value < 0.001). There was no statistical difference in the amount of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis between totally edentulous and partially edentulous (with 12 or fewer teeth) patients. Conclusion Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were present in significant amounts in patients of both groups, with a greater quantity in cancer-free individuals.

The most common type of periodontal disease is chronic periodontitis, an inflammatory condition caused by pathogenic bacteria in subgingival plaque. The aim of our study was the development of a real-time PCR test as a diagnostic tool for the detection and differentiation of five periodontopathogenic bacteria, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Treponema denticola, in patients with periodontitis. We compared the results of our in-house method with the micro-IDent® semiquantitative commercially available test based on the PCR hybridization method. DNA was isolated from subgingival plaque samples taken from 50 patients and then analyzed by both methods. Comparing the results of the two methods, they show a specificity of 100% for all bacteria. The sensitivity for A. actinomycetemcomitans was 97.5%, for P. gingivalis 96.88%, and for P. intermedia 95.24%. The sensitivity for Tannerella forsythia and T. denticola was 100%. The Spearman correlation factor of two different measurements was 0.976 for A. actinomycetemcomitans, 0.967 for P. gingivalis, 0.949 for P. intermedia, 0.966 for Tannerella forsythia, and 0.917 for T. denticola. In conclusion, the in-house real-time PCR method developed in our laboratory can provide information about relative amount of five bacterial species present in subgingival plaque in patients with periodontitis. It is likely that such a test could be used in dental diagnostics in assessing the efficacy of any treatment to reduce the bacterial burden.

The Gram-positive organism Filifactor alocis is implicated in multiple oral diseases including periodontitis, and approximately 50% of known strains encode and produce a recently identified repeat-in-toxin (RTX) protein, FtxA, partly homologous to the Aggregatibacter actinomycetemcomitans leukotoxin. By assessing a longitudinal Ghanaian study population of adolescents, we recently identified a possible correlation between F. alocis levels, ftxA gene carriage, and progression of clinical attachment loss (CAL). To extend knowledge on the possible significance of F. alocis and its FtxA in periodontal disease, we have in the present work analyzed saliva samples in an independent cohort of periodontitis (n=156), collected at two private periodontal specialist practices in Perth, Western Australia. The present results corroborate that high loads of F. alocis and the presence of its ftxA gene together are associated with parameters of periodontal tissue destruction and severity. Moreover, among the individuals carrying A. actinomycetemcomitans , a majority also exhibited an ftxA -positive F. alocis , supporting the notion of the synergistic behavior of these two species. This emphasizes that F. alocis and its ftxA are involved in the pathogenesis of periodontitis and may have ecological roles, with diagnostic and prognostic implications for the disease.