Articoli di riviste: "Porphyromonas gingivalis infections"

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Winkelhoff, Arie J., e Jørgen Slots. "Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in nonoral infections". Periodontology 2000 20, n. 1 (giugno 1999): 122–35. http://dx.doi.org/10.1111/j.1600-0757.1999.tb00160.x.

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Condorelli, Francesca, Guido Scalia, Giuditta Calì, Bruno Rossetti, Giuseppe Nicoletti e Anna M. Lo Bue. "Isolation of Porphyromonas gingivalisand Detection of Immunoglobulin A Specific to Fimbrial Antigen in Gingival Crevicular Fluid". Journal of Clinical Microbiology 36, n. 8 (1998): 2322–25. http://dx.doi.org/10.1128/jcm.36.8.2322-2325.1998.

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The present study evaluated the prevalence of Porphyromonas gingivalis and the correlation between the bacterial culture method and the detection of immunoglobulin A (IgA) specific to theP. gingivalis fimbrial antigen in gingival crevicular fluid (GCF). P. gingivalis was isolated from 78.3% of subgingival plaque samples obtained from active sites and 34.7% of those from inactive sites of periodontal patients. P. gingivalis was isolated from only 4.7% of healthy subjects (control group). Immunoglobulins specific to the P. gingivalis fimbrial antigen were detected by enzyme-linked immunosorbent assay (ELISA). The overall agreement between the results of the P. gingivalis culture method and the results of specific IgA detection in periodontal patients was 71.7% for active sites and 58.7% for inactive sites. IgA specific to P. gingivalis was absent in GCF from all of the sites of healthy subjects. The results suggest that P. gingivalis is associated with the local production of specific IgA. The detection of IgA antibodies specific to P. gingivalis in GCF by ELISA may be used as a predictive parameter to reveal the early phase of the activation of recurrent periodontal infections.

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Hirasawa, Masaaki, e Tomoko Kurita-Ochiai. "Porphyromonas gingivalis Induces Apoptosis and Autophagy via ER Stress in Human Umbilical Vein Endothelial Cells". Mediators of Inflammation 2018 (29 luglio 2018): 1–8. http://dx.doi.org/10.1155/2018/1967506.

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It has been reported that periodontitis is associated with an increased risk of atherosclerosis. Accumulating evidence suggests that endothelial dysfunction is an early marker for atherosclerosis. To determine how periodontal infections contribute to endothelial dysfunction, we examined the effect of Porphyromonas gingivalis on human umbilical vein endothelial cells (HUVEC). P. gingivalis significantly suppressed the viability of HUVEC, induced DNA fragmentation and annexin V staining, and increased caspase-3, caspase-8, and caspase-9 activities. P. gingivalis also increased the expression of GADD153 and GRP78 and caspase-12 activity. Further, P. gingivalis induced autophagy, as evidenced by increased LC3-II and Beclin-1 levels. The suppression of P. gingivalis-induced autophagy by silencing of LC3 with siRNA significantly increased P. gingivalis-induced apoptosis. ER stress inhibitor, salubrinal, suppressed apoptosis and autophagy by inhibiting P. gingivalis-induced DNA fragmentation and LC3-II expression. These data suggest that P. gingivalis infection induces ER stress-mediated apoptosis followed by autophagic response that protects HUVEC from P. gingivalis-mediated apoptosis, potentially amplifying proatherogenic mechanisms in the perturbed vasculature.

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Wu, Jie, e Hua Xie. "Role of Arginine Deiminase of Streptococcus cristatus in Porphyromonas gingivalis Colonization". Antimicrobial Agents and Chemotherapy 54, n. 11 (26 luglio 2010): 4694–98. http://dx.doi.org/10.1128/aac.00284-10.

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ABSTRACT The ability to attach to a variety of oral surfaces is an important characteristic of Porphyromonas gingivalis. Previous studies have demonstrated that expression and production of FimA, a major subunit protein of the long fimbriae, is required for P. gingivalis colonization. Here we report that a surface protein, arginine deiminase (ArcA) of Streptococcus cristatus, represses FimA production and inhibits biofilm formation of P. gingivalis. This inhibitory function of ArcA is also observed in the formation of heterotypic P. gingivalis-Streptococcus gordonii biofilms. P. gingivalis is released from streptococcal substrates in the presence of ArcA, likely due to an inhibition of FimA production. This work suggests that ArcA may have the potential to be a specific antibiofilm agent to fight P. gingivalis infections.

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Rôças, Isabela N., e José F. Siqueira. "Distribution of Porphyromonas gingivalis fimA genotypes in primary endodontic infections". Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 109, n. 3 (marzo 2010): 474–78. http://dx.doi.org/10.1016/j.tripleo.2009.11.009.

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Odell, Lynnetta J., J. Craig Baumgartner, Tian Xia e Larry L. David. "Survey for collagenase gene prtC in Porphyromonas gingivalis and Porphyromonas endodontalis isolated from endodontic infections". Journal of Endodontics 25, n. 8 (agosto 1999): 555–58. http://dx.doi.org/10.1016/s0099-2399(99)80379-3.

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Fiorillo, Luca, Gabriele Cervino, Luigi Laino, Cesare D’Amico, Rodolfo Mauceri, Tolga Fikret Tozum, Michele Gaeta e Marco Cicciù. "Porphyromonas gingivalis, Periodontal and Systemic Implications: A Systematic Review". Dentistry Journal 7, n. 4 (11 dicembre 2019): 114. http://dx.doi.org/10.3390/dj7040114.

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In recent scientific literature, oral infections and systemic manifestations, or correlations between oral health and systemic diseases are a topic of discussion. Porphyromonas gingivalis is one of the bacteria implicated in the biofilm formation of bacterial plaque, and plays an important role in the progression of periodontal disease. In this systematic review authors have evaluated the literature of the last 10 years on P. gingivalis and all the systemic implications proven. This study therefore evaluates all the districts of the organism in which this bacterium may have implications. From the results it emerges that P. gingivalis has implications in the onset of different systemic pathologies, including rheumatoid arthritis, cardiovascular pathologies, and neurodegenerative pathologies. Surely, understanding the mechanisms of diffusion of this bacterium, it would be possible to prevent a series of pathologies. Thus, putting the dentist clinician at the center of prevention for these diseases.

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Maezono, H., Y. Noiri, Y. Asahi, M. Yamaguchi, R. Yamamoto, N. Izutani, H. Azakami e S. Ebisu. "Antibiofilm Effects of Azithromycin and Erythromycin on Porphyromonas gingivalis". Antimicrobial Agents and Chemotherapy 55, n. 12 (12 settembre 2011): 5887–92. http://dx.doi.org/10.1128/aac.05169-11.

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ABSTRACTAntibiotic resistance of biofilm-grown bacteria contributes to chronic infections, such as marginal and periapical periodontitis, which are strongly associated withPorphyromonas gingivalis. Concurrent azithromycin (AZM) administration and mechanical debridement improve the clinical parameters of periodontal tissuein situ. We examined thein vitroefficacy of AZM againstP. gingivalisbiofilms. The susceptibilities of adherentP. gingivalisstrains 381, HW24D1, 6/26, and W83 to AZM, erythromycin (ERY), ampicillin (AMP), ofloxacin (OFX), and gentamicin (GEN) were investigated using a static model. The optical densities of adherentP. gingivaliscells were significantly decreased by using AZM and ERY at sub-MIC levels compared with those of the controls in all the strains tested, except for the effect of ERY on strain W83. AMP and OFX inhibitedP. gingivalisadherent cells at levels over their MICs, and GEN showed no inhibition in the static model. The effects of AZM and ERY against biofilm cells were investigated using a flow cell model. The ATP levels ofP. gingivalisbiofilms were significantly decreased by AZM at concentrations below the sub-MICs; however, ERY was not effective for inhibition ofP. gingivalisbiofilm cells at their sub-MICs. Furthermore, decreased density ofP. gingivalisbiofilms was observed three-dimensionally with sub-MIC AZM, using confocal laser scanning microscopy. These findings suggest that AZM is effective againstP. gingivalisbiofilms at sub-MIC levels and could have future clinical application for oral biofilm infections, such as chronic marginal and periapical periodontitis.

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Siqueira, José F., Isabela N. Rôças e Marlei G. Silva. "Prevalence and Clonal Analysis of Porphyromonas gingivalis in Primary Endodontic Infections". Journal of Endodontics 34, n. 11 (novembre 2008): 1332–36. http://dx.doi.org/10.1016/j.joen.2008.08.021.

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Loos, B. G., D. Mayrand, R. J. Genco e D. P. Dickinson. "Genetic Heterogeneity of Porphyromonas (Bacteroides) gingivalis by Genomic DNA Fingerprinting". Journal of Dental Research 69, n. 8 (agosto 1990): 1488–93. http://dx.doi.org/10.1177/00220345900690080801.

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This study describes the use of total genomic DNA fingerprinting with the use of restriction endonucleases to characterize clinical isolates of Porphyromonas gingivalis (Bacteroides gingivalis) obtained from patients with periodontitis or with root-canal infections. The majority of independent isolates had a unique DNA fingerprint, indicating extensive genetic heterogeneity within this species. Twenty-nine distinct DNA fingerprints were found among the 33 isolates investigated. This is in contrast to biotyping and serotyping, where only one type and three types, respectively, have been reported. The observed heterogeneity indicates that DNA fingerprinting is a sensitive measure of genetic dissimilarity between P. gingivalis isolates and is able to characterize individual isolates. These results have ecological implications, indicating that there is considerable natural diversity in the global population of P. gingivalis, and that there are likely to be relatively large numbers of genetically distinct clonal lines. Furthermore, DNA fingerprinting is a sensitive and powerful tool for longitudinal and cross-sectional epidemiological studies. This technique provides far greater discrimination between isolates than either biotyping or serotyping, and will be most helpful in, for example, the analysis of distribution of clonal lines within one periodontal patient, or the analysis of the transmission to and turnover of strain populations within a patient population, since the probability of two strains with the same DNA fingerprint being found by chance is small.

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Pyrc, Krzysztof, Paulina Strzyz, Aleksandra Milewska, Anna Golda, Oliver Schildgen e Jan Potempa. "Porphyromonas gingivalis enzymes enhance infection with human metapneumovirus in vitro". Journal of General Virology 92, n. 10 (1 ottobre 2011): 2324–32. http://dx.doi.org/10.1099/vir.0.032094-0.

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Relatively recently discovered, human metapneumovirus (HMPV) is a human pathogen with worldwide prevalence, accounting for a substantial percentage of respiratory tract diseases. Concurrent viral and bacterial infections enable intricate mechanisms of cooperation between pathogens, which complicate the symptoms and outcome of the disease. Such bilateral interactions are based on the modulation of bacterial growth on epithelium pathologically altered during viral illness and the modulation of immune responses, as well as the enhancement of virus replication by bacterial virulence factors. This study showed that proteases produced by Porphyromonas gingivalis, a Gram-negative bacterium implicated in the development of periodontitis, named gingipains, facilitated HMPV replication in LLC-MK2 cells and may contribute to HMPV pathogenicity in patients with periodontitis. Gingipains at low nanomolar concentrations enabled HMPV replication and allowed virus propagation in vitro. In contrast to previously published data for influenza virus, however, Staphylococcus aureus proteases and human neutrophil elastase did not affect virus replication.

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Cao, H., Z. Qi, H. Jiang, J. Zhao, Z. Liu e Z. Tang. "Detection of Porphyromonas endodontalis, Porphyromonas gingivalis and Prevotella intermedia in primary endodontic infections in a Chinese population". International Endodontic Journal 45, n. 8 (19 marzo 2012): 773–81. http://dx.doi.org/10.1111/j.1365-2591.2012.02035.x.

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Jacinto, R. C., B. P. F. A. Gomes, H. N. Shah, C. C. Ferraz, A. A. Zaia e F. J. Souza-Filho. "Incidence and antimicrobial susceptibility of Porphyromonas gingivalis isolated from mixed endodontic infections". International Endodontic Journal 39, n. 1 (3 gennaio 2006): 62–70. http://dx.doi.org/10.1111/j.1365-2591.2005.01053.x.

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Kesavalu, Lakshmyya, Sabapathi Sathishkumar, Vasudevan Bakthavatchalu, Chad Matthews, Dolph Dawson, Michelle Steffen e Jeffrey L. Ebersole. "Rat Model of Polymicrobial Infection, Immunity, and Alveolar Bone Resorption in Periodontal Disease". Infection and Immunity 75, n. 4 (8 gennaio 2007): 1704–12. http://dx.doi.org/10.1128/iai.00733-06.

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ABSTRACT One of the predominant polymicrobial infections of humans is expressed clinically as periodontal disease. Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia have been strongly implicated as members of a pathogenic consortium in the etiology of adult periodontitis. In this study we hypothesized that P. gingivalis, T. denticola, and T. forsythia are synergistic in terms of virulence potential and induce chronic periodontal inflammation that leads to alveolar bone resorption in a polymicrobial infection in rats. Groups of rats were infected with either P. gingivalis, T. denticola, or T. forsythia in monomicrobial infections or with all three species in polymicrobial oral infections with or without Fusobacterium nucleatum. PCR analyses of oral microbial samples demonstrated that rats infected with one bacterium were orally colonized by each of the bacteria during the study interval, and increased serum immunoglobulin G (IgG) antibody levels substantiated the interaction of the host with the infecting bacteria. PCR analyses of the rats with polymicrobial infections demonstrated that most rats were infected with P. gingivalis, T. denticola, and T. forsythia as a consortium. Furthermore, all rats exhibited a significant increase in the level of IgG antibody to the polymicrobial consortium. Radiographic measurement of alveolar bone resorption showed that rats infected with the polymicrobial consortium with or without F. nucleatum exhibited significantly increased alveolar bone resorption compared to the resorption in uninfected control rats, as well as the resorption in rats infected with one of the microbes. These results documented that P. gingivalis, T. denticola, and T. forsythia not only exist as a consortium that is associated with chronic periodontitis but also exhibit synergistic virulence resulting in the immunoinflammatory bone resorption characteristic of periodontitis.

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Zhang, Ping, Jianzhong Liu, Qingan Xu, Gregory Harber, Xu Feng, Suzanne M. Michalek e Jenny Katz. "TLR2-dependent Modulation of Osteoclastogenesis by Porphyromonas gingivalis through Differential Induction of NFATc1 and NF-κB". Journal of Biological Chemistry 286, n. 27 (12 maggio 2011): 24159–69. http://dx.doi.org/10.1074/jbc.m110.198085.

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Osteolytic diseases, including rheumatoid arthritis, osteomyelitis, and periodontitis, are usually associated with bacterial infections. However, the precise mechanisms by which bacteria induce bone loss still remain unclear. Evidence exists that Toll-like receptor (TLR) signaling regulates both inflammation and bone metabolism and that the receptor activator of NF-κB ligand (RANKL) and its receptor RANK are the key regulators for bone remodeling and for the activation of osteoclasts. Here, we investigate the direct effects of the periodontal pathogen Porphyromonas gingivalis on osteoclast differentiation and show that P. gingivalis differentially modulates RANKL-induced osteoclast formation contingent on the state of differentiation of osteoclast precursors. In addition, although an optimal induction of cytokines by P. gingivalis is dependent on TLR2 and TLR4, as well as myeloid differentiation factor 88 and Toll/IL-1R domain-containing adaptor-inducing IFN-β, P. gingivalis utilizes TLR2/ myeloid differentiation factor 88 in modulating osteoclast differentiation. P. gingivalis modulates RANKL-induced osteoclast formation by differential induction of NFATc1 and c-Fos. More importantly, RANKL-mediated lineage commitment also has an impact on P. gingivalis-induced cytokine production. RANKL inhibits P. gingivalis-induced cytokine production by down-regulation of TLR/NF-κB and up-regulation of NFATc1. Our findings reveal novel aspects of the interactions between TLR and RANK signaling and provide a new model for understanding the mechanism underlying the pathogenesis of bacteria-mediated bone loss.

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Teng, Y. T. A. "Protective and Destructive Immunity in the Periodontium: Part 1—Innate and Humoral Immunity and the Periodontium". Journal of Dental Research 85, n. 3 (marzo 2006): 198–208. http://dx.doi.org/10.1177/154405910608500301.

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Based on the results of recent research in the field, the present paper will discuss the protective and destructive aspects of the innate vs. adaptive (humoral and cell-mediated) immunity associated with the bacterial virulent factors or antigenic determinants during periodontal pathogenesis. Attention will be focused on: (i) the Toll-like receptors (TLR), the innate immune repertoire for recognizing the unique molecular patterns of microbial components that trigger innate and adaptive immunity for effective host defenses, in some general non-oral vs. periodontal microbial infections; (ii) T-cell-mediated immunity, Th-cytokines, and osteoclastogenesis in periodontal disease progression; and (iii) some molecular techniques developed and used to identify critical microbial virulence factors or antigens associated with host immunity (using Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis as the model species). Therefore, further understanding of the molecular interactions and mechanisms associated with the host’s innate and adaptive immune responses will facilitate the development of new and innovative therapeutics for future periodontal treatments. Abbreviations used in the paper are as follows: A. actinomycetemcomitans ( Aa), Actinobacillus actinomycetemcomitans; Ab, antibody; DC, dendritic cells; mAb, monoclonal antibody; pAb, polyclonal antibody; PAMP, pathogen-associated molecular patterns; P. gingivalis ( Pg), Porphyromonas gingivalis; and TLR, Toll-like receptors.

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Allaker, R. P., K. A. Young, T. Langlois, R. de Rosayro e J. M. Hardie. "Dental Plaque Flora of the Dog with Reference to Fastidious and Anaerobic Bacteria Associated with Bites". Journal of Veterinary Dentistry 14, n. 4 (dicembre 1997): 127–30. http://dx.doi.org/10.1177/089875649701400401.

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Animal bite wounds are amongst the most common types of traumatic injuries in humans. The organisms isolated from these wounds generally reflect the oral flora of the biting animal and may be fastidious in nature and difficult to identify. This study was undertaken to determine the prevalence of Eikenella corrodens, Actinobacillus actinomycetemcomitans, Porphyromonas and Prevotella spp. in supragingival dental plaque collected from the right maxillary canine and carnassial teeth and the right mandibular canine tooth of dogs. In part one of the study, 30 dogs were used. E. corrodens was found in 62% of these dogs and 44% of individual plaque samples. A. actinomycetemcomitans was not detected in any of the dogs sampled. In pan two, 34 dogs were used to determine the prevalence of the black pigmented anaerobic bacilli (Porphyromonas and Prevotella spp.). Porphyromonas gingivalis was present in 68% of these dogs and 47% of individual plaque samples. Prevotella intermedia was present in 44% of the dogs and 23% of individual plaque samples. The recently described Porphyromonas canoris, Porphyromonas salivosa, Porphyromonas cangingivalis, Porphyromonas cansulci, Porphyromonas crevioricanis and Prevotella denticola species were isolated from only 9%, 6%, 3%, 3%, 3% and 3% of dogs respectively. Porphyromonas gingivicanis was not isolated from any of the animals sampled. In conclusion, black-pigmented anaerobic bacilli were isolated from 91% of the animals sampled and therefore constitute a significant risk with respect to bite wound infections. It is also suggested that the prevalence of E. corrodens in wound infections has been underestimated in previous reports because of use of inappropriate techniques for detecting this organism.

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Lopatin, Dennis E., Allison Combs, Domenica G. Sweier, J. Christopher Fenno e Sangeeta Dhamija. "Characterization of Heat-Inducible Expression and Cloning of HtpG (Hsp90 Homologue) of Porphyromonas gingivalis". Infection and Immunity 68, n. 4 (1 aprile 2000): 1980–87. http://dx.doi.org/10.1128/iai.68.4.1980-1987.2000.

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ABSTRACT Porphyromonas gingivalis is implicated in the etiology of periodontal disease. Associations between microbial virulence and stress protein expression have been identified in other infections. For example, Hsp90 homologues in several microbial species have been shown to contribute to virulence. We previously reported that P. gingivalis possessed an Hsp90 homologue (HtpG) which cross-reacts with human Hsp90. In addition, we found that elevated levels of serum antibody to Hsp90 stress protein in individuals colonized with this microorganism were associated with periodontal health. However, the role of HtpG in P. gingivalis has not been explored. Therefore, we cloned the htpG gene and investigated the characteristics of HtpG localization and expression in P. gingivalis. htpG exists as a single gene of 2,052 bp from which a single message encoding a mature protein of approximately 68 kDa is transcribed. Western blot analysis revealed that the 68-kDa polypeptide was stress inducible and that a major band at 44 kDa and a minor band at 40 kDa were present at constitutive levels. Cellular localization studies revealed that the 44- and 40-kDa species were associated with membrane and vesicle fractions, while the 68-kDa polypeptide was localized to the cytosolic fractions.

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Núñez-Acurio, Daniela, Denisse Bravo e Francisco Aguayo. "Epstein–Barr Virus—Oral Bacterial Link in the Development of Oral Squamous Cell Carcinoma". Pathogens 9, n. 12 (18 dicembre 2020): 1059. http://dx.doi.org/10.3390/pathogens9121059.

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Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer. Its development has been associated with diverse factors such as tobacco smoking and alcohol consumption. In addition, it has been suggested that microorganisms are risk factors for oral carcinogenesis. Epstein–Barr virus (EBV), which establishes lifelong persistent infections and is intermittently shed in the saliva, has been associated with several lymphomas and carcinomas that arise in the oral cavity. In particular, it has been detected in a subset of OSCCs. Moreover, its presence in patients with periodontitis has also been described. Porphyromonas gingivalis (P. gingivalis) is an oral bacterium in the development of periodontal diseases. As a keystone pathogen of periodontitis, P. gingivalis is known not only to damage local periodontal tissues but also to evade the host immune system and eventually affect systemic health. Persistent exposure to P. gingivalis promotes tumorigenic properties of oral epithelial cells, suggesting that chronic P. gingivalis infection is a potential risk factor for OSCC. Given that the oral cavity serves as the main site where EBV and P. gingivalis are harbored, and because of their oncogenic potential, we review here the current information about the participation of these microorganisms in oral carcinogenesis, describe the mechanisms by which EBV and P. gingivalis independently or synergistically can collaborate, and propose a model of interaction between both microorganisms.

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Inagaki, Satoru, Shinsuke Onishi, Howard K. Kuramitsu e Ashu Sharma. "Porphyromonas gingivalis Vesicles Enhance Attachment, and the Leucine-Rich Repeat BspA Protein Is Required for Invasion of Epithelial Cells by “Tannerella forsythia”". Infection and Immunity 74, n. 9 (settembre 2006): 5023–28. http://dx.doi.org/10.1128/iai.00062-06.

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ABSTRACTThe human oral cavity harbors more than 500 species of bacteria. Periodontitis, a bacterially induced inflammatory disease that leads to tooth loss, is believed to result from infection by a select group of gram-negative periodontopathogens that includesPorphyromonas gingivalis,Treponema denticola, and “Tannerella forsythia” (opinion on name change fromTannerella forsythensispending; formerlyBacteroides forsythus). Epithelial cell invasion by periodontopathogens is considered to be an important virulence mechanism for evasion of the host defense responses. Further, the epithelial cells with invading bacteria also serve as reservoirs important in recurrent infections. The present study was therefore undertaken to address the epithelial cell adherence and invasion properties ofT. forsythiaand the role of the cell surface-associated protein BspA in these processes. Further, we were interested in determining ifP. gingivalis, one of the pathogens frequently found associated in disease, or its outer membrane vesicles (OMVs) could modulate the epithelial cell adherence and invasion abilities ofT. forsythia. Here we show that epithelial cell attachment and invasion byT. forsythiaare dependent on the BspA protein. In addition,P. gingivalisor its OMVs enhance the attachment and invasion ofT. forsythiato epithelial cells. Thus, interactions between these two bacteria may play important roles in virulence by promoting host cell attachment and invasion.

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Socransky, Sigmund S., Anne D. Haffajee, Laurie Ann Ximenez-Fyvie, Magda Feres e Donna Mager. "Ecological considerations in the treatment of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis periodontal infections". Periodontology 2000 20, n. 1 (giugno 1999): 341–62. http://dx.doi.org/10.1111/j.1600-0757.1999.tb00165.x.

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Wikström, M., J. L. Wennstrom, S. Renvert e R. Jonsson. "Immunohistological characteristics of periodontal lesions associated with Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans infections". Oral Microbiology and Immunology 11, n. 1 (febbraio 1996): 1–7. http://dx.doi.org/10.1111/j.1399-302x.1996.tb00329.x.

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Alshammari, Hatem, Jessica Neilands, Gunnel Svensäter e Andreas Stavropoulos. "Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis". Antibiotics 10, n. 2 (3 febbraio 2021): 150. http://dx.doi.org/10.3390/antibiotics10020150.

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Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)2 against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)2 (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)2 tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)2 showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)2 has antimicrobial properties against bacteria associated with peri-implantitis.

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Kalburgi, Nagaraj B., Arati C. Koregol, Ruchita S. Patil e Tejashwini Puttarevanna. "ANTI-MICROBIAL EFFICACY OF AN ETHANOLIC EXTRACT OF MURRAYA KOENIGII AGAINST PERIODONTAL PATHOGENS LIKE PORPHYROMONAS GINGIVALIS AND AGGREGATIBACTER ACTINOMYCETEMCOMITANS: IN VITRO ANALYSIS". International Journal of Research in Ayurveda and Pharmacy 12, n. 3 (6 luglio 2021): 41–45. http://dx.doi.org/10.7897/2277-4343.120371.

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Periodontitis is primarily an infectious disease with Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans present in plaque biofilm as the key pathogens, causing destruction of supporting periodontal tissues. Herbal formulations are widely substituting synthetic anti-microbials due to their minimal adverse effects and cost effectiveness. Murraya koenigii (M. koenigii) is a well-known anti-microbial agent used in treating systemic infections. Hence its anti-microbial efficacy against key periodontal pathogens also needs to be tested. The aim of this study is to determine Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and zone of inhibition of M. koenigii ethanolic extract against P. gingivalis and A. actinomycetemcomitans. Thioglycollate agar was used for culturing both P. gingivalis and A. actinomycetemcomitans. For determination of MIC and MBC broth dilution technique was used. For MIC, serial dilutions of extract were made and culture tubes were incubated in an anaerobic jar and observed for their turbidity. For MBC determination, dilution tubes sensitive to MIC were plated and incubated for the next 24 hours to monitor growth, and colony count was taken. MIC results showed A. actinomycetemcomitans was more sensitive to M. koenigii extract than P. gingivalis and got inhibited at 0.8 μg/ml. Also, MBC results showed extract has strong bactericidal activity towards A. actinomycetemcomitans. Disk diffusion test results showed bactericidal activity against both A. actinomycetemcomitans and P. gingivalis with a larger inhibition zone (15 mm) towards P. gingivalis at a concentration of 75 μl/ml. M. koenigii ethanolic extract is bactericidal against periodontal pathogens like A. actinomycetemcomitans and P. gingivalis and can be used as a safe and effective alternative for synthetic chemotherapeutic agents in the future.

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Zhu, Hongguang, Shouyi Lu, Meirong Wei, Xiaoshan Cai e Guoyou Wang. "Identification of novel genes involved in gingival epithelial cells responding to Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis infections". Archives of Oral Biology 96 (dicembre 2018): 113–21. http://dx.doi.org/10.1016/j.archoralbio.2018.08.017.

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26

Curtis, M. A., J. Aduse Opoku, M. Rangarajan, A. Gallagher, J. A. C. Sterne, C. R. Reid, H. E. A. Evans e B. Samuelsson. "Attenuation of the Virulence of Porphyromonas gingivalis by Using a Specific Synthetic Kgp Protease Inhibitor". Infection and Immunity 70, n. 12 (dicembre 2002): 6968–75. http://dx.doi.org/10.1128/iai.70.12.6968-6975.2002.

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Abstract (sommario):

ABSTRACT The Arg- and Lys-gingipains of Porphyromonas gingivalis are important virulence determinants in periodontal disease and may correspond to targets for immune- or drug-based treatment strategies. In this investigation we aimed to determine which of these enzymes represents the most promising molecular target for protease inhibitor-based therapy and to examine the effectiveness of the resultant compound in a murine virulence assay. Isogenic mutants with mutations in rgpA and rgpB (encoding Arg-gingipains) and in kgp (encoding Lys-gingipain) and a double mutant with mutations in rgpA and rgpB were prepared by using P. gingivalis W50. The virulence of these mutants indicated that Kgp is a promising drug target. Combinatorial chemistry was used to define the optimal substrate of Kgp, and from this information a specific slowly reversible inhibitor with a nanomolar Ki was designed and synthesized. Growth of P. gingivalis W50 in the presence of this compound resembled the phenotype of the kgp isogenic mutant; in both instances bacterial colonies failed to form pigment on blood agar, and only poor growth was obtained in a defined medium containing albumin as the sole protein source. Furthermore, pretreatment of the wild-type organism with the Kgp inhibitor led to a significant reduction in virulence in the murine assay. These data emphasize the conclusion that Kgp is an important factor for both nutrition and virulence of P. gingivalis and that inhibitors of this enzyme may have therapeutic potential for the control of P. gingivalis infections. Protease inhibitors may be a potentially novel class of antimicrobial agents with relevance to the control of other bacterial pathogens.

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Guthmiller, Janet M., Kaaren G. Vargas, Rupasree Srikantha, Lori L. Schomberg, Paula L. Weistroffer, Paul B. McCray e Brian F. Tack. "Susceptibilities of Oral Bacteria and Yeast to Mammalian Cathelicidins". Antimicrobial Agents and Chemotherapy 45, n. 11 (1 novembre 2001): 3216–19. http://dx.doi.org/10.1128/aac.45.11.3216-3219.2001.

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ABSTRACT The effects of cathelicidins against oral bacteria and clinically important oral yeasts are not known. We tested the susceptibilities of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum,Porphyromonas gingivalis, Streptococcus sanguis, Candida krusei, Candida tropicalis and Candida albicans to the following cathelicidins: FALL39, SMAP29, and CAP18. SMAP29 and CAP18 were antimicrobial, whereas FALL39 did not exhibit antimicrobial activity. Future studies are needed to determine the potential use of these antimicrobial peptides in prevention and treatment of oral infections.

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Kulik, Eva M., Thomas Thurnheer, Lamprini Karygianni, Clemens Walter, Anton Sculean e Sigrun Eick. "Antibiotic Susceptibility Patterns of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis Strains from Different Decades". Antibiotics 8, n. 4 (6 dicembre 2019): 253. http://dx.doi.org/10.3390/antibiotics8040253.

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Abstract (sommario):

The aim of this study was to determine the antibiotic susceptibility patterns of 57 Aggregatibacter actinomycetemcomitans and 56 Porphyromonas gingivalis strains isolated from subgingival biofilm samples of periodontitis patients in Switzerland from 1980 to 2017. The minimal inhibitory concentrations (MIC) of the most commonly used antibiotics in periodontal therapy (amoxicillin, metronidazole, azithromycin, and doxycycline) or in severe body infections (amoxicillin/clavulanic acid, clindamycin, ertapenem, and moxifloxacin) were determined. Furthermore, all the strains were screened for beta-lactamase activity and the presence of selected resistance genes (cfxA, ermF, and tetQ). Overall, there was no significant increase in MIC values over the 37‑year period. Two of the most recent P. gingivalis isolates yielded the highest MIC values. The first isolate was ermF-positive with MIC values >8 µg/mL, 2 µg/mL, and 0.25 µg/mL for clindamycin, azithromycin, and moxifloxacin, respectively. The second isolate showed a high MIC value of 4 µg/mL for moxifloxacin, which was associated with a confirmed single-point mutation in the quinolone resistance-determining region (QRDR) of the gyrA gene. Although there was no significant increase in the antibiotic resistance among the oral bacterial isolates tested, the detection of resistant P. gingivalis isolates underlines the need to optimize the antibiotic therapeutic protocols in dentistry.

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Ślęzak, Paulina, Michał Śmiga, John W. Smalley, Klaudia Siemińska e Teresa Olczak. "Porphyromonas gingivalis HmuY and Streptococcus gordonii GAPDH—Novel Heme Acquisition Strategy in the Oral Microbiome". International Journal of Molecular Sciences 21, n. 11 (10 giugno 2020): 4150. http://dx.doi.org/10.3390/ijms21114150.

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Abstract (sommario):

The oral cavity of healthy individuals is inhabited by commensals, with species of Streptococcus being the most abundant and prevalent in sites not affected by periodontal diseases. The development of chronic periodontitis is linked with the environmental shift in the oral microbiome, leading to the domination of periodontopathogens. Structure-function studies showed that Streptococcus gordonii employs a “moonlighting” protein glyceraldehyde-3-phosphate dehydrogenase (SgGAPDH) to bind heme, thus forming a heme reservoir for exchange with other proteins. Secreted or surface-associated SgGAPDH coordinates Fe(III)heme using His43. Hemophore-like heme-binding proteins of Porphyromonas gingivalis (HmuY), Prevotella intermedia (PinO) and Tannerella forsythia (Tfo) sequester heme complexed to SgGAPDH. Co-culturing of P. gingivalis with S. gordonii results in increased hmuY gene expression, indicating that HmuY might be required for efficient inter-bacterial interactions. In contrast to the ΔhmuY mutant strain, the wild type strain acquires heme and forms deeper biofilm structures on blood agar plates pre-grown with S. gordonii. Therefore, our novel paradigm of heme acquisition used by P. gingivalis appears to extend to co-infections with other oral bacteria and offers a mechanism for the ability of periodontopathogens to obtain sufficient heme in the host environment. Importantly, P. gingivalis is advantaged in terms of acquiring heme, which is vital for its growth survival and virulence.

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30

Brzezińska-Błaszczyk, Ewa, Elżbieta Pawłowska, Tomasz Płoszaj, Henryk Witas, Urszula Godzik e Justyna Agier. "Presence of archaea and selected bacteria in infected root canal systems". Canadian Journal of Microbiology 64, n. 5 (maggio 2018): 317–26. http://dx.doi.org/10.1139/cjm-2017-0531.

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Abstract (sommario):

Infections of the root canal have polymicrobial etiology. The main group of microflora in the infected pulp is bacteria. There is limited data that archaea may be present in infected pulp tissue. The aim of this study was to check the prevalence of archaea in necrotic root canal samples obtained from patients with primary or post-treatment infection. The prevalence of selected bacteria species (Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Synergistes sp.) in necrotic samples was evaluated as well. Sixty-four samples from root canal were collected for DNA and RNA extraction. A PCR assay based on the 16S rRNA gene was used to determine the presence of archaea and selected bacteria. Of the 64 samples, 6 were analyzed by semiquantitative reverse transcription PCR to estimate expression profiles of 16S rRNA, and another 9 were selected for direct sequencing. Archaea were detected in 48.4% samples. Statistical analysis indicated a negative association in coexistence between archaea and Treponema denticola (P < 0.05; Pearson’s χ2 test). The main representative of the Archaea domain found in infected pulp tissue was Methanobrevibacter oralis. Archaea 16S rRNA gene expression was significantly lower than Synergistes sp., Porphyromonas gingivalis, and Tannerella forsythia (P < 0.05; Student’s t test). Thus, it can be hypothesized that archaea may participate in the endodontic microbial community.

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31

Lewis, Janina P., e Francis L. Macrina. "IS195, an Insertion Sequence-Like Element Associated with Protease Genes in Porphyromonas gingivalis". Infection and Immunity 66, n. 7 (1 luglio 1998): 3035–42. http://dx.doi.org/10.1128/iai.66.7.3035-3042.1998.

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ABSTRACT Porphyromonas gingivalis is recognized as an important etiologic agent in adult and early-onset periodontal disease. Proteases produced by this organism contribute to its virulence in mice. Protease-encoding genes have been shown to contain multiple copies of repeated nucleotide sequences. These conserved sequences have also been found in hemagglutinin genes. In the process of studying the genetic loci containing the conserved repeated sequences, we have characterized a prtP gene homolog from P. gingivalis W83 encoding a cysteine protease with Lys-X specificity. However, thisprtP gene was interrupted by an insertion sequence-like element which we designated IS195. Furthermore, IS195 and another element, IS1126, were present downstream of prtP gene homologs (kgp) found inP. gingivalis H66 and 381. IS195, a 1,068-bp insertion sequence-like element, contained 11-bp inverted repeats at its termini and was bordered by 9-bp direct repeats presumed to be a transposition-mediated target site duplication. Its central region contained one large open reading frame encoding a predicted 300-amino-acid protein which appeared to be a transposase. We isolated two naturally occurring variants of P. gingivalis W83, one carrying IS195 within the coding region of theprtP gene and another containing an intact prtPgene. Biochemical characterization revealed a lack of trypsin-like Lys-X specific proteolytic activity in the P. gingivalisW83 variant carrying the disrupted prtP gene. Studies using a mouse model revealed a reduction of virulence resulting from insertion of IS195 into the coding region of theprtP gene. An allelic-exchange mutant defective in theprtP gene also was constructed and tested in vivo. It displayed intermediate virulence compared to that of the wild-type andprtP::IS195 mutant strains. We conclude that the Lys-X cysteine protease contributes to virulence in soft tissue infections.

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32

M. M. Al-Rawi, Amera. "Detection of Porphyromonas gingivalis from Periodontal Pocket Infections by Microbial Cultivation and PCR Techniques". Rafidain Journal of Science 23, n. 2 (1 marzo 2012): 39–55. http://dx.doi.org/10.33899/rjs.2012.27971.

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33

Yu, Wen-Han, Han Hu, Qingde Zhou, Yu Xia e Salomon Amar. "Bioinformatics Analysis of Macrophages Exposed to Porphyromonas gingivalis: Implications in Acute vs. Chronic Infections". PLoS ONE 5, n. 12 (23 dicembre 2010): e15613. http://dx.doi.org/10.1371/journal.pone.0015613.

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34

Loos, B. G., D. W. Dyer, T. S. Whittam e R. K. Selander. "Genetic structure of populations of Porphyromonas gingivalis associated with periodontitis and other oral infections." Infection and Immunity 61, n. 1 (1993): 204–12. http://dx.doi.org/10.1128/iai.61.1.204-212.1993.

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35

Ramalingam, Ashwin Kumar, Smiline Girija Aseervatham Selvi e Vijayashree Priyadharsini Jayaseelan. "Targeting prolyl tripeptidyl peptidase from Porphyromonas gingivalis with the bioactive compounds from Rosmarinus officinalis". Asian Biomedicine 13, n. 5 (4 giugno 2020): 197–203. http://dx.doi.org/10.1515/abm-2019-0061.

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Abstract (sommario):

AbstractBackgroundComplications in periodontitis and other systemic infections related to Porphyromonas gingivalis poses a serious impediment in the treatment process. This leads to the search of novel target proteins to develop newer drugs against P. gingivalis. Prolyl tripeptidyl peptidase (ptp-A) seem to be a vital protein in P. gingivalis virulence and can be a good target for the novel natural bioactive compounds.ObjectivesTo explore the inhibitory potential of Rosmarinus officinalis biocompounds against the ptp-A of P. gingivalis.MethodsThree-dimensional structure of ptp-A was retrieved from the Protein Data Bank with further optimization of both the protein and ligands. In silico inhibitory potential of the selected ligands against ptp-A was done by AutoDock 2.0 and was visualized with Biovia discovery studio visualizing tool with the assessment of the molecular properties of the ligands against ptp-A by molinspiration calculations and drug likeliness.ResultsHigh ptp-A inhibitory effect was observed using rosmarinic acid and luteolin with a bonding energy of −9.81 kcal/mol with 10 hydrogen bond interactions and −9.99 kcal/mol with 7 hydrogen bond interactions, respectively. Carnosic acid and p-coumaric acid showed a binding energy of −7.14 kcal/mol and −6.34 kcal/mol, respectively, with 5 hydrogen bond interactions. Molinspiration assessments showed R. officinalis compounds as the best drug candidates with the topological polar surface area scores <140 Å toward the best oral bioavailability.ConclusionThe carnosic acid, rosmarinic acid, p-coumaric acid, and luteolin from R. officinalis seem to possess a promising inhibitory effect against ptp-A of Candida albicans suggesting ptp-A as the best target to combat P. gingivalis with further in vivo validation.

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36

Fani, Mohammadmehdi, e Jamshid Kohanteb. "In Vitro Antimicrobial Activity of Thymus vulgaris Essential Oil Against Major Oral Pathogens". Journal of Evidence-Based Complementary & Alternative Medicine 22, n. 4 (11 aprile 2017): 660–66. http://dx.doi.org/10.1177/2156587217700772.

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Abstract (sommario):

The objective of present investigation was to determine antimicrobial activity of Thymus vulgaris oil on some oral pathogens. Thymus vulgaris oil was prepared by hydrodistillation and tested against 30 clinical isolates of each of Streptococcus pyogenes, Streptococcus mutans, Candida albicans, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans, prepared from related oral infections using agar disk diffusion and broth microdilution methods. Thymus vulgaris oil at concentrations of 16 to 256 μg/mL exhibited strong inhibitory activity on all clinical isolates producing inhibition zones of 7.5 to 42 mm as measured by agar disk diffusion method. Streptococcus pyogenes and Streptococcus mutans were the most sensitive isolates with minimum inhibitory concentrations of 1.9 and 3.6 μg/mL, respectively. The minimum inhibitory concentration values for C albicans, A actinomycetemcomitans, and P gingivalis were 16.3, 32, and 32 μg/mL, respectively.

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37

GOMES, B., F. MONTAGNER, R. JACINTO, A. ZAIA, C. FERRAZ e F. SOUZAFILHO. "Polymerase Chain Reaction of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in Primary Endodontic Infections". Journal of Endodontics 33, n. 9 (settembre 2007): 1049–52. http://dx.doi.org/10.1016/j.joen.2007.05.017.

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38

Mättö, J., S. Asikainen, M. ‐L Väisänen, M. Rautio, M. Saarela, P. Summanen, S. Finegold e H. Jousimies‐Somer. "Role of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens in Extraoral and Some Odontogenic Infections". Clinical Infectious Diseases 25, s2 (settembre 1997): S194—S198. http://dx.doi.org/10.1086/516205.

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39

Rôças, Isabela N., José F. Siqueira, Kátia R. N. Santos, Ana M. A. Coelho e Rio de Janeiro. "“Red complex” (Bacteroides forsythus, Porphyromonas gingivalis, and Treponema denticola ) in endodontic infections: A molecular approach". Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 91, n. 4 (aprile 2001): 468–71. http://dx.doi.org/10.1067/moe.2001.114379.

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40

Zhao, Xue, Peng Wan, Hongyan Wang, Shuwei Zhang, Jingbo Liu, Chunrong Chang, Ke Yang e Yaping Pan. "An Antibacterial Strategy of Mg-Cu Bone Grafting in Infection-Mediated Periodontics". BioMed Research International 2020 (28 agosto 2020): 1–9. http://dx.doi.org/10.1155/2020/7289208.

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Abstract (sommario):

Periodontal diseases are mainly the results of infections and inflammation of the gum and bone that surround and support the teeth. In this study, the alveolar bone destruction in periodontitis is hypothesized to be treated with novel Mg-Cu alloy grafts due to their antimicrobial and osteopromotive properties. In order to study this new strategy using Mg-Cu alloy grafts as a periodontal bone substitute, the in vitro degradation and antibacterial performance were examined. The pH variation and Mg2+ and Cu2+ release of Mg-Cu alloy extracts were measured. Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), two common bacteria associated with periodontal disease, were cultured in Mg-Cu alloy extracts, and bacterial survival rate was evaluated. The changes of bacterial biofilm and its structure were revealed by scanning electron microscopy (SEM) and transmission electronic microscopy (TEM), respectively. The results showed that the Mg-Cu alloy could significantly decrease the survival rates of both P. gingivalis and A. actinomycetemcomitans. Furthermore, the bacterial biofilms were completely destroyed in Mg-Cu alloy extracts, and the bacterial cell membranes were damaged, finally leading to bacterial apoptosis. These results indicate that the Mg-Cu alloy can effectively eliminate periodontal pathogens, and the use of Mg-Cu in periodontal bone grafts has a great potential to prevent infections after periodontal surgery.

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41

Foschi, F., J. Izard, H. Sasaki, V. Sambri, C. Prati, R. Müller e P. Stashenko. "Treponema denticola in Disseminating Endodontic Infections". Journal of Dental Research 85, n. 8 (agosto 2006): 761–65. http://dx.doi.org/10.1177/154405910608500814.

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Treponema denticola is a consensus periodontal pathogen that has recently been associated with endodontic pathology. In this study, the effect of mono-infection of the dental pulp with T. denticola and with polymicrobial "red-complex" organisms (RC) ( Porphyromonas gingivalis, Tannerella forsythia, and T. denticola) in inducing disseminating infections in wild-type (WT) and severe-combined-immunodeficiency (SCID) mice was analyzed. After 21 days, a high incidence (5/10) of orofacial abscesses was observed in SCID mice mono-infected with T. denticola, whereas abscesses were rare in SCID mice infected with the red-complex organisms or in wild-type mice. Splenomegaly was present in all groups, but only mono-infected SCID mice had weight loss. T. denticola DNA was detected in the spleen, heart, and brain of mono-infected SCID mice and in the spleen from mono-infected wild-type mice, which also had more periapical bone resorption. The results indicate that T. denticola has high pathogenicity, including dissemination to distant organs, further substantiating its potential importance in oral and linked systemic conditions.

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Nibali, L., D. R. Ready, M. Parkar, P. M. Brett, M. Wilson, M. S. Tonetti e G. S. Griffiths. "Gene Polymorphisms and the Prevalence of Key Periodontal Pathogens". Journal of Dental Research 86, n. 5 (maggio 2007): 416–20. http://dx.doi.org/10.1177/154405910708600505.

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Abstract (sommario):

Growing evidence suggests that individual genetic susceptibility may influence the host’s response to infections. The aim of this project was to study whether gene polymorphisms of inflammatory markers are associated with the presence of viable periodontopathogenic bacteria. We extracted genomic DNA from 45 young adults diagnosed with generalized aggressive periodontitis to study Fc receptors, formyl peptide receptor, Interleukin-6, tumor necrosis factor-α, and vitamin D receptor polymorphisms. The presence and viable numbers of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis were determined by culture, and their identities confirmed by PCR. Multiple logistic regressions revealed that both Fcγ receptor and IL-6 -174 polymorphisms were associated with increased odds of detecting A. actinomycetemcomitans, P. gingivalis, and T. forsythensis after adjustment for age, ethnicity, smoking, and periodontitis extent. These findings support the hypothesis that complex interactions between the microbiota and host genome may be at the basis of susceptibility to aggressive periodontitis.

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Amorim, Crystiane Venditi Gomes do, Carlos Eduardo Aun e Marcia Pinto Alves Mayer. "Susceptibility of some oral microorganisms to chlorhexidine and paramonochlorophenol". Brazilian Oral Research 18, n. 3 (settembre 2004): 242–46. http://dx.doi.org/10.1590/s1806-83242004000300012.

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Abstract (sommario):

Since the use of antimicrobial agents is required in endodontic therapies, this study aimed at determining the minimum inhibitory concentrations (MICs) of chlorhexidine digluconate and paramonochlorophenol (PMC) against microorganisms commonly found in endodontic infections. Both agents were tested by agar dilution tests against Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Candida albicans, Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella denticola and Prevotella melaninogenica. The MIC of chlorhexidine ranged from 2.67 to 80.00 µg/ml, and the MIC of PMC from 46.67 to 213.33 µg/ml. The highest MIC value of PMC was detected for E. faecalis whereas E. coli was the most susceptible microorganism to this agent. The highest MIC values of chlorhexidine were observed for P. aeruginosa whereas E. coli and P. denticola were the most susceptible microorganisms to this agent. Since the MIC values observed are much lower than the concentrations currently used in the endodontic therapy, it is suggested that both agents are effective in reducing the microbiota in the root canal.

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O’Connor, Andrew, e Siobhán McClean. "The Role of Universal Stress Proteins in Bacterial Infections". Current Medicinal Chemistry 24, n. 36 (24 novembre 2017): 3970–79. http://dx.doi.org/10.2174/0929867324666170124145543.

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Abstract (sommario):

Universal stress proteins are ubiquitously expressed in bacteria, archaea and plants and other eukaryotes. A general property of USPs is their role in adaptation of bacteria to oxidative stress, high temperature, low pH and/or hypoxia. There is increasing evidence that these proteins facilitate the adaption of bacterial pathogens to the human host environment, thereby facilitating colonisation and pathogenicity. USPs in Mycobacterium tuberculosis are well studied and may play a role in latency of tuberculosis. USP expressed by Acinetobacter baumannii, Listeria monocytogenes and Salmonella enterica serovar Typhimurium are involved in survival in vivo, while USPs expressed in Pseudomonas aeruginosa and Porphyromonas gingivalis are involved in biofilm formation. Burkholderia cepacia complex and Staphylococcus aureus express USPs that play roles in host cell or host protein adhesion. There is also increasing evidence that USPs also bind to antimicrobial agents and may be ideal candidates to target in the future design of new anti-virulence strategies.

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Saito, Daniel, Luiz Lehmann Coutinho, Cristiane Pereira Borges Saito, Siu Mui Tsai, José Francisco Höfling e Reginaldo Bruno Gonçalves. "Real-time Polymerase Chain Reaction Quantification of Porphyromonas gingivalis and Tannerella forsythia in Primary Endodontic Infections". Journal of Endodontics 35, n. 11 (novembre 2009): 1518–24. http://dx.doi.org/10.1016/j.joen.2009.08.005.

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46

Love, Robert M., Malcolm D. McMillan, Yoonsuk Park e Howard F. Jenkinson. "Coinvasion of Dentinal Tubules byPorphyromonas gingivalis and Streptococcus gordonii Depends upon Binding Specificity of Streptococcal Antigen I/II Adhesin". Infection and Immunity 68, n. 3 (1 marzo 2000): 1359–65. http://dx.doi.org/10.1128/iai.68.3.1359-1365.2000.

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Abstract (sommario):

ABSTRACT Cell wall-anchored polypeptides of the antigen I/II family are produced by many species of oral streptococci. These proteins mediate adhesion of streptococci to salivary glycoproteins and to other oral microorganisms and promote binding of cells to collagen type I and invasion of dentinal tubules. Since infections of the root canal system have a mixed anaerobic bacterial etiology, we investigated the hypothesis that coadhesion of anaerobic bacteria with streptococci may facilitate invasive endodontic disease. Porphyromonas gingivalis ATCC 33277 cells were able to invade dentinal tubules when cocultured with Streptococcus gordonii DL1 (Challis) but not when cocultured with Streptococcus mutans NG8. An isogenic noninvasive mutant of S. gordonii, with production of SspA and SspB (antigen I/II family) polypeptides abrogated, was deficient in binding to collagen and had a 40% reduced ability to support adhesion of P. gingivalis. Heterologous expression of the S. mutans SpaP (antigen I/II) protein in this mutant restored collagen binding and tubule invasion but not adhesion toP. gingivalis or the ability to promote P. gingivalis coinvasion of dentin. An isogenic afimbrial mutant ofP. gingivalis had 50% reduced binding to S. gordonii cells but was unaffected in the ability to coinvade dentinal tubules with S. gordonii wild-type cells. Expression of the S. gordonii SspA or SspB polypeptide on the surface of Lactococcus lactis cells endowed these bacteria with the abilities to bind P. gingivalis, penetrate dentinal tubules, and promote P. gingivaliscoinvasion of dentin. The results demonstrate that collagen-binding andP. gingivalis-binding properties of antigen I/II polypeptides are discrete functions. Specificity of antigen I/II polypeptide recognition accounts for the ability of P. gingivalis to coinvade dentinal tubules with S. gordonii but not with S. mutans. This provides evidence that the specificity of interbacterial coadhesion may influence directly the etiology of pulpal and periapical diseases.

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Lisbona-González, Maria Jesús, Esther Muñoz-Soto, Candela Reyes-Botella, Maria Victoria Olmedo-Gaya, Javier Diaz-Castro e Jorge Moreno-Fernandez. "Study of the Antimicrobial Effect of an Ethanolic Extract of Propolis in Periodontal Disease". Applied Sciences 11, n. 16 (13 agosto 2021): 7463. http://dx.doi.org/10.3390/app11167463.

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Abstract (sommario):

Periodontal disease encompasses gingivitis and periodontitis and is one of the most common chronic infections in the adult population. This study aimed to evaluate the influence of Spanish propolis extract (EEP) on the effect of the clinical and microbiological parameters as an adjuvant to scaling and root planning in patients undergoing supportive periodontal therapy (SPT). Forty chronic periodontitis patients were randomly assigned into two groups for the treatment. In the control group (n = 20), the sites were treated by scaling and root planing followed by gingival irrigation with physiological saline and in the test group (n = 20), the sites were treated by scaling and root planing followed by subgingival placement of EEP. At baseline (BL), bleeding on probing positive (BOP+) sites with probing pocket (PPD) ≥ 4 mm were defined as study sites. Plaque index, PPD, BOP, clinical attachment level (CAL), and subgingival plaque were evaluated at BL and 1 month later. The results showed a significant clinical improvement (p < 0.05) in the PPD, CAL and BOP+ comparing them with BL and one month after the periodontal treatment and a significant reduction (p < 0.05) for Tannerella forsythensis, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola in both groups. In addition, the improvement of clinical parameters was observed with subgingival use of EEP and also statistically significant differences between groups were observed (p < 0.05) such as reductions of BOP+ % and reduced counts of T. forsythensis and P. gingivalis, considered as the “key pathogens” for the periodontal diseases. Our results suggest prophylactic and therapeutic potential for EEP against periodontal diseases, improving clinical parameters, reducing gingival bleeding and decreasing bacterial counts of T. forsythensis and P. gingivalis. The subgingival use of EEP represents a promising modality as an adjuvant in periodontal therapy to avoid microbial resistance and other adverse effects.

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48

Rahim, Muhammad Imran, Andreas Winkel, Stefan Lienenklaus, Nico S. Stumpp, Szymon P. Szafrański, Nadine Kommerein, Elmar Willbold et al. "Non-Invasive Luciferase Imaging of Type I Interferon Induction in a Transgenic Mouse Model of Biomaterial Associated Bacterial Infections: Microbial Specificity and Inter-Bacterial Species Interactions". Microorganisms 8, n. 10 (21 ottobre 2020): 1624. http://dx.doi.org/10.3390/microorganisms8101624.

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The performance of biomaterials is often compromised by bacterial infections and subsequent inflammation. So far, the conventional analysis of inflammatory processes in vivo involves time-consuming histology and biochemical assays. The present study employed a mouse model where interferon beta (IFN-β) is monitored as a marker for non-invasive rapid detection of inflammation in implant-related infections. The mouse model comprises subcutaneous implantation of morphologically modified titanium, followed by experimental infections with four taxonomically diverse oral bacteria: Streptococcus oralis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Treponema denticola (as mono culture or selected mixed-culture). IFN-β expression increased upon infections depending on the type of pathogen and was prolonged by the presence of the implant. IFN-β expression kinetics reduced with two mixed species infections when compared with the single species. Histological and confocal microscopy confirmed pathogen-specific infiltration of inflammatory cells at the implant-tissue interface. This was observed mainly in the vicinity of infected implants and was, in contrast to interferon expression, higher in infections with dual species. In summary, this non-invasive mouse model can be used to quantify longitudinally host inflammation in real time and suggests that the polymicrobial character of infection, highly relevant to clinical situations, has complex effects on host immunity.

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Oscarsson e Johansson. "Comment from the Editor to the Special Issue: “Periodontitis: From Dysbiotic Microbial Immune Response to Systemic Inflammation”". Journal of Clinical Medicine 8, n. 10 (16 ottobre 2019): 1706. http://dx.doi.org/10.3390/jcm8101706.

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The human oral cavity contains a large number of different microbial habitats. When microbes from the oral indigenous flora colonize the interspace between the tooth and the connective tissue, they induce an inflammatory response. If the microbes are in sufficient numbers, and release components that cause an imbalance in the host inflammatory response, degenerative processes in the surrounding tissues are induced, ultimately resulting in periodontal disease. The disease progress depends on bacterial load, the composition of the microbial community, and host genetic factors. The two most studied periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans express virulence factors, including proteases and exotoxins. Periodontal infections are also linked to the risk pattern of several systemic diseases. We would like to shed light on the mechanisms behind periodontitis and the associations of periodontal infections with systemic inflammation. Seven articles are included in this Special Issue and cover several pathogenic processes in the periodontal infection with capacity to cause imbalance in the host response. Highlights from each of the published papers are summarized and discussed below.

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Vickerman, M. M., K. A. Brossard, D. B. Funk, A. M. Jesionowski e S. R. Gill. "Phylogenetic analysis of bacterial and archaeal species in symptomatic and asymptomatic endodontic infections". Journal of Medical Microbiology 56, n. 1 (1 gennaio 2007): 110–18. http://dx.doi.org/10.1099/jmm.0.46835-0.

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Phylogenetic analysis of bacterial and archaeal 16S rRNA was used to examine polymicrobial communities within infected root canals of 20 symptomatic and 14 asymptomatic patients. Nucleotide sequences from ∼750 clones amplified from each patient group with universal bacterial primers were matched to the Ribosomal Database Project II database. Phylotypes from 37 genera representing Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria were identified. Results were compared to those obtained with species-specific primers designed to detect Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas endodontalis, Peptostreptococcus micros, Enterococcus sp., Streptococcus sp., Fusobacterium nucleatum, Tannerella forsythensis and Treponema denticola. Since members of the domain Archaea have been implicated in the severity of periodontal disease, and a recent report confirms that archaea are present in endodontic infections, 16S archaeal primers were also used to detect which patients carried these prokaryotes, to determine if their presence correlated with severity of the clinical symptoms. A Methanobrevibacter oralis-like species was detected in one asymptomatic and one symptomatic patient. DNA from root canals of these two patients was further analysed using species-specific primers to determine bacterial cohabitants. Trep. denticola was detected in the asymptomatic but not the symptomatic patient. Conversely, Porph. endodontalis was found in the symptomatic but not the asymptomatic patient. All other species except enterococci were detected with the species-specific primers in both patients. These results confirm the presence of archaea in root canals and provide additional insights into the polymicrobial communities in endodontic infections associated with clinical symptoms.

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