Anaerobic Periodontal Pathogens Research Articles

Formulation and evaluation of herbal gel containing ethanolic extract of Momordica charantia against socransky’s periodontal pathogens of the oral cavity-an in vitro study

Background: Periodontitis is a multifaceted disease initiated by periodontal pathogens which when left untreated results in inflammation of the supporting tissues of the teeth, resorption of alveolar bone, loss of the periodontal ligament attachment, periodontal pocket formation and/or recession of the gingiva. Hence, the current study aimed at evaluating the efficacy of Momordica charantia leaves extract on Socransky’s periodontal pathogens and formulating a herbal gel for subgingival local drug delivery for the potential treatment of moderate periodontitis. Methods: M. charantia leaves were authenticated from a recognized taxonomist. They were coarsely powdered following which an ethanol-based extract preparation was done. The extract obtained was then assessed for minimum inhibitory concentration, minimum bactericidal concentration followed by gel formulation which was then subjected to time kill assay and zone of inhibition on periodontal pathogens, the efficacy of which was comparatively evaluated against 0.12% chlorhexidine (CHX) gluconate. Kruskal-Wallis Test was employed with the statistical significance set at p≤0.05. Results: The concentration of M. charantia ethanolic extract against periodontal pathogens was determined to be 1 gm/100 ml and a statistically significant difference was found in the effectiveness between the gel so formulated and CHX. Conclusion: The antibacterial activity was evident in the ethanolic extract of M. charantia which when used to formulate a herbal gel against anaerobic periodontal pathogens demonstrated efficacy comparable to that of CHX.

Anaerobic Microbiological study of periodontitis in Salah Al – Deen City

Oral flora responsible for periodontal disease is polymorphic. The periodontal infection results either from the penetration of pathogenic microorganisms in the tissues, or even the activation of already existing germs, but not pathogenic under normal conditions. The aims of this study was carried out to evaluate selected bacterial agent s causing periodontitis. One hundred eighty samples were examined in the present study. Clinical measurements of per iodontal parameters used included dental plaque index, gingival index, bleeding on probing, probing pocket depth and clinical attachment loss. The results of periodontitis were the most comm on anaerobic periodontal bacteria isolated from patients were pe ptostreptococcus prevotii which represented 15(8.3%) isolates, while prevotella intermedia, prevotella melani, prevotella disiens, Bifidobacterium sp., Fusibacterium mortiferum peptostreptococcus tet radius, and Wolinella sp. represented only 1 (0.5%) isolates.Also another anaerobic subgingival bacteria isolated from inflamed sites in patients were fusibacterium varium ,vellionella sp., campylobacter gracilis, capnocytophaga sp. ,peptostreptococcus magnus, peptostreptococcus micros, peptostreptococcus niger,peptostreptococcus anaerobius, staphylococcus saccharolyticus, streptococcus consellatus, and gemella morbillorum. Concerning to the results of this study the researcher concludes peptostreptococcus prevotii, prevotella intermedia, prevotella melani, prevotella disiens, Bifidobacterium sp., Fusibacterium mortiferum peptostreptococcus tetradius, and Wolinella sp. fusibacterium varium ,vellionella sp., campylobacter gracilis, capnocytophaga sp. ,peptostreptococcus magnus,eptostreptococcus micros, peptostreptococcus niger,peptostreptococcus anaerobius, staphylococcus saccharolyticus, streptococcus consellatus, and gemella morbillorum were the most common anaerobic periodontal pathogens isolated from patients in the present study.

Porphyromonas gingivalis suppresses oral squamous cell carcinoma progression by inhibiting MUC1 expression and remodeling the tumor microenvironment.

Bacteria are the causative agents of various infectious diseases; however, the anti-tumor effect of some bacterial species has attracted the attention of many scientists. The human oral cavity is inhabited by abundant and diverse bacterial communities and some of these bacterial communities could play a role in tumor suppression. Therefore, it is crucial to find oral bacterial species that show anti-tumor activity on oral cancers. In the present study, we found that a high abundance of Porphyromonas gingivalis, an anaerobic periodontal pathogen, in the tumor microenvironment (TME) was positively associated with the longer survival of patients with oral squamous cell carcinoma (OSCC). An in vitro assay confirmed that P. gingivalis accelerated the death of OSCC cells by inducing cell cycle arrest at the G2/M phase, thus exerting its anti-tumor effect. We also found that P. gingivalis significantly decreased tumor growth in a 4-nitroquinoline-1-oxide-induced in situ OSCC mouse model. The transcriptomics data demonstrated that P. gingivalis suppressed the biosynthesis of mucin O-glycan and other O-glycans, as well as the expression of chemokines. Validation experiments further confirmed the downregulation of mucin-1 (MUC1) and C-X-C motif chemokine 17 (CXCL17) expression by P. gingivalis treatment. Flow cytometry analysis showed that P. gingivalis successfully reversed the immunosuppressive TME, thereby suppressing OSCC growth. In summary, the findings of the present study indicated that the rational use of P. gingivalis could serve as a promising therapeutic strategy for OSCC.

Peran photodynamic therapy dalam perawatan periodontal non-bedah

Introduction: The main of non-surgical periodontal treatment is mechanical debridement. However, the treatment success rate is greatly influenced by ease of mechanical instrument access. Therefore, adjunctive antimicrobial therapy is indicated for complete removal of periodontal pathogen. Since long term systemic antimicrobial treatment can cause resistency, local antimicrobial treatment such as photodynamic therapy may serve as a better choice. Literature review: Photodynamic therapy (PDT) consists of 3 elements: photosensitizer, oxygen, and visible light. After photosensitizer binds with target cells, they are activated by visible light with suitable wavelength, thus producing singlet oxygen and Reactive Oxygen Species (ROS) to create toxic environment for anaerobic periodontal pathogen. PDT increases clinical attachment gain in both chronic and aggressive periodontitis treatment. It also decreases bleeding on probing and pocket depth. Discussion: The advantages of PDT are non invasive, short treatment time required, and reduced possibility of antimicrobial resistency. The disadvantages of PDT are tissue thermogenesis effect and temporary pigmentation of gingiva by photosensitizer. Several precautions should be made while using PDT such as adequate eye protection, irrigation, and isolation. Conclusion: Combination of mecahnical debridement and PDT is proven effective to increase clinical parameters and decrease bacterial burden in peridontitis treatment.

EFFECT OF REMOVABLE DENTURES ON COLONIZATION OF AEROBIC BACTERIA IN THE ORAL CAVITY AND ANTIBIOTIC PATTERN OF THE COMMON ISOLATED BACTERIA

Background and aims: Wearing a removable dental prosthesis causes a change in the micro flora of the mouth. The aim of this research was to verify the composition of aerobic bacterial in the oral cavity of patients with removable dentures and with normal teeth (without dentures), and antibiotics pattern for common isolates. Methods: Bacteriological investigations were performed in 122 individuals (61 removable dentures: 61 normal teeth) attending dental clinics of Faculty of dentistry, Sana’a University, Yemen and private dental clinics. The culturing and antibiotic sensitivity were conducted in the Microbiology Department of the National Center of Public Health Laboratories (NCPHL) Sana'a, Yemen. Tongue dorsa and palate mucosa swabs were collected from normal teeth and denture groups, and as well swabs from mucosal part of denture surfaces in prosthetic patients. Cultivation in microaerophilic (5% CO2) and oxygenic conditions were performed on solid selective and non-selective media in addition to media enriched with 5% blood. Results: Regarding the prosthetic patients, the rate of bacterial isolates from the palate, back, tongue and dental plaque smears was higher potential pathogenic bacteria as S. aureus and Enterobacteriaceae spp in denture wearers, as E. coli (6.6% in dentures vs. 1.6% in the absence of dentures), Klebsiella pneumoniae (11.4% in dentures versus 1.6% in the normal teeth) and Pseudomonas aeruginosa (13.1% versus 0.0% ).While in viridians Streptococcus including Strept .mutans, there was a lower colonization rate in denture patients (18% in palate verses, 73.8% in individuals without dentures). Conclusion: The study demonstrated an elevated rate of bacterial isolates from palate, back, tongue and plaque swabs in denture patients of pathogenic bacteria such as S. aureus, E. coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa; while in Streptococcus viridians including S. mutans, there was a lower colonization rate in denture patients verses a very high rate in individuals without dentures. Peer Review History: Received: 7 November 2022; Revised: 13 December; Accepted: 8 January 2023, Available online: 15 January 2023 Academic Editor: Ahmad Najib, Universitas Muslim Indonesia, Indonesia, ahmad.najib@umi.ac.id Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Dr. Alfonso Alexander Aguileral, University of Veracruz, Mexico, aalexander_2000@yahoo.com Dr. A.A. Mgbahurike, University of Port Harcourt, Nigeria, amaka_mgbahurike@yahoo.com Similar Articles: ETIOLOGY AND RISK FACTORS OF STOMATITIS AMONG YEMENI DENTURE WEARERS PREVALENCE AND ASSOCIATED FACTORS OF ORAL NON-CANDIDA ALBICANS CANDIDA CARRIAGE IN DENTURE WEARERS IN SANA'A CITY- YEMEN THE EFFECT OF NANOSILVER AND CHLORHEXIDINE MOUTHWASH ON ANAEROBIC PERIODONTAL PATHOGENS COUNTS

Assessment of potential antimicrobial activity of Ocimum basilicum extract and chlorhexidine against Socransky's complex pathogens of oral cavity: An in vitro study.

Periodontitis is a multifactorial disease initiated by periodontal pathogens and progresses further in destruction of periodontium. Hence, the objective of this study was to test the efficacy of Ocimum basilicum seeds extract on periodontal pathogens. O. basilicum seeds were authenticated from a recognized taxonomist. They were coarsely powdered; ethanol-based extract preparation was done by the Soxhlet method and aqueous-based extract by hot infusion procedure. Extracts so obtained were assessed for minimum inhibitory concentration, minimum bactericidal concentration, zone of inhibition, and time-kill assay of O. basilicum seeds extract on periodontal pathogens, and comparatively evaluated the effectiveness against 0.12% chlorhexidine (CHX) gluconate in triplicates. Kruskal-Wallis Test was employed wherein the statistical significance was set at P ≤ 0.05. The concentration of O. basilicum ethanolic extract against periodontal pathogens was determined to be 10 mg/ml, whereas 4.7 mg/ml of aqueous extract was proven effective against periodontal pathogens. Similarly, aqueous extract of O. basilicum developed a wider zone against periodontal pathogens compared to ethanol-based O. basilicum extract. Statistically significant difference found in the effectiveness between both extract and CHX. The antibacterial activity was evident in both the extracts of O. basilicum against anaerobic periodontal pathogens. However, it was more pronounced in aqueous extract, but lower compared to CHX.

INTERLEUKIN-1β LEVELS IN THE HUMAN GINGIVAL SULCUS: RATES AND FACTORS AFFECTING ITS LEVELS IN HEALTHY SUBJECTS

Background and objective: Gingival crevicular fluid (GCF) affords a exceptional window for investigation of periodontal condition as the levels of inflammatory mediators, which consequences owing to the increased local destruction of connective tissue structural elements. This study aimed to explore the interleukin 1β (IL-1β)) levels in the human gingival sulcus in healthy normal people; and the effect of host factors as age , gender, type of tooth used in pro-inflammatory biomarkers. Methods: Eighty seven patients, 54 (62.1%) female and 33 (37.9%) male (aged 12–34 years; mean 19.58±4.4 years), participated in this study. Each subject underwent a session on professional oral hygiene and received oral hygiene instructions. Gingival crevicular fluid (GCF) sampling was conducted (baseline). GCF was collected from the Central incisor, the Lateral incisor, the Canine, the First premolar and the second premolar in this study. Results: In total, the mean±SD of central incisor IL-1β was 32.16±4.83 pg/ml, with a mode equal to 28.01 pg/mL, the median was 32.71 pg/mL, and ranged from 20.98 to 41.25 pg/ml with the 75% interquartile range (IQR) equal to 35.94 pg/ml. For males the mean±SD of central incisor IL-1β was 31.6±5.51 pg/ml VS 32.5±4.4 pg/ml of females. For the lateral incisor, canine, first premolar, second premolar: Conclusion: This study provides the upper limit of normal values ​​for interleukin 1β (IL-1β) levels for subjects aged 12–34 years in the GCF. These upper limits of normal values ​​will guide dentists in Yemen when they consider the diagnosis of periodontal disease, as well as its role during orthodontic tooth movement where they play important role in osteocyte activities (e.g, osteoclasts and osteoblasts), and will provide useful baseline data for future studies of interventions against periodontal disease, and teeth movement by orthodontics appliances, in Yemen. Peer Review History: Received: 1 September 2022; Revised: 11 October; Accepted: 6 November, Available online: 15 November 2022 Academic Editor: Dr. Emmanuel O. Olorunsola, Department of Pharmaceutics & Pharmaceutical Technology, University of Uyo, Nigeria, olorunsolaeo@yahoo.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 5.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Dr. Rima Benatoui,Laboratory of Applied Neuroendocrinology, Department of Biology, Faculty of Science, Badji Mokhtar University Annaba, Algeria. benattouiryma@gmail.com Dr. Gulam Mohammed Husain,, National Research Institute of Unani Medicine for Skin Disorders, Hyderabad, India, gmhusain@gmail.com Similar Articles: THE EFFECT OF NANOSILVER AND CHLORHEXIDINE MOUTHWASH ON ANAEROBIC PERIODONTAL PATHOGENS COUNTS

Extracellular vesicles derived from the periodontal pathogen Filifactor alocis induce systemic bone loss through Toll-like receptor 2.

Periodontitis is an inflammatory disease induced by local infection in tooth‐supporting tissue. Periodontitis is associated with systemic bone diseases, but little is known about the mechanism of the causal effect of periodontitis on systemic bone resorption. Bacteria‐derived extracellular vesicles (EVs) act as natural carriers of virulence factors that are responsible for systemic inflammation. In this study, we investigated the role of EVs derived from Filifactor alocis, a Gram‐positive, anaerobic periodontal pathogen, in systemic bone loss and osteoclast differentiation. F. alocis EVs accumulated in the long bones of mice after intraperitoneal administration. These EVs induced proinflammatory cytokines, osteoclastogenesis, and bone resorption via Toll‐like receptor 2 (TLR2). The phase separation of F. alocis EVs showed that amphiphilic molecules were responsible for the induced bone resorption and osteoclastogenesis. The osteoclastogenic effects of F. alocis EVs were reduced by lipoprotein lipase. Proteomic analysis of the amphiphilic molecules identified seven lipoproteins. Our results indicate that lipoprotein‐like molecules in F. alocis EVs may contribute to systemic bone loss via TLR2.

Comparison of Time-kill Assay to Evaluate the Antimicrobial Efficacy of Garlic (Allium sativum) and Guava (Psidium guajava) Extracts on Periodontal Pathogens.

Background:The role of Gram-negative anaerobic periodontal pathogens in periodontal diseases has led to the loss of tooth-supporting structures. These diseases can be prevented by the inhibition of bacterial biofilm on the tooth surfaces. Many treatment modalities have been tried to prevent periodontal diseases. With the rise in resistance to synthetic antimicrobials, there is a requirement to develop natural antimicrobials for the control of periodontitis.Aim:The aim of the study was to evaluate and compare the efficacy of garlic (Allium sativum) and guava (Psidium guajava) extracts on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans using time-kill assay.Materials and Methods:Aqueous garlic extract (AGaE), ethanolic garlic extract (EGaE), aqueous guava extract (AGuE), and ethanolic guava extract (EGuE) were prepared. Time-kill assays were performed on P. gingivalis and A. actinomycetemcomitans. The aqueous and ethanolic extracts of guava and garlic were compared to assess the maximum bactericidal potency.Results:The comparison of time-kill assay of AGaE and AGuE on P. gingivalis showed a statistically significant difference at 2 h (t = 5.29, P < 0.01), 4 h (t = −4.867, P < 0.01), and 6 h (t = −3.647, P < 0.001). The comparison of time-kill assay of EGaE and EGuE on A. actinomycetemcomitans showed a statistically significant difference at 2 h (t = 4.54, P < 0.01) and highly significant difference at 4 h (t = 6.57, P < 0.001).Conclusions:The, judicious use of these phytomedicinal products could be cost-effective and also the adverse effects caused due to the long-term usage of synthetic antimicrobials can be avoided.

Identification and characterization of a UbK family kinase in Porphyromonas gingivalis that phosphorylates the RprY response regulator

Phosphorylation of proteins is a key component of bacterial signaling systems that can control important functions such as community development and virulence. We report here the identification of a Ubiquitous bacterial Kinase (UbK) family member, designated UbK1, in the anaerobic periodontal pathogen, Porphyromonas gingivalis. UbK1 contains conserved SPT/S, Hanks-type HxDxYR, EW, and Walker A motifs, and a mutation analysis established the Walker A domain and the Hanks-type domain as required for both autophosphorylation and transphosphorylation. UbK1 autophosphorylates on the proximal serine in the SPT/S domain as well as the tyrosine residue within the HxDxYR domain and the tyrosine residue immediately proximal, indicating both serine/threonine and tyrosine specificity. The orphan two-component system response regulator (RR) RprY was phosphorylated on Y41 in the receiver domain by UbK1. The ubk1 gene is essential in P. gingivalis; however, overexpression of UbK1 showed that UbK1-mediated phosphorylation of RprY functions predominantly to augment its properties as a transcriptional enhancer. These results establish that P. gingivalis possesses an active UbK kinase in addition to a previously described Bacterial Tyrosine family kinase. The RR RprY is identified as the first transcriptional regulator controlled by a UbK enzyme.

ETIOPATHOGENETIC MECHANISMS OF PERIODONTAL DISEASES AGAINST THE BACKGROUND OF VIRAL LIVER DISSEASES

The article presents a review and analysis of relevant available literature sources on etiopathogenetic mechanisms of periodontal disease and liver diseases of viral aetiology, and, in particular, hepatitis B and C viruses. Significant prevalence, pronounced polymorphism of clinical hepatic and extrahepatic manifestations, the incidence rate of liver cirrhosis and hepatocellular carcinoma allows us to consider hepatitis of viral aetiology as a medical and social challenge. Multi-vector liver dysfunctions can cause oral presentations in this group of patients, and in particular, in their periodontal tissues. Viral liver damage is associated with significant impairment of the microbiocenosis in gingival sulcus and periodontal pockets. Dysbiotic changes are characterized by an increase in the number of opportunistic pathogens and anaerobic periodontal pathogens. Exacerbation of dysbiosis along with deterioration of oral hygiene occurs as a consequence of reduced local resistance and hyposalivation due to the sialotropic properties of hepatitis C virus. Significant pathogenetic role in the development of periodontal disease is played by disorders of metabolic and synthetic functions of the liver, as well as hormonal imbalance, metabolic disorders, immune-mediated damage, induction of autoimmune mechanisms and cytokine imbalance. The formation of hepatogenic osteopenia and osteoporosis enhances the loss of bone mass of the alveolar processes in the jaws and, accordingly, the resorption of bone tissue with the further progression of more aggressive forms of generalized periodontitis.

Adhesion of anaerobic periodontal pathogens to extracellular matrix proteins.

Extracellular matrix (ECM) proteins are highly abundant in the human body and can be found in various tissues, most prominently in connective tissue and basement membrane. For invasive bacterial pathogens, these structures function as physical barriers that block access to underlying tissues. The ability to bind and degrade these barriers is important for the establishment of infections and migration to other body sites. In the oral cavity, the ECM and the basement membrane (BM) are important components of the Junctional epithelium (JE) that closes the gap between the teeth surface and the mucosa. In periodontitis, the JE is breached by invading pathogenic bacteria, particularly strict anaerobic species. In periodontitis, invading microorganisms induce an unregulated and destructive host response through polymicrobial synergism and dysbiosis that attracts immune cells and contributes to the destruction of connective tissue and bone in the periodontal pocket. Colonization of the periodontal pocket is the first step to establish this infection, and binding to ECM is a major advantage in this site. Several species of strict anaerobic bacteria are implicated in acute and chronic periodontitis, and although binding to ECM proteins was studied in these species, few adhesins were identified so far, and the mechanisms involved in adhesion are largely unidentified. This review summarizes the data available on the interaction of strict anaerobic bacteria and components of the ECM.

THE EFFECT OF NANOSILVER AND CHLORHEXIDINE MOUTHWASH ON ANAEROBIC PERIODONTAL PATHOGENS COUNTS

The necessitate for frequent application of Chlorhexidine (CHX), and other side effects has encouraged the search for option that are more suitable for patients as nanosilver mouthwash (NS). So the aim of this study was to determine the effects of a mouthwash made with nanosilver on dental plaque microbial counts and compare it with commercially available Chlorhexidine. Sixty-two plaque-induced gingivitis patients were allocated into two groups and asked to rinse with 10 ml of NS and CHX, immediately after brushing, for 1 min, in the morning and evening. Sub gingival plaque microbial counts were taken at baseline, two weeks, and finally at four weeks for each patient. Subsequently, the samples were collected, transferred and cultured in blood agar in anaerobic media. The colonies were counted and expressed as CFUs. The statistical analysis between CFUs variables within groups was calculated and the variation significance was calculated by performed t-test. It is very obvious that the values of CFU decreased significantly (p&lt;0.001) as the time of use nanosilver until reaching the highest value when the time of use was 4 weeks [70.3±47 to 32.4±24.6 (2 weeks), and 14.2±9.9 (4 weeks) with inhibition of growth rate after 2 weeks was 46% and after 4 weeks was 79.7%. The effect of commercially available CHX mouthwash was approximately similar to the effect of NS mouthwash used. In conclusion, both Group I and Group II showed similar effect on inhibition anaerobic periodontal pathogens counts and gingival health. There was significant inhibitory effect on microbial counts where NS mouth-wash had shown better results than CHX, but there was no significant difference between the nanosilver mouth wash and the Chlorhexidine mouthwash.&#x0D; Peer Review History: &#x0D; UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency.&#x0D; Received file &#x0D; &#x0D; Average Peer review marks at initial stage: 5.5/10&#x0D; Average Peer review marks at publication stage: 8.0/10&#x0D; Reviewer(s) detail:&#x0D; Name: Dr. Mohamed Salama&#x0D; Affiliation: Modern University for Technology &amp; Information, Egypt&#x0D; E-mail: salama47@yahoo.com&#x0D; &#x0D; Name: Dr. Tamer Elhabibi&#x0D; Affiliation: Suez Canal University, Egypt&#x0D; E-mail: tamer_hassan@pharm.suez.edu.eg&#x0D; Comments of reviewer(s): &#x0D;

PHOTOTOXIC EFFECT OF VISIBLE BLUE LIGHT ON AGGREGATIBACTER ACTINOMYCETEMCOMITANS AND PORPHYROMONAS GINGIVALIS ISOLATED FROM PATIENTS WITH CHRONIC PERIODENTITIS: AN IN-VITRO EXPERIMENTAL STUDY

Chronic periodentitis is a quite common disease in adult patients characterized by pocket formation and/or recession while progressive loss of periodontal attachment occurs slowly to moderately local risk factors, e.g. bacterial plaque. Wide array of microorganisms have been associated with periodontal disease, out of which Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) have been predominantly associated with periodontal diseases. The objectives of this study were to determine phototoxic effect of visible blue light on Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis clinical isolates from chronic periodentitis patients, and to study their antibiotic sensitivity against selected antibiotics. The test was carried out on 15 strains of Aggregatibacter actinomycetemcomitans and 15 strains of Porphyromonas gingivalis isolated from pockets of chronic periodentitis patients aged between 30-50 years old with pocket depths of 5-6 mm. The bacteria cultured, isolated, and identified by standard bacteriological methods, then subjected to visible blue light at different periods of time exposures. After light exposure, the bacterial killing rates were calculated from colony forming unit (CFU) counts after 48hours of anaerobic incubation. There was a decrease in CFU for both microorganisms as we proceeded from zero, 20, 40 and 60 seconds of blue light exposure. In conclusions, there was a phototoxic effect for the visible blue light emitted from the light curing device against the anaerobic periodontal pathogens and blue light exposure is effective in reducing periodontal pathogens. It is recommended that an adjunctive exogenous photosensitizer be used and that pathogens be exposed to visible light for clinical antimicrobial periodontal therapy.

Potential role of periodontal pathogens in compromising epithelial barrier function by inducing epithelial-mesenchymal transition.

Epithelial-mesenchymal transition (EMT) is a process by which epithelial cells acquire a mesenchymal-like phenotype and this may be induced by exposure to gram-negative bacteria. It has been proposed that EMT is responsible for compromising epithelial barrier function in the pathogenesis of several diseases. However, the possible role of EMT in the pathogenesis of periodontitis has not previously been investigated. The aim of this study therefore was to investigate whether gram-negative, anaerobic periodontal pathogens could trigger EMT in primary oral keratinocytes in vitro. Primary oral keratinocytes were harvested from labial mandibular mucosa of Wistar Han rats. Cells were exposed to heat-killed Fusobacterium nucleatum and Porphyromonas gingivalis (100 bacteria/epithelial cell) and to 20μg/mL of Escherichia coli lipopolysaccharide over an 8-day period. Exposure to bacteria did not significantly change epithelial cell number or vitality in comparison with unstimulated controls at the majority of time-points examined. Expression of EMT marker genes was determined by semiquantitative RT-PCR at 1, 5, and 8days following stimulation. The expression of EMT markers was also assessed by immunofluorescence (E-cadherin and vimentin) and using immunocytochemistry to determine Snail activation. The loss of epithelial monolayer coherence, in response to bacterial challenge, was determined by measuring trans-epithelial electrical resistance. The induction of a migratory phenotype was investigated using scratch-wound and transwell migration assays. Exposure of primary epithelial cell cultures to periodontal pathogens was associated with a significant decrease in transcription (~3-fold) of E-cadherin and the upregulation of N-cadherin, vimentin, Snail, matrix metalloproteinase-2 (~3-5 fold) and toll-like receptor 4. Bacterial stimulation (for 8 days) also resulted in an increased percentage of vimentin-positive cells (an increase of 20% after stimulation with P.gingivalis and an increase of 30% after stimulation with F.nucleatum, compared with controls). Furthermore, periodontal pathogens significantly increased the activation of Snail (60%) and cultures exhibited a decrease in electrical impedance (P<.001) in comparison with unexposed controls. The migratory ability of the cells increased significantly in response to bacterial stimulation, as shown by both the number of migrated cells and scratch-wound closure rates. Prolonged exposure of primary rat oral keratinocyte cultures to periodontal pathogens generated EMT-like features, which introduces the possibility that this process may be involved in loss of epithelial integrity during periodontitis.

Amixicile, a novel strategy for targeting oral anaerobic pathogens

The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate. PFOR is present in these anaerobic pathogenic bacteria and thus we hypothesized that amixicile would effectively inhibit their growth. In general, PFOR is present in all obligate anaerobic bacteria, while oral commensal aerobes, including aerotolerant ones, such as Streptococcus gordonii, use pyruvate dehydrogenase to decarboxylate pyruvate. Accordingly, we observed that growth of the PFOR-containing anaerobic periodontal pathogens, grown in both monospecies as well as multispecies broth cultures was inhibited in a dose-dependent manner while that of S. gordonii was unaffected. Furthermore, we also show that amixicile is effective against these pathogens grown as monospecies and multispecies biofilms. Finally, amixicile is the first selective therapeutic agent active against bacteria internalized by host cells. Together, the results show that amixicile is an effective inhibitor of oral anaerobic bacteria and as such, is a good candidate for treatment of periodontal diseases.

Porphyromonas gingivalis Stimulates TLR2-PI3K Signaling to Escape Immune Clearance and Induce Bone Resorption Independently of MyD88.

Porphyromonas gingivalis is a gram-negative anaerobic periodontal pathogen that persists in dysbiotic mixed-species biofilms alongside a dense inflammatory infiltrate of neutrophils and other leukocytes in the subgingival areas of the periodontium. Toll-like receptor 2 (TLR2) mediates the inflammatory response to P. gingivalis and TLR2-deficient mice resist alveolar bone resorption following oral challenge with this organism. Although, MyD88 is an adaptor protein considered necessary for TLR2-induced inflammation, we now report for the first time that oral challenge with P. gingivalis leads to alveolar bone resorption in the absence of MyD88. Indeed, in contrast to prototypical TLR2 agonists, such as the lipopeptide Pam3CSK4 that activates TLR2 in a strictly MyD88-dependent manner, P. gingivalis strikingly induced TLR2 signaling in neutrophils and macrophages regardless of the presence or absence of MyD88. Moreover, genetic or antibody-mediated inactivation of TLR2 completely reduced cytokine production in P. gingivalis-stimulated neutrophils or macrophages, suggesting that TLR2 plays a non-redundant role in the host response to P. gingivalis. In the absence of MyD88, inflammatory TLR2 signaling in P. gingivalis-stimulated neutrophils or macrophages depended upon PI3K. Intriguingly, TLR2-PI3K signaling was also critical to P. gingivalis evasion of killing by macrophages, since their ability to phagocytose this pathogen was reduced in a TLR2 and PI3K-dependent manner. Moreover, within those cells that did phagocytose bacteria, TLR2-PI3K signaling blocked phago-lysosomal maturation, thereby revealing a novel mechanism whereby P. gingivalis can enhance its intracellular survival. Therefore, P. gingivalis uncouples inflammation from bactericidal activity by substituting TLR2-PI3K in place of TLR2-MyD88 signaling. These findings further support the role of P. gingivalis as a keystone pathogen, which manipulates the host inflammatory response in a way that promotes bone loss but not bacterial clearance. Modulation of these host response factors may lead to novel therapeutic approaches to improve outcomes in disease conditions associated with P. gingivalis.

“Association of periodontopathic anaerobic bacterial co-occurrence to atherosclerosis” – A cross-sectional study

BackgroundEpidemiological studies have shown a link between periodontitis and atherosclerosis. Hence the present study was chosen to assess the presence of eight anaerobic periodontal pathogens and their virulence genes in subgingival plaque (SGP) and atheromatous plaque (AP) of patients with Ischaemic heart disease. MethodsSGP and AP collected from 65 Ischaemic heart disease patients were screened for the presence of periodontal bacterial pathogens by Polymerase chain reaction. The samples positive for Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia were screened for virulence genes. Chronic periodontitis patients (ChP) without any systemic disease (n = 59) and healthy subjects free of both periodontitis and systemic disease were included as control groups (n = 100). Results and discussionStatistical significance was observed for the prevalence of 16S rRNA of P. gingivalis, T. forsythia, T. denticola and P. nigrescens both in SGP and AP. Nine different periodontal bacterial co-occurrences were observed in SGP and AP of Ischaemic heart disease patients. Besides, the prevalence of these nine different bacterial co-occurrence was high in SGP OF Ischaemic heart disease patients compared to ChP without systemic disease. Among the nine different bacterial co-occurrence, only four were observed in SGP of ChP without systemic disease in spite of high prevalence of these anaerobic bacterial species. While, bacterial co-occurrences was completely absent among healthy subjects. Significant odds and risk ratio to atherosclerosis were observed for P. gingivalis, T. forsythia, T. denticola and P. nigrescens. Among the virulence genes, significance to atherosclerosis was observed for P. gingivalis type II fimA and T. forsythia bspA. ConclusionThe results of this study strongly correlate periodontal bacterial co-occurrence and periodontal bacterial adhesion factor to atherosclerosis.

Bone loss and aggravated autoimmune arthritis in HLA-DRβ1-bearing humanized mice following oral challenge with Porphyromonas gingivalis.

BackgroundThe linkage between periodontal disease and rheumatoid arthritis is well established. Commonalities among the two are that both are chronic inflammatory diseases characterized by bone loss, an association with the shared epitope susceptibility allele, and anti-citrullinated protein antibodies.MethodsTo explore immune mechanisms that may connect the two seemingly disparate disorders, we measured host immune responses including T-cell phenotype and anti-citrullinated protein antibody production in human leukocyte antigen (HLA)-DR1 humanized C57BL/6 mice following exposure to the Gram-negative anaerobic periodontal disease pathogen Porphyromonas gingivalis. We measured autoimmune arthritis disease expression in mice exposed to P. gingivalis, and also in arthritis-resistant mice by flow cytometry and multiplex cytokine-linked and enzyme-linked immunosorbent assays. We also measured femoral bone density by microcomputed tomography and systemic cytokine production.ResultsExposure of the gingiva of DR1 mice to P. gingivalis results in a transient increase in the percentage of Th17 cells, both in peripheral blood and cervical lymph nodes, a burst of systemic cytokine activity, a loss in femoral bone density, and the generation of anti-citrullinated protein antibodies. Importantly, these antibodies are not produced in response to P. gingivalis treatment of wild-type C57BL/6 mice, and P. gingivalis exposure triggered expression of arthritis in arthritis-resistant mice.ConclusionsExposure of gingival tissues to P. gingivalis has systemic effects that can result in disease pathology in tissues that are spatially removed from the initial site of infection, providing evidence for systemic effects of this periodontal pathogen. The elicitation of anti-citrullinated protein antibodies in an HLA-DR1-restricted fashion by mice exposed to P. gingivalis provides support for the role of the shared epitope in both periodontal disease and rheumatoid arthritis. The ability of P. gingivalis to induce disease expression in arthritis-resistant mice provides support for the idea that periodontal infection may be able to trigger autoimmunity if other disease-eliciting factors are already present.

Propolis, A Hope for the Future in Treating Resistant Periodontal Pathogens.

Introduction: Periodontitis is one of the most common causes of tooth loss worldwide. Recently, special attention has been paid to natural medication for its treatment. For this purpose, propolis (bee glue) activity has also been investigated. Its antibacterial properties are mainly attributed to flavonones pinocembrin, flavonols galangin and to the caffeic acid phenethyl ester. This study is aimed at evaluating the antimicrobial effects of propolis from Pakistan on 35 clinical isolates of pigmented anaerobic periodontal pathogens.Methods: This study was conducted in the Microbiology department, University of Health Sciences, Lahore, Pakistan. Pathogens included were Porphyromonas asaccharolytica (n=9), Porphyromonas gingivalis (n=13), Prevotella intermedia (n=9), Prevotella melaninogenica (n=4). Minimum inhibitory concentration (MIC) to three antibiotics was obtained by E-test method. All strains were sensitive to amoxicillin plus clavulanic acid and metronidazole, but 100% of P asaccharolytica and P melaninogenica strains displayed intermediate resistance to tetracycline while 69.2% P gingivalis and 100% P intermedia strains exhibited complete resistance to tetracycline. Screening for antibacterial activity of propolis extract was done by agar well diffusion assay, and all strains were found sensitive to ethanolic extract of propolis.Results: MIC was obtained by agar incorporation technique with values ranging from 0.064 to 0.512 mg/ml. It was also noticed that percentage yield of ethanolic extract of propolis prepared from ultrasonic extraction method was higher compared to extract obtained with maceration.Conclusion: These results indicate that propolis from this region has potent antimicrobial activity against pigmented anaerobic periodontal pathogens. Taking into consideration the increasing resistance in anaerobic bacteria, this effective antimicrobial activity of propolis gives hope in the treatment of oral cavity diseases.