Aggregatibacter Actinomycetemcomitans Strains Research Articles

A Comparative Analysis of the Efficacy of Bacterial Lysate versus Antibiotic Therapy in the Treatment of Experimental Peri-Implantitis in Rats.

Peri-implantitis (PI) is a current concern whose understanding and resolution are ongoing. We aimed to evaluate in vivo a new treatment with antibacterial properties, based on bacterial lysates obtained from the strains of Aggregatibacter actinomycetemcomitans, Streptococcus oralis, and Fusobacterium nucleatum. This research was conducted on 30 rats with PI which were divided into three groups and treated with antibiotic and anti-inflammatory (AAi) drugs, bacterial lysates (BLs), and saline (C), respectively. The monitoring period included the clinical and paraclinical examination where hematological, immunological, imaging, and histopathological analysis were performed. No particular clinical signs were observed, but the radiological examination showed the loss of all implants in group C, in contrast to group BL which had the highest survival rate of devices. White cells showed a decrease from the PI period, as did the immunological analysis. Only IL-6 showed an increase in the AAi and BL groups. Histopathologically, the C group presented a high degree of bone destruction, and in the BL group, many attenuated inflammatory phenomena appeared compared to the AAi animals. Bacterial lysates have similar effects to antibiotic-based therapeutic regimens for PI, and their future use may help to improve the current therapeutic management of the disease.

Comparative Evaluation on the effect of Herbal mouthwash on Putative Periodontal Pathogens – In vitro study

Introduction: The architecture of dental plaque biofilms provides a resistant environment for bacteria. Chemical plaque control agents containing antimicrobials (chlorhexidine, herbal mouthwash) are adjunctively used to halt the growth of dental plaque. In order to overcome the adverse effects that result due to the extensive use of synthetic formulation, several herbal preparations have been tested for their effectiveness. In the current study, the effects of chlorhexidine (CHX) and herbal mouthwash in vitro on the planktonic and sessile phases of selected strains of putative periodontal pathogens are compared. Methods: The standard strains of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum were used for assessing the antimicrobial properties of the two mouthwashes. The methods of broth dilution and agar diffusion were used for assessing the minimum inhibitory concentration (MIC) in the planktonic phase. The antimicrobial effects in the sessile phase were determined by crystal violet microtiter assay. Results: The broth dilution method showed no statistical significant difference in MIC between the two mouthwashes. The agar diffusion method showed a statistically significant difference between the two types of mouthwashes against the F. nucleatum. The crystal violet microtiter assay suggested that the herbal mouthwash exhibited an antimicrobial effect even after 24 hrs on a mixed biofilm. Conclusion: Antimicrobial action exerted by the herbal mouthwash after 24 hrs was higher than that of CHX, against a biofilm constituting the three putative periodontal pathogens.

Detection of JP2 and Non-JP2 Genotype Strains of Aggregatibacter Actinomycetemcomitans in Localized Aggressive Periodontitis Patients Among the Egyptian Population

Detection of JP2 and Non-JP2 Genotype Strains of Aggregatibacter Actinomycetemcomitans in Localized Aggressive Periodontitis Patients Among the Egyptian Population

In Vitro Antibacterial Activity of Myrtus communis L. and Marrubium vulgare L. Leaves against Aggregatibacter actinomycetemcomitans and Eikenella corrodens.

Materials and Methods Clinical strains of Aggregatibacter actinomycetemcomitans and Eikenella corrodens and two reference strains of A. actinomycetemcomitans were tested. The antibacterial activity of each studied plant extract was evaluated using agar diffusion and broth microdilution assays. Results Both aqueous and methanolic extracts of M. communis exhibited high antibacterial activity against periodontal pathogens as compared to M. vulgare extracts. At concentrations of 2.5-0.32 mg/disc, inhibition zones of the methanolic extract of M. communis ranged from 19.66 ± 0.57 to 12.33 ± 0.57 mm. The methanolic extract of M. vulgare showed at concentrations of 5-0.63 mg/disc inhibition zones ranging from 15.66 ± 0.57 to 12 ± 0.00 mm. Its aqueous extract at concentration of 0.63 mg/disc showed no antimicrobial activity against the clinical and reference strain of A. actinomycetemcomitans. Conclusion. This study showed that methanolic and aqueous extracts of M. communis and M. vulgare have in vitro an antibacterial activity against periodontal pathogens. They could be use as ingredients of an oral antimicrobial agent for prevention or treatment of periodontal diseases. Further research on isolating the compounds from these plant extracts and their toxicity effect could be conducted.

Etiology of aggressive periodontitis in individuals of African descent.

Aggressive periodontitis (AgP) is a form of periodontitis that affects adolescents and has a significantly higher prevalence in individuals of African descent. AgP typically shows familial aggregation, suggesting a genetic predisposition. Young age, good health status, rapid attachment loss, and familial aggregation are the primary features of this disease. AgP has been closely linked to specific bacterial strains of Aggregatibacter actinomycetemcomitans. A. actinomycetemcomitans strains isolated from patients with AgP produce leukotoxin (LtxA), which specifically affects polymorphonuclear leukocytes in primates, especially humans. High-throughput 16S rRNA gene sequencing and bioinformatics analyses revealed differences in the subgingival microbiota between patients with AgP and those with chronic periodontitis (ChP). The genera Atopobium and Prevotella show increased prevalences in AgP than in ChP. According to AgP susceptibility, several single nucleotide polymorphisms have been detected in different genes in individuals of African descent. Interleukin (IL)-1α and IL-1β genetic polymorphisms may be associated with the severity of both ChP and AgP. An elevated serum level of IL-17 produced by Th17 cells may be a characteristic of AgP. Analyses of the relationships among bacteria, host defenses, genetic predisposition, and numerous other factors are required to understand the progression of this disease.

Residual decontamination chemical agents negatively affect adhesion and proliferation of osteoblast-like cells on implant surface

PurposeTo investigate the influence of implant surface decontaminated and uncontaminated on osteoblast-like cell adhesion and proliferationMaterials and methodsCommercially available implants of different brands and surface characteristics were selected: Biomet 3i® Nanotite (NT) and Osseotite (OT), Straumann® SLActive (SLA), and Neodent® Acqua Drive (ACQ) and Neoporos Drive CM (CM). Physical and chemical properties of the implants were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and wettability analysis (WETT). Implants were previously contaminated with Aggregatibacter actinomycetemcomitans strains; after that, samples were decontaminated by different chemical methods. Decontaminated (test group; n = 15/type of implant) and uncontaminated (control group; n = 5/type of implant) samples were analyzed according to the number of human osteoblastic osteosarcoma cells (Saos-2) adhered on the implant surface after 24 h and 72 h in SEM images.ResultsACQ was found to be highly hydrophilic, and NT was the most hydrophobic implant. Increased variation of Saos-2 cell adhesion and proliferation were observed on all test and control groups. Controversially, at the proliferation analysis in 72 h, CM implant was the only implant that showed no significant difference between test and group (p = 0.2833; Tukey’s multiple comparisons test). NT implants showed the greater value of cell proliferation when compared with all types of implant surface (p = 0.0002; Tukey’s multiple comparisons test).ConclusionsThese findings suggest that decontaminated surfaces were able to impair the counting of osteoblast-like cell adhesion and proliferation.

Comparison of Minimum Inhibitory Concentrations of Hypericum Perforatum L. Essential Oils, 0.2 % Chlorhexidine and 10 % Povidone-iodine Over Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis

Hypericum perforatum is a useful plant because of its biological features, such as bactericidal, virucidal, and fungicidal effects. Elimination of periodontal pathogens, including Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, from the oral environment, is important for the stability of periodontal health. Therefore, we aimed to determine the antimicrobial activity of the Hypericum perforatum L. essential oils over these pathogens using cell cultures. The standard and clinical bacterial strains were used in this study. The essential oils extracted from Hypericum perforatum L. flowers were analyzed with gaschromatography/mass spectrometry. The antimicrobial activities of the essential oils along with 0.2 % chlorhexidine, 10 % povidone-iodine, and combinations of essential oils and 0.2 % chlorhexidine, and essential oils and 10 % povidone-iodine were evaluated by measuring the minimum inhibitory concentrations. Essential oils’ minimum inhibitory concentration value for clinical A. actinomycetemcomitans strains was significantly lower than that of the povidone-iodine solution (P<0.05). However, despite the low minimum inhibitory concentration value of essential oils, when compared to 0.2 % chlorhexidine, there was no statistically significant difference between the agents (P=0.113). For clinical strains of Porphyromonas gingivalis, the essential oils showed a lower minimum inhibitory concentration value compared to chlorhexidine and povidone-iodine. The essential oils combined with chlorhexidine or povidone-iodine showed significantly lower minimum inhibitory concentration value for both strains of Aggregatibacter actinomycetemcomitans (P<0.05). With the lower minimum inhibitory concentration values, the essential oils showed strong antimicrobial activity. Moreover, when combined with chlorhexidine or the povidone-iodine, the antimicrobial effect of essential oils on Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis strains increased synergistically.

Chemical Composition, Antimicrobial activity, in Vitro Cytotoxicity and Leukotoxin Neutralization of Essential Oil from Origanum vulgare against Aggregatibacter actinomycetemcomitans.

In this study, the essential oil of Origanum vulgare was evaluated for putative antibacterial activity against six clinical strains and five reference strains of Aggregatibacter actinomycetemcomitans, in comparison with some antimicrobials. The chemical composition of the essential oil was analyzed, using chromatography (CG) and gas chromatography–mass spectrometry coupled (CG–MS). The major compounds in the oil were Carvacrol (32.36%), α-terpineol (16.70%), p-cymene (16.24%), and Thymol (12.05%). The antimicrobial activity was determined by an agar well diffusion test. A broth microdilution method was used to study the minimal inhibitory concentration (MIC). The minimal bactericidal concentration (MBC) was also determined. The cytotoxicity of the essential oil (IC50) was <125 µg/mL for THP-1 cells, which was high in comparison with different MIC values for the A. actinomycetemcomitans strains. O. vulgare essential oil did not interfere with the neutralizing capacity of Psidium guajava against the A. actinomycetemcomitans leukotoxin. In addition, it was shown that the O. vulgare EO had an antibacterial effect against A. actinomycetemcomitans on a similar level as some tested antimicrobials. In view of these findings, we suggest that O.vulgare EO may be used as an adjuvant for prevention and treatment of periodontal diseases associated to A. actinomycetemcomitans. In addition, it can be used together with the previously tested leukotoxin neutralizing Psidium guajava.

Whole Genome Sequencing of Aggregatibacter actinomycetemcomitans Cultured from Blood Stream Infections Reveals Three Major Phylogenetic Groups Including a Novel Lineage Expressing Serotype a Membrane O Polysaccharide.

Twenty-nine strains of Aggregatibacter actinomycetemcomitans cultured from blood stream infections in Denmark were characterised. Serotyping was unremarkable, with almost equal proportions of the three major types plus a single serotype e strain. Whole genome sequencing positioned the serotype e strain outside the species boundary; moreover, one of the serotype a strains was unrelated to other strains of the major serotypes and to deposited sequences in the public databases. We identified five additional strains of this type in our collections. The particularity of the group was corroborated by phylogenetic analysis of concatenated core genes present in all strains of the species, and by uneven distribution of accessory genes only present in a subset of strains. Currently, the most accurate depiction of A. actinomycetemcomitans is a division into three lineages that differ in genomic content and competence for transformation. The clinical relevance of the different lineages is not known, and even strains excluded from the species sensu stricto can cause serious human infections. Serotyping is insufficient for characterisation, and serotypes a and e are not confined to specific lineages.

Differential Cell Lysis Among Periodontal Strains of JP2 and Non-JP2 Genotype of Aggregatibacter actinomycetemcomitans Serotype B Is Not Reflected in Dissimilar Expression and Production of Leukotoxin.

Leukotoxic potential of Aggregatibacter actinomycetemcomitans strains has been studied by the use of several methods, and results differ depending on the methods used. The aim of the present study was to perform a comprehensive examination of the leukotoxic potential of a collection of A. actinomycetemcomitans strains by use of three quantitative methods, Western blotting, ELISA, and mRNA expression assay and compare these results with previous data obtained by a cell lysis assay. A higher leukotoxic potential among JP2 genotype strains compared to non-JP2 genotype strains of A. actinomycetemcomitans was found by Western blotting, ELISA and mRNA expression assay. Leukotoxicity as determined by cell lysis assay showed a variation among strains examined, not only depending on being part of JP2 genotype vs. non-JP2 genotype group of A. actinomycetemcomitans. The leukotoxicity of A. actinomycetemcomitans strains as determined by cell lysis assay did not correspond to the leukotoxic potential of A. actinomycetemcomitans strains as determined by three quantitative methods. A comparison of the results obtained by ELISA and mRNA expression assay showed a reasonable correlation between these two methods. It seems important to use more than one method to assess the LtxA-related virulence capacity of A. actinomycetemcomitans in order to obtain comprehensive understanding of the leukotoxic potential of A. actinomycetemcomitans strains.

Comprehensive antimicrobial susceptibility testing of a large collection of clinical strains of Aggregatibacter actinomycetemcomitans does not identify resistance to amoxicillin.

The present study aims to determine the susceptibility of Aggregatibacter actinomycetemcomitans to amoxicillin by investigating a large collection of oral strains of diverse geographical origin. Two hundred and fifty-seven A.actinomycetemcomitans strains were serotyped using a multiplex polymerase chain reaction, and minimal inhibitory concentration (MIC) values of amoxicillin were determined using the agar dilution method (range 0.25-8.0mg/L). The plates were spot-wise inoculated with approximately 104 colony-forming units, incubated in 5% CO2 at 37 C°, and visually inspected after 24 and 48hr. A MIC≤2.00mg/L was categorised as susceptible using EUCAST interpretative criteria for Haemophilus species. Amoxicillin MIC values varied from 0.25mg/L to 2.00mg/L, and all tested strains, including strains previously reported as resistant, were susceptible to amoxicillin. The MIC50 was 1.00mg/L and the MIC90 was 2.00mg/L. Meticulous investigation of strains including isolates previously reported as resistant could not confirm the emergence of resistance to β-lactams in A.actinomycetemcomitans. Based on the present in vitro results, amoxicillin can be considered a key oral antimicrobial agent for treatment of A.actinomycetemcomitans.

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.

Phosphorylcholine is located in Aggregatibacter actinomycetemcomitans fimbrial protein Flp 1

Phosphorylcholine (ChoP) is covalently incorporated into bacterial surface structures, contributing to host mimicry and promoting adhesion to surfaces. Our aims were to determine the frequency of ChoP display among Aggregatibacter actinomycetemcomitans strains, to clarify which surface structures bear ChoP, and whether ChoP-positivity relates to serum killing. The tested oral (N = 67) and blood isolates (N = 27) represented 6 serotypes. Mab TEPC-15 was used for immunoblotting of cell lysates and fractions and for immunofluorescence microscopy of cell surface-bound ChoP. The lysates were denatured with urea for hidden ChoP or treated with proteinase K to test whether it binds to a protein. Three ChoP-positive and two ChoP-negative strains were subjected to serum killing in the presence/absence of CRP and using Ig-depleted serum as complement source. Cell lysates and the first soluble cellular fraction revealed a < 10 kDa band in immunoblots. Among 94 strains, 27 were ChoP positive. No difference was found in the prevalence of ChoP-positive oral (21/67) and blood (6/27) strains. Immunofluorescence microscopy corresponded to the immunoblot results. Proteinase K abolished ChoP reactivity, whereas urea did not change the negative result. The TEPC-15-reactive protein was undetectable in Δflp1 mutant strain. The survival rate of serotype-b strains in serum was 100% irrespective of ChoP, but that of serotype-a was higher in ChoP-positive (85%) than ChoP-negative (71%) strains. The results suggest that a third of rough-colony strains harbor ChoP and that ChoP is attached to fimbrial subunit protein Flp1. It further seems that ChoP-positivity does not enhance but may reduce A. actinomycetemcomitans susceptibility to serum killing.

Determination of MIC of amoxicillin among clinical strains of Aggregatibacter actinomycetemcomitans from various geographic regions endorse the continuous use of this drug for treatment of periodontitis

ABSTRACTAim: The combination of amoxicillin and metronidazole is used in the treatment of Aggregatibacter actinomycetemcomitans (Aa)-associated periodontitis in some patients. Aa is innately susceptible to betalactam agents, but resistance or decreased susceptibility has been reported. Elucidation of the prevalence and mechanisms of resistance to betalactams in Aa is important in order to treat periodontitis patients with the most optimal antibiotic regimen.Method: 259 Aa strains were collected from patients with geographically diverse origin and serotyped with a multiplex PCR. Minimal inhibitory concentration (MIC) values were determined using the agar dilution method, with amoxicillin (range 0.00 mg/L to 8.00 mg/L) incorporated into 5 % blood agar plates with 20 mg/mL NAD. The plates were inoculated with 1 μL bacterial suspensions (104 CFU/ml), incubated in 5 % CO2 at 37 C°, and visually inspected after 24 and 48 hours. A MIC ≥ 4.00 mg/L was categorised as resistant, using EUCAST interpretative criteria for Haemophilus species.Results: None of 259 clinical Aa strains exhibited resistance towards amoxicillin. MIC-values varied from 0.25 mg/L to 2.00 mg/L. There was no clear correlation between MIC-value and serotype.Conclusion: The study showed no contraindications to the continuous use of amoxicillin as a part of the treatment strategy in patients with Aa-associated periodontitis.

Colonization and Persistence of Labeled and "Foreign" Strains of Aggregatibacter actinomycetemcomitans Inoculated into the Mouths of Rhesus Monkeys.

Aggregatibacter actinomycetemcomitans (Aa) is a pathobiont and part of a consortium of bacteria that can lead to periodontitis in humans. Our aim was to develop a model for oral inoculation of labeled Aa into a suitable host in order to study Aa traits and ecological factors that either enhance or repress its persistence. Primate species were screened for Aa to select a host for colonization studies. Macaca mulatta (Rhesus/Rh) was selected. Rh Aa strains were isolated, subjected to sequencing and functional analysis for comparison to human strains. "Best" methods for microbial decontamination prior to inoculation were assessed. Three groups were studied; Group 1 (N=5) was inoculated with Aa Spectinomycin resistant (SpecR) Rh strain 4.35, Group 2 (N=5) inoculated with Aa SpecR human strain IDH 781, and Group 3 (N=5) the un-inoculated control. Repeated feeding with pancakes spiked with SpecRAa followed high dose oral inoculation. Cheek, tongue, and plaque samples collected at baseline 1, 2, 3, and 4 weeks after inoculation were plated on agar; 1) selective for Aa, 2) enriched for total counts, and 3) containing 50 µg/ml of Spec. Aa was identified by colonial morphology and DNA analysis. Rh and human Aa had > 93-98 % genome identity. Rh Aa attached to tissues better than IDH 781 in vitro (p < 0.05). SpecR IDH 781 was not recovered from any tissue at any time; whereas, RhSpecR 4.35 was detected in plaque, but never tongue or cheek, in all monkeys at all times (> 1 × 105 colonies/ml; p < 0.001). In conclusion, the primate model provides a useful platform for studying integration of Aa strains into a reduced but established oral habitat. Primate derived SpecRAa was consistently detected in plaque at all collection periods; however, human derived Aa was never detected. The model demonstrated both microbial as well as tissue specificity.

Formulation and evaluation of antimicrobial activity of Morus alba sol-gel against periodontal pathogens

Background: Periodontitis has a multifactorial etiology, with primary etiologic agents being pathogenic bacteria that reside in the subgingival area. Recent advances in the field of alternative medicine introduced various herbal products for the treatment of periodontitis. Aim: To assess and compare the antimicrobial activity of Morus alba sol-gel with chlorhexidine sol-gel against ATCC standard strains of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia. Materials and Methods: Crude extract of Morus alba leaves was prepared by Soxhlet method by using ethanol as a solvent. Phytochemical screening of the crude extract of M. alba was performed to check the various chemical constituents. M. alba sol-gel and chlorhexidine sol-gel were formulated using Pluronic f127 and Pluronic f108 and compared for their antimicrobial activity. The minimum inhibitory concentration of both the gels was performed using agar well diffusion technique. Results: The minimum inhibitory concentration of M. alba sol-gel and chlorhexidine sol-gel against A. actinomycetemcomitans is 19 and 17 mm, T. forsythia is 12 and 21 mm, and P. gingivalis is 16 and 18 mm, respectively. Conclusion: Both M. alba and chlorhexidine sol-gel exhibited potent antimicrobial activity against periodontal pathogens.

Antibacterial activity of moxifloxacin on bacteria associated with periodontitis within a biofilm

The activity of moxifloxacin was compared with ofloxacin and doxycycline against bacteria associated with periodontitis within a biofilm (single strain and mixed population) in vitro. MICs and minimal bactericidal concentrations (MBCs) of moxifloxacin, ofloxacin and doxycyline were determined against single strains and mixed populations in a planktonic state. Single-species biofilms of two Porphyromonas gingivalis and two Aggregatibacter actinomycetemcomitans strains and a multispecies biofilm consisting of 12 species were formed for 3 days. The minimal biofilm eradication concentrations (MBECs) were determined after exposing the biofilms to the antibacterials (0.002-512 µg ml(-1)) for 18 h, addition of nutrient broth for 3 days and subsequent subcultivation. Photographs were taken using confocal laser-scanning microscopy and scanning electron microscopy. The MICs and MBCs did not differ between ofloxacin and moxifloxacin against A. actinomycetemcomitans, whilst moxifloxacin was more active than the other tested antibacterials against anaerobes and the mixed population. The single-species biofilms were eradicated by moderate concentrations of the antibacterials, and the lowest MBECs were always found for moxifloxacin (2-8 µg ml(-1)). MBECs against the multispecies biofilms were 128, >512 and >512 µg ml(-1) for moxifloxacin, ofloxacin and doxycycline, respectively. In summary, moxifloxacin in a topical formulation may have potential as an adjunct to mechanical removal of the biofilms.

The effect of chlorhexidine mouth wash and visible blue light on Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis of patients with chronic periodontitis ( an in–vitro study)

Aims of the study: to determine the effect of 0.2% chlorhexidine digluconate mouthwash and visible blue light on anaerobic periodontal pathogens namely Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Materials& Methods : Strains of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were isolated from pockets of systemically healthy patients aged between 35-55 years old with pocket depths of 5-6 mm, the bacteria cultured on blood Agar plates containing holes filled with 0.1 ml of 0.2% chlorhexidine, subjected to visible blue light emitted from commercially available light cure devise (LED curing light); that emits blue light (400-500nm) of 1000mw energy at different rates of time exposures, then the inhibition zones of each plate was measured by special ruler after 48hours of anaerobic incubation. Results showed that there was an increase in inhibition zone around the chlorhexidine holes, measured by millimeters as we proceed from zero, 20, 40 and 60 seconds of blue light exposure. Conclusion there is a synergistic effect between visible blue light emitted from the light curing device and 0.2% chlorhexidine digluconate mouth wash against the anaerobic periodontal pathogens.

Antimicrobial Activity of Berberine against Oral Bacteria Related to Endodontic Infections

It has been established that berberine has strong antimicrobial effects. Little is known however regarding the antimicrobial activity of berberine against endodontic pathogenic bacteria or its cytotoxicity in human oral tissue cells. The antibacterial properties of berberine were tested against 5 strains of Enterococcus faecalis and type strains of Aggregatibacter actinomycetemcomitans, Prevotella nigrescens, Prevotella intermedia, and Tannerella forsythia, which are involved in endodontic infections. Antimicrobial activity was evaluated through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) measurements. The viability of normal human gingival fibroblast (NHGF) cells after exposure to berberine was measured using a methyl thiazolyl tetrazolium (MTT) assay. The data showed that berberine has antimicrobial effects against A. actinomycetemcomitans with an MIC and MBC of 12.5 μg/ml and 25 μg/ml, respectively. In the cytotoxicity studies, cell viability was maintained at 66.1% following exposure to 31.3 μg/ml berberine. Overall, these findings suggest that berberine has antimicrobial activity against the tested bacteria. Nevertheless, lower concentrations in combination with other reagents will need to be tested before these in vitro results can be translated to clinical use.

Serotype‐dependent response of human dendritic cells stimulated with Aggregatibacter actinomycetemcomitans

Different serotypes of Aggregatibacter actinomycetemcomitans have been described based on the lipopolysaccharide (LPS)-O-polysaccharide antigenicity. In turn, a distinct effect of A. actinomycetemcomitans serotypes has been described on cell proliferation and pro-inflammatory cytokine production in different human cells. This study was aimed to investigate the differential dendritic cell (DC) response when stimulated with different bacterial strains belonging to the most prevalent serotypes of A. actinomycetemcomitans (a-c). Dendritic cells were obtained from healthy subjects and stimulated with increasing multiplicity of infection (MOI = 10(-1) -10(2)) of A. actinomycetemcomitans, serotypes a-c, or their lipopolysaccharide (10-50 ng/ml). The levels for interferon (IFN)-γ, tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-5, IL-6, IL-10, IL-12 and IL-23 were quantified by real-time RT-PCR and ELISA. Variable DC responses were detected when stimulated with the different strains of A. actinomycetemcomitans. DCs stimulated with A. actinomycetemcomitans strains belonging to the serotype b or their purified LPS expressed higher levels of IL-1β, IL-6, IL-12, IL-23, IFN-γ and TNF-α than DCs stimulated with the other serotypes. Aggregatibacter actinomycetemcomitans strains belonging to the serotype b demonstrated a higher capacity to trigger Th1 and Th17-type cytokine production on DCs. These increased potential is likely explained by a higher immunogenicity of their LPS.