Synergistic antibacterial activity of herbal extracts with antibiotics on bacteria responsible for periodontitis.

INTRODUCTION: Development of bacterial resistance and antimicrobial side-effect has shifted the focus of research toward Ethnopharmacology. A biologically active compound derived from the plants may increase the effectiveness of antibiotic when used in combination. The present study aims to determine the synergistic antibacterial effect of ethanolic extracts of Punica granatum (pericarp), Commiphora molmol, Azadirachta indica (bark) in combination with amoxicillin, metronidazole, tetracycline, and azithromycin on periodontopathic bacteria: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola and Aggregatibacter actinomycetemcomitans. METHODOLOGY: Periodontopathic bacterial strains were isolated from the plaque sample that was collected from periodontitis patients and grown under favorable conditions. Susceptibility of bacteria to the antibiotics and extracts was determined by disc diffusion method by measuring the diameter of the inhibition zones. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant extracts were evaluated against each bacterium. Synergistic effect of plant extract in combination with antibiotics was tested against each bacterium by measuring the diameter of zone of inhibition (ZOI). RESULTS: Findings revealed that all plant extracts exhibited an inhibitory effects on the proliferation and growth of periodontopathic bacteria. The maximum antibacterial effect was exhibited by C. molmol on P. gingivalis (ZOI = 20 ± 0.55 mm, MIC = 0.53 ± 0.24 mg/mL and MBC = 5.21 ± 1.81 mg/mL) (p < 0.05), meanwhile, no antibacterial activity was exhibited by P. granatum on T. forsythia. Synergistic antibacterial effect was recorded when plant extracts were used in combination with antibiotics. The best synergism was exhibited by P. granatum with amoxicillin against A. actinomycetemcomitans (24 ± 1.00 mm) (p < 0.05). CONCLUSIONS: The synergistic test showed significant antibacterial activity when plant extracts were combined with antibiotics against all the experimented bacteria.

Effect of cranberry juice deacidification on its antibacterial activity against periodontal pathogens and its anti-inflammatory properties in an oral epithelial cell model.

Cranberries are widely recognized as a functional food that can promote oral health. However, the high concentration of organic acids in cranberry juice can cause tooth enamel erosion. Electrodialysis with bipolar membrane (EDBM) is a process used for the deacidification of cranberry juice. The present study investigated whether the removal of organic acids (0%, 19%, 42%, 60%, and 79%) from cranberry juice by EDBM affects its antibacterial activity against major periodontopathogens as well as its anti-inflammatory properties in an oral epithelial cell model. A deacidification rate ≥60% attenuated the bactericidal effect against planktonic and biofilm-embedded Aggregatibacter actinomycetemcomitans but had no impact on Porphyromonas gingivalis and Fusobacterium nucleatum. Cranberry juice increased the adherence of A. actinomycetemcomitans and P. gingivalis to oral epithelial cells, but reduced the adherence of F. nucleatum by half regardless of the deacidification rate. F. nucleatum produced more hydrogen sulfide when it was exposed to deacidified cranberry juice with a deacidification rate ≥42% compared to the raw beverage. Interestingly, the removal of organic acids from cranberry juice lowered the cytotoxicity of the beverage for oral epithelial cells. Deacidification attenuated the anti-inflammatory effect of cranberry juice in an in vitro oral epithelial cell model. The secretion of IL-6 by lipopolysaccharide (LPS)-stimulated oral epithelial cells exposed to cranberry juice increased proportionally with the deacidification rate. No such effect was observed with respect to the production of IL-8. This study provided evidence that organic acids, just like phenolic compounds, might contribute to the health benefits of cranberry juice against periodontitis.

Epigallocatechin gallate alters leukotoxin secretion and Aggregatibacter actinomycetemcomitans virulence.

OBJECTIVES: We and others have previously shown that epigallocatechin gallate (EGCg) inhibits the activity of an important virulence factor, leukotoxin (LtxA), produced by the oral bacterium Aggregatibacter actinomycetemcomitans, suggesting the potential use of this molecule as an anti-virulence strategy to treat periodontal infections. Here, we sought to better understand the effects of EGCg on toxin secretion and A. actinomycetemcomitans pathogenicity in a co-culture model. METHODS: We used a quantitative immunoblot assay to determine the concentrations of LtxA in the bacterial supernatant and on the bacterial cell surface. Using a co-culture model, consisting of A. actinomycetemcomitans and THP-1 cells, we studied the impact of EGCg-mediated changes in LtxA secretion on the toxicity of A. actinomycetemcomitans. KEY FINDINGS: EGCg increased production of LtxA and changed the localization of secreted LtxA from the supernatant to the surface of the bacterial cells. In the co-culture model, a single low dose of EGCg did not protect host THP-1 cells from A. actinomycetemcomitans-mediated cytotoxicity, but a multiple dosing strategy had improved effects. CONCLUSIONS: Together, these results demonstrate that EGCg has important, but complicated, effects on toxin secretion and activity; new dosing strategies and comprehensive model systems may be required to properly develop these anti-virulence activities.

Development of an enzyme-enhancer system to improve laccase biological activities.

The present investigation reports an in-vitro study using combination of laccase and an enhancer capable of inhibiting the growth of pathogenic microorganisms, preventing biofilm formation, and whitening teeth. Laccase-cinnamic acid system remarkably inhibited the growth of Aggregatibacter actinomycetemcomitans, Candida albicans, S. aureus, and Streptococcus mutans whilst showed no significant effects on Gram-negative bacteria. Data presented that cinnamic acid (10 mM) with laccase (0.125 U ml-1) led to a maximum decrease of about 90%, in S. mutans biofilm formation. The confocal laser scanning microscopy showed considerable detachment of S. mutans cells from glass substratum. The combined laccase-cinnamic acid system could remove teeth discoloration caused by coffee. SEM of the teeth surface exhibited no damages such as surface cracking or fracture. Liquid chromatography-tandem mass spectrometry (LC-MS) and cyclic voltammetry (CV) studies showed that laccase can catalyze the one-electron oxidation of cinnamic acid to the respective radical. This radical can then undergo several fates, including recombination with another radical to form a dimeric species, dismutation of the radical back to cinnamic acid or decarboxylation to give various reduced oxygen species. Therefore, the redox potential values of phenolic monomers/oligomers are related with their biological activities.

Maillard reaction products inhibit the periodontal pathogen Aggregatibacter actinomycetemcomitans by chelating iron.

OBJECTIVE: To determine the mechanism of growth inhibition of Aggregatibacter actinomycetemcomitans by Maillard reaction products (MRP). DESIGN: Growth and cell viabilities in the presence or absence of MRP were measured for both the rough and smooth variants of the bacteria. Effects of addition of ferrous and ferric ions on the inhibition of the bacteria by MRP were determined. RESULTS: MRPs decreased the extent of complex formation of Chrome Azurol S with iron suggesting that MRPs can chelate iron effectively. The chelation causes growth inhibition of both the rough and smooth strains. At low concentrations of the inhibitor, lag time was extended by approximately 12 h while at high concentrations, cells were killed, decreasing cell viability by up to 8 orders of magnitude. Growth of both the rough and smooth strains could be restored to original level by addition of iron. For the rough strain, both ferrous and ferric ions could relieve the inhibition by MRP while for the smooth strain only ferrous ion was effective. CONCLUSION: MRPs inhibit the growth of A. actinomycetemcomitans by chelating iron and the inhibition can be relieved by addition of iron.

Long-term antibacterial activity of a composite coating on titanium for dental implant application.

Dental implants are the most innovative and superior treatment modality for tooth replacement. However, titanium implants still suffer from insufficient antibacterial capability and peri-implant diseases remain one of the most common and intractable complications. To prevent peri-implant diseases, a composite coating containing a new antibacterial agent, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone (BBF) was fabricated on titanium. This study was designed to investigate the antibacterial activity of the composite coating against two common peri-implant pathogens (Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans). The morphology of the composite coating showed that BBF-loaded poly(L-lactic acid) nanospheres were well-distributed in the pores of the microarc oxidation coating, and cross-linked with each other and the wall pores by gelatin. A release study indicated that the antibacterial coating could sustain the release of BBF for 60 d, with a slight initial burst release occurring during the first 4 h. The antibacterial rate of the composite coating for adhering bacteria was the highest (over 97%) after 1 d and over 90% throughout a 30-day incubation period. The total fluorescence intensity of the composite coating was the lowest, and the vast majority of the fluorescence was red (dead bacteria). Moreover, real-time polymerase chain reaction analysis confirmed that the relative gene expression of the adherent bacteria on the composite coating was down-regulated. It was therefore concluded that the composite coating fabricated on titanium, which showed excellent and relatively long-term antibacterial activity against Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, is a potential and promising strategy to be applied on dental implants for the prevention of peri-implant diseases.

Antibacterial activity of nitric oxide-releasing carboxymethylcellulose against periodontal pathogens.

The prevalence of periodontal disease poses a significant global health burden. Treatments for these diseases, primarily focused on removal and eradication of dental plaque biofilms, are challenging due to limited access to periodontal pockets where these oral pathogens reside. Herein, we report on the development and characterization of nitric oxide (NO)-releasing carboxymethylcellulose (CMC) derivatives and evaluate their in vitro bactericidal efficacy against planktonic Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, two prominent periodontopathogens. Bactericidal exposure assays revealed that three of the synthesized NO-releasing polymers were capable of reducing bacterial viability of both species by 99.9% in 2 hr at concentrations of 4 mg ml-1 or lower, reflecting NO's potent and rapid bactericidal action. The NO-releasing CMCs elicited minimal toxicity to human gingival fibroblasts at their bactericidal concentrations following 24-hr exposure.

Weissella cibaria CMU exerts an anti­inflammatory effect by inhibiting Aggregatibacter actinomycetemcomitans­induced NF­κB activation in macrophages.

Periodontitis is a chronic inflammatory disease caused by various periodontal pathogens. Weissella cibaria CMU (oraCMU) is a probiotic that promotes oral health. However, its anti­inflammatory effects against periodontal pathogens have not yet been investigated. The present study evaluated the anti­inflammatory effects of live oraCMU against stimulation with the formalin­inactivated periodontal pathogen Aggregatibacter actinomycetemcomitans in RAW 264.7 macrophages. Cell viability was analyzed by the MTS assay in a dose­dependent manner (at multiplicities of infection of 0.1, 1, 10, 100 and 1,000). Nitric oxide (NO) was monitored using the Griess test. The mRNA expression of proinflammatory cytokines such as interleukin (IL)1ß and IL6 was assessed by reverse transcription­quantitative PCR. Western blotting was used to examine the effects of oraCMU on the phosphorylation of NF­κB inhibitor α (IκBα) and IκBα kinase (IKK), the nuclear translocation of the NF­κB subunit p65 and the expression of inducible NO synthase (iNOS). Live oraCMU had no cytotoxic effects on RAW 264.7 macrophages. In A. actinomycetemcomitans­stimulated RAW 264.7 macrophages, oraCMU reduced NO production by suppressing iNOS expression and downregulating the mRNA expression of proinflammatory cytokines in a dose­dependent manner. IKK phosphorylation and IκBα degradation were dose­dependently inhibited by oraCMU and the nuclear translocation of p65 via the canonical NF­κB pathway was simultaneously reduced. The results indicated that oraCMU possessed anti­inflammatory activity associated with the inhibition of NF­κB signal activation in response to periodontal pathogens. This suggests that oraCMU is a beneficial anti­inflammatory probiotic that can aid in the maintenance of oral health.

An Antibacterial Strategy of Mg-Cu Bone Grafting in Infection-Mediated Periodontics.

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.

Bactericidal activity and recovery effect of hydroxyl radicals generated by ultraviolet irradiation and silver ion application on an infected titanium surface.

This study investigated the bactericidal effect, the underlying mechanisms of treatment, and recovery of biocompatibility of the infected titanium surface using a combination treatment of silver ion application and ultraviolet-A (UV-A) light irradiation. Streptococcus mutans and Aggregatibacter actinomycetemcomitans were used in suspension and as a biofilm on a titanium surface to test for the bactericidal effect. The bactericidal effect of the combination treatment was significantly higher than that of silver ion application or UV-A light irradiation alone. The bactericidal effect of the combination treatment was attributable to hydroxyl radicals, which generated from the bacterial cell wall and whose yield increased with the silver concentration. To assess the biocompatibility, proliferation and calcification of MC3T3E1 cells were evaluated on the treated titanium surface. The treated titanium screws were implanted into rat tibias and the removal torques were measured 28 days post-surgery. The titanium surface that underwent the combination treatment exhibited recovery of biocompatibility by allowing cellular proliferation or calcification at levels observed in the non-infected titanium surfaces. The removal torque 28 days after surgery was also comparable to the control values. This approach is a novel treatment option for peri-implantitis.

High-Potential surface on zirconia ceramics for bacteriostasis and biocompatibility.

Bacteria easily adhere, colonize, and form biofilm on oral implants subsequently causing periimplantation periarthritis and mechanical loosening. Previous studies show that a high potential surface on polymeric implants can achieve surface bacteriostasis without side effects. In this study, a high surface potential is introduced to zirconia ceramics to mitigate bacterial infection. Carbon and nitrogen plasma immersion ion implantation (C-PIII and N-PIII) are conducted on zirconia ceramic samples sequentially to elevate the surface potential. The surface with a high potential but without ion leaching exhibits excellent antibacterial effects against oral bacteria and little bacterial resistance is triggered. The surface also has high strength and excellent biocompatibility. The nitrogen-containing inorganic structure with high potential can actualize bacteriostasis and biocompatibility on zirconia ceramics simultaneously and this new strategy can enhance the antibacterial ability of oral implants.

Electrospun PLA Fibers Containing Metronidazole for Periodontal Disease.

PURPOSE: Electrospun PLA fiber devices were investigated in the form of fiber mats and disks. Metronidazole was used as an active agent; its concentration was 12.2 and 25.7 wt% in the devices. METHODS: The structure was studied by X-ray diffraction and scanning electron microscopy, drug release by dissolution measurements, while the antimicrobial efficiency was tested on five bacterial strains. RESULTS: The XRD study showed that the polymer was partially crystalline in both devices, but a part of metronidazole precipitated and was in the form of crystals among and within the fibers. Liquid penetration and dissolution were different in the two devices, they were faster in disks and slower in fiber mats, due to the morphology of the device and the action of capillary forces. Disks released the drug much faster than fiber mats. Although the release study indicated fast drug dissolution, the concentration achieved a plateau value in 24 hrs for the disks; the inhibition effect lasted much longer, 13 days for bacteria sensitive to metronidazole. The longer inhibition period could be explained by the slower diffusion of metronidazole located inside the fibers of the device. CONCLUSION: The results suggest that the devices may be effective in the treatment of periodontitis.

Antibacterial activity of viable and heat-killed probiotic strains against oral pathogens.

Probiotics can stabilize gut flora, regulate intestinal immunity and protect the host from enteric diseases; however, their roles in oral health have received little attention compared to their roles in gut health. Nowadays, the prevalence of sugar-sweetened foods and abuse of antibiotics contribute towards dysbiosis of oral microbiota and drug resistance development in oral pathogens, resulting in various intractable oral diseases. We screened the antibacterial activities of viable and heat-killed probiotic strains against the oral pathogens Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. The probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 displayed strong antipathogenic activities, whereas heat-killed AP-32, CT-53 and ET-66 displayed high levels of pathogen inhibition. The antibacterial activities of these probiotics were not associated with their H2 O2 production; L. acidophilus TYCA02 produced high levels of H2 O2 but merely exhibited moderate antibacterial activities. Oral tablets containing probiotics showed positive inhibitory effects against oral pathogens, particularly those containing viable probiotics. Our results indicate that probiotics prevent the growth of oral pathogens and improve oral health, providing insights into the antipathogenic efficacy of different probiotic species and their potential role in functional foods that improve oral health. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study provides insights into the antipathogenic efficacy of different probiotic species and their potential roles in developing functional foods to improve oral health. We showed that the probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 have great potential for use in the development of functional foods to improve oral health. Since active probiotics may provide strong and long-term protection, the development of functional food products should favour the use of viable bacteria.

Biofunctionalized zinc peroxide nanoparticles inhibit peri-implantitis associated anaerobes and Aggregatibacter actinomycetemcomitans pH-dependent.

For dental implants the accumulation of anaerobic bacteria is a main reason for peri-implant inflammation, which untreated can lead to implant loss. Oxygen releasing substances may act as antibacterial agents. In this study glucose-1-phosphate (Glc-1P) biofunctionalized zinc peroxide (ZnO2) nanoparticles of four different synthesis ratio (1-10:1) and sizes (4-5 nm) were tested against the anaerobes Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia, as well as against Aggregatibacter actinomycetemcomitans, Enterococcus faecalis, Staphylococcus aureus, Lactobacillus paracasei, and the yeast Candida albicans. Nanoparticles stabilized with o-phosphorylethanolamine, bis[2-(methacryloyloxy)ethyl] phosphate, or dioctyl sulfosuccinate instead of glucose were used as controls. For every combination of test strain and nanoparticle both, the minimal inhibitory (MIC) and minimal microbicidal concentration (MBC or MFC) were determined under different pH conditions in microtiter plates. Furthermore, transmission electron (TEM) and fluorescence microscopy after live-dead-staining was performed on selected combinations of pathogen and nanoparticle in order to visualize the interactions. The ZnO2/Glc-1P nanoparticles had an inhibitory effect on gram-negative anaerobes and on A. actinomycetemcomitans with a pH-dependent MIC ≥25 µg/ml and MBC ≥50 µg/ml, while the gram-positive species tested and C. albicans were not inhibited. In TEM images, attachment of nanoparticle-chains to the bacterial outer membrane and subsequent penetration was found together with an intracellular oxygen release. For nanoparticles with other stabilizers than glucose an invasion was only seen in elongated, dividing cells, possibly because of the more porous cell wall in the parting layer. Decorating ZnO2 by glucose-1-phosphate is a Trojan horse approach to permit their uptake in gram-negative oxygen-sensitive bacterial cells.

Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Abstract Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Photoexcitation triggering via semiconductor Graphene Quantum Dots by photochemical doping with Curcumin versus perio-pathogens mixed biofilms.

BACKGROUND: Recently, antimicrobial photodynamic therapy (aPDT) as an alternative treatment modality has been used adjunctively in the treatment of periodontitis and peri-implantitis. Photosensitizing agents in the form of nanoparticles have been designed for improving the efficiency of aPTD. Graphene quantum dots are a special type of nanocrystals that can promote aPDT when coupled with curcumin (Cur). The main objective of the present study was to investigate the effects of photoexcited GQD-Cur on the metabolic activity of perio-pathogen mixed biofilms. MATERIALS AND METHODS: GQD-Cur was synthesized and characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible spectrometry (UV-Vis), and X-ray diffraction (XRD). The cell cytotoxicity effect of GQD-Cur was evaluated on primary human gingival fibroblast (HuGu) cells. Perio-pathogen mixed biofilms including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia photosensitized with GQD doped with Cur were irradiated with a blue LED at a wavelength of 435 ± 20 nm for 1 min, and then bacterial viability measurements were performed. The antimicrobial susceptibility profile, biofilm formation ability, amount of reactive oxygen species (ROS) released, and variations of gene expressions involved in biofilm formation were assessed. RESULTS: The SEM, DLS, FTIR, UV-Vis spectrometry, and XRD pattern confirmed that GQD-Cur was synthesized successfully. According to the results, GQD-Cur exhibited no cytotoxicity against HuGu cells. Photoexcited GQD-Cur resulted in a significant reduction in cell viability (93%) and biofilm formation capacity (76%) of peri-pathogens compared to the control group (P < 0.05). According to the results, a significant concentration-dependent increase in the ROS generation was observed in perio-pathogens mixed cells treated with different doses of GQD-Cur-aPDT. Moreover, rcpA, fimA, and inpA gene expression profiles were downregulated by 8.1-, 9.6-, and 11.8-folds, respectively. CONCLUSIONS: Based on the results, photoexcited GQD-Cur have a high potency of perio-pathogens suppression in planktonic and biofilm forms and downregulation of the biofilm genes expression pattern was exploited as a nanoscale-based platform for periodontitis.

Mixed Actinomyces israelii and Aggregatibacter actinomycetemcomitans infection causing empyema necessitatis and multiple skin abscesses in an immunocompetent patient.

A 45-year-old- man presented with left chest wall pain, swelling and cough. Over a 2-month period he developed abscesses in the right foot, right anterior thigh, left buttock and left chest. Incision and drainage of the soft tissue abscesses and video-assisted thoracoscopic surgery to drain the loculated empyema contiguous with the chest wall abscess were performed as surgical management. Gram stain showed beaded Gram-positive rods and the culture initially grew Aggregatibacter actinomycetemcomitans and Eikenella corrodens Pathological evaluation of the pleura showed sulfur granules and organisms consistent with Actinomyces spp. on Gomori methenamine silver stain; Actinomyces israelii was recovered in culture with extended incubation. The patient was treated for 3 weeks with ceftriaxone and oral metronidazole, followed by oral amoxicillin. Culture of A. actinomycetemcomitans with other findings consistent with actinomycosis warrants 6-12 months of antibiotic therapy.

Efficacy of antimicrobial photodynamic therapy for elimination of Aggregatibacter actinomycetemcomitans biofilm on Laser-Lok titanium discs.

BACKGROUND: Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs. MATERIALS AND METHODS: Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 µg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test. RESULTS: Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05). CONCLUSION: Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs.

Development of antiseptic adaptation and cross-adapatation in selected oral pathogens in vitro.

There is evidence that pathogenic bacteria can adapt to antiseptics upon repeated exposure. More alarming is the concomitant increase in antibiotic resistance that has been described for some pathogens. Unfortunately, effects of adaptation and cross-adaptation are hardly known for oral pathogens, which are very frequently exposed to antiseptics. Therefore, this study aimed to determine the in vitro increase in minimum inhibitory concentrations (MICs) in oral pathogens after repeated exposure to chlorhexidine or cetylpyridinium chloride, to examine if (cross-)adaptation to antiseptics/antibiotics occurs, if (cross-)adaptation is reversible and what the potential underlying mechanisms are. When the pathogens were exposed to antiseptics, their MICs significantly increased. This increase was in general at least partially conserved after regrowth without antiseptics. Some of the adapted species also showed cross-adaptation, as shown by increased MICs of antibiotics and the other antiseptic. In most antiseptic-adapted bacteria, cell-surface hydrophobicity was increased and mass-spectrometry analysis revealed changes in expression of proteins involved in a wide range of functional domains. These in vitro data shows the adaptation and cross-adaptation of oral pathogens to antiseptics and antibiotics. This was related to changes in cell surface hydrophobicity and in expression of proteins involved in membrane transport, virulence, oxidative stress protection and metabolism.

Antimicrobial activity of red wine and oenological extracts against periodontal pathogens in a validated oral biofilm model.

BACKGROUND: Previous research findings support an antimicrobial effect of polyphenols against a variety of pathogens, but there is no evidence of this effect against periodontal pathogens in complex biofilms. The purpose of this study was to evaluate the antimicrobial activity of red wine and oenological extracts, rich in polyphenols, against the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and total bacteria growing in an in vitro oral biofilm static model. METHODS: A previously validated biofilm model, including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, F. nucleatum, P. gingivalis and A. actinomycetemcomitans was developed on sterile hydroxyapatite discs. Red wine (and dealcoholized wine), and two polyphenols-rich extracts (from wine and grape seeds) were applied to 72 h biofilms by dipping the discs during 1 and 5 min in the wine solutions and during 30 s and 1 min in the oenological extracts. Resulting biofilms were analyzed by confocal laser scanning microscopy and viable bacteria (colony forming units/mL) were measured by quantitative polymerase chain reaction combined with propidium monoazide. A generalized linear model was constructed to determine the effect of the tested products on the viable bacterial counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, as well on the total number of viable bacteria. RESULTS: The results showed that red wine and dealcoholized red wine caused reduction in viability of total bacteria within the biofilm, with statistically significant reductions in the number of viable P. gingivalis after 1 min (p = 0.008) and in A. actinomycetemcomitans after 5 min of exposure (p = 0.011) with red wine. No evidence of relevant antibacterial effect was observed with the oenological extracts, with statistically significant reductions of F. nucleatum after 30 s of exposure to both oenological extracts (p = 0.001). CONCLUSIONS: Although moderate, the antimicrobial impact observed in the total bacterial counts and counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, encourage further investigations on the potential use of these natural products in the prevention and treatment of periodontal diseases.