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ACS Sensors Jun 2020Biofilms can cause many bacterial diseases, such as dental disease. An detection of biofilms may help to screen antibiofilm drugs. An impedance measurement based on an...
Biofilms can cause many bacterial diseases, such as dental disease. An detection of biofilms may help to screen antibiofilm drugs. An impedance measurement based on an Au electrode has been successfully used for real-time monitoring of animal and human cell growth. However, microbial growth on the Au electrode produced a poor signal because of the small size of microbial cells. We have recently demonstrated that graphene derivatives can be produced on a carbon electrode through facile electrochemical activation, thus forming a reduced graphene oxide-carbon electrode (rGO-CE). Based on this fact, we hypothesized that an formed rugose graphene layer of rGO-CE may provide a large surface area for the growth of microbial biofilms and can therefore produce a strong impedance signal in response to a change in the biomass. In this study, three oral bacteria, (), (), and (), were cultured on the surfaces of rGO-CE. As a result, the impedance response signal of the rGO-CE for the growth of and was found to be 3.3 times and 6.0 times stronger than that of the Au electrode at 1.17 and 54.7 kHz, respectively. In particular, the poorly adhering strain of also produced a detectable signal on the graphene electrode but not on the Au electrode at 1.17 kHz. Furthermore, destructions of the biofilms grown on the rGO-CE by cetylpyridinium chloride were successfully monitored by impedance changes. Overall, it is promising to develop a graphene-based impedance biosensor platform for biofilm study and antibiofilm drug screening.
Topics: Animals; Biofilms; Biosensing Techniques; Dielectric Spectroscopy; Electrodes; Graphite; Humans
PubMed: 32397709
DOI: 10.1021/acssensors.0c00570 -
Scientific Reports Apr 2020Bacterial extracellular polymeric substances (EPSs) present diverse properties of biotechnological interest, such as surface modification, metal adsorption and...
Bacterial extracellular polymeric substances (EPSs) present diverse properties of biotechnological interest, such as surface modification, metal adsorption and hydrophobic substances solubilization through surface tension reduction. Thus, there is a growing demand for new producing strains and structurally variable biomolecules with different properties. One approach for scanning this biodiversity consists of exploring environments under selective pressures. The aim of this study was to evaluate the composition of culturable heterotrophic bacterial communities from five different sites from a copper mine in the Amazon biome by an enrichment technique to obtain metal resistant bacteria (lead, arsenic, cadmium, copper and zinc) capable of producing EPSs. The bacterial densities at the sites varied from 2.42 × 10 to 1.34 × 10 NMP mL and the 77 bacterial isolates obtained were classified in four divisions, β-Proteobacteria (16.88%), γ-Proteobacteria (7.29%), Firmicutes (61%) and Actinobacteria (12.98%). Bacillus, Alcaligenes, and Lysinibacillus were the most dominant among the 16 observed genera, but the relative frequency of each varied according to the sample and the metal used in the enrichment culture. 58% of the bacterial strains (45) could produce EPSs. From these, 33 strains showed emulsifying activity (E), and 9 of them reached values higher than 49%. Only Actinomyces viscosus E3.Pb5 and Bacillus subtilis group E3.As2 reduced the medium surface tension to values lower than 35 mN m. It was possible to confirm the high presence of bacteria capable of producing EPSs with tensoactive properties in Amazon copper mines and the evolutionary pressure exerted by the heavy metals during enrichment. These molecules can be tested as an alternative for use in processes that involve the removal of metals, such as the bioremediation of contaminated environments.
Topics: Arsenic; Bacteria; Biodegradation, Environmental; Brazil; Cadmium; Copper; Environmental Pollutants; Environmental Pollution; Extracellular Polymeric Substance Matrix; Heterotrophic Processes; Microbiota; Mining; RNA, Ribosomal, 16S; Soil Microbiology; Zinc
PubMed: 32277075
DOI: 10.1038/s41598-020-62780-8 -
Minerva Stomatologica Feb 2020The use of lasers at different wavelengths has been proposed in combination with conventional non-surgical periodontal treatment in order to improve the clinical outcome...
BACKGROUND
The use of lasers at different wavelengths has been proposed in combination with conventional non-surgical periodontal treatment in order to improve the clinical outcome of periodontal disease. However, the clinical use of laser photonic energy is still the subject of research and debate because the antibacterial activity of the laser is dependent upon method, laser parameters, quantity of bacteria, species selected and photosensitizers used.
METHODS
We evaluated the in-vitro bactericidal activity of 810 nm diode-laser irradiation in simultaneous photoablative and photodynamic mode against the major pathogenic bacterial organisms associated with periodontal inflammation and disease. We used indocyanine green as photosensitizer and the high-energy density of 161.7 J/cm2 or 215.0 J/cm2 for the photoablative-photodynamic irradiation.
RESULTS
The bacteria were drastically affected by the 215.0 J/cm2 irradiation in the presence of indocyanine green. In fact, the number of Porphyromonas gingivalis and Prevotella intermedia was reduced by 99.9% (P<0.001), while the number of Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Actinomyces viscosus decremented by 83.3% (P<0.01), 86.8% (P<0.05), 75% (P<0.01) and 78.7% (P<0.001), respectively. P. gingivalis and P. intermedia were the only bacteria that were sensitive to the treatment with indocyanine green dye and 161.7 J/cm2 of laser irradiation (P<0.001).
CONCLUSIONS
Our preliminary in-vitro data suggest that simultaneous photoablative-photodynamic irradiation could be a promising therapy against a wide range of bacteria involved in periodontal disease. We believe that further additional in-vivo investigation is necessary, to enable a more complete picture of effectiveness within a clinical setting to be established. In addition, the use of a simultaneous photoablative-photodynamic therapy is suggested to reduce treatment time, without compromising the efficacy against the periodontal pathogens.
Topics: Aggregatibacter actinomycetemcomitans; Laser Therapy; Lasers, Semiconductor; Photochemotherapy; Photosensitizing Agents
PubMed: 32214064
DOI: 10.23736/S0026-4970.19.04233-X -
Journal of Oral and Maxillofacial... 2019The Ayurvedic system of medicine is popular in India and has gone through various change and remains as the mainstay of medical relief to a large population. Dental...
INTRODUCTION
The Ayurvedic system of medicine is popular in India and has gone through various change and remains as the mainstay of medical relief to a large population. Dental caries is the one of the major issue in the recent time, and there is no definite caries prevention method so far apart from Topical fluoride application, regular oral hygiene measures, pit and fissure sealants and diet measure. In spite of the above mentioned preventive measures the people are still prone to dental caries. In order to find a better solution the present study evaluates the antimicrobial properties widely available and cost effective herbal extracts of Solanum xanthocarpum and Pistacia lentiscus extract on cariogenic oral microbial flora.
AIM
To Evaluate the Antimicrobial properties of Solanum xanthocarpum and Pistacia lentiscus extracts on cariogenic oral microbial flora.
METHODOLOGY
The antimicrobial properties of Solanum xanthocarpum and Pistacia lentiscus extracts on cariogenic oral microbial flora (streptococcus mutans, lactobacillus, actinomyces viscosus) by different culture techniques to estimate the zone of inhibition (well diffusion method) and minimum inhibitory concentration (tube dilution method).
RESULTS
The antimicrobial efficacy of Solanum xanthocarpum and Pistacia lentiscus on test bacteria were analysed using kurskal wallis test and values of 0.003 and 0.002 were obtained respectively, since the values were less than 0.005, indicating that both herbal products possess statistically significant antimicrobial properties.
CONCLUSION
The antimicrobial effects of the herbal extracts were almost on par with commercially available allopathic agents like chlorhexidine on oral cariogenic microbes. The efficacy should be further validated in a large scale studies and can be utilized for caries prevention in the form of mouth rinses, dentifrices and topical application in the future.
PubMed: 31942118
DOI: 10.4103/jomfp.JOMFP_30_19 -
Heliyon Dec 2019Dental caries is a multi-factorial oral disease, requiring a susceptible host, cariogenic microorganisms and suitable substrate. Caries is extended worldwide in spite of...
PURPOSE
Dental caries is a multi-factorial oral disease, requiring a susceptible host, cariogenic microorganisms and suitable substrate. Caries is extended worldwide in spite of the availability of countless prophylactic means, including fluoride toothpaste and dental sealers. Many efforts have been made to achieve isolation of pure natural products for medicinal use. Flavonoids are bioactive polyphenol compounds possessing multidimensional effects such as antibacterial action.
METHODS
The present study targeted the characterization of antibacterial and antifungal activity of various flavonoids (apigenin, catechin, luteolin, morin, myricetin, naringin, quercetin and rutin). Nine strains present in dental plaque were used: and as well as fungal strain.
RESULTS
Results revealed that luteolin, morin, naringin, quercetin and rutin effectively inhibited bacterial and fungal growth. However, morin was the most effective flavonoid.
CONCLUSION
It might then be concluded that flavonoids show bacteriostatic effect on all of tested bacteria and fungus.
PubMed: 31886429
DOI: 10.1016/j.heliyon.2019.e03013 -
Nan Fang Yi Ke Da Xue Xue Bao = Journal... Jul 2019To construct antimicrobial peptides with potent antimicrobial activity, low cytotoxicity and efficient killing rate of for prevention and treatment of dental caries.
OBJECTIVE
To construct antimicrobial peptides with potent antimicrobial activity, low cytotoxicity and efficient killing rate of for prevention and treatment of dental caries.
METHODS
We exploited the existing design strategies to modify reutericin 6 or gassericin A produced by species in the oral cavity based on their cationicity, amphipathicity and -helical structure. We examined their antimicrobial activities using bacterial susceptibility assay, their cytotoxicity through cytotoxicity assay and their killing rate of with time-kill assay. We further evaluated the candidate derivatives for their killing rate against , their antimicrobial activity against different oral pathogens and the development of drug resistance.
RESULTS
We constructed 6 AT-1 derivatives, among which AT-7 showed an MIC of 3.3 μmol/L against , and with a killing rate of 88.7% against within 5 min. We did not obtain strains of resistant to AT- 7 after induction for 10 passages.
CONCLUSIONS
Hydrophobicity and imperfect amphipathic structure are two key parameters that define the antimicrobial potency of the antimicrobial peptides. The imperfectly amphipathic peptide AT-7 shows the potential for clinical application in dental caries treatment.
Topics: Anti-Infective Agents; Dental Caries; Humans; Microbial Sensitivity Tests; Peptides; Streptococcus mutans
PubMed: 31340916
DOI: 10.12122/j.issn.1673-4254.2019.07.12 -
Molecules (Basel, Switzerland) Jun 2019Synthesis of 1,2,3-triazole-substituted coumarins and also 1,2,3-triazolyl or 1,2,3-triazolylalk-1-inyl-linked coumarin-2,3-furocoumarin hybrids was performed by...
Synthesis of 1,2,3-triazole-substituted coumarins and also 1,2,3-triazolyl or 1,2,3-triazolylalk-1-inyl-linked coumarin-2,3-furocoumarin hybrids was performed by employing the cross-coupling and copper catalyzed azide-alkyne cycloaddition reaction approaches. The synthesized compounds were evaluated for their in vitro antibacterial activity against , , and bacterial strains. Coumarin-benzoic acid hybrids , and 3-((4-acetylamino-3-(methoxycarbonyl)phenyl)ethynyl)coumarin () showed promising activity against . strains, and the 1,2,3-triazolyloct-1-inyl linked coumarin-2,3-furocoumarin hybrid was endowed with high selectivity against and species. The in vitro antibacterial activity of , , and can potentially be compared with that of a number of modern antibiotic drugs used in the clinic, suggesting promising prospects for further research. A detailed study of the molecular interactions with the targeted protein MurB was performed using docking simulations and the obtained results are quite promising.
Topics: Anti-Bacterial Agents; Bacteria; Drug Design; Furocoumarins; Microbial Sensitivity Tests; Molecular Docking Simulation; Thermodynamics; Triazoles
PubMed: 31195697
DOI: 10.3390/molecules24112126 -
Zeitschrift Fur Gastroenterologie May 2019We report on a 40-year-old patient who presented with fever, right upper abdominal pain, right-sided chest pain and acute dyspnea. Imaging revealed several liver...
We report on a 40-year-old patient who presented with fever, right upper abdominal pain, right-sided chest pain and acute dyspnea. Imaging revealed several liver abscesses, as well as extensive right pleural empyema. Sixteen weeks previously, the patient underwent tooth extraction of the third molars (18, 28, 38, 48) and a first molar (46), and systematic closed periodontitis treatment. Four different species of the physiological microbiota of the oral cavity were detected in the pleura or liver abscess punctate (Streptococcus anginosus, Streptococcus constellatus, Actinomyces odontolyticus, Prevotella denticola). An underlying immune defect was ruled out. Ultrasound-guided drainage of liver abscesses and surgical treatment of pleural empyema by video-assisted thoracoscopy (VATS) and insertion of thoracic suction drains was performed, accompanied by targeted antibiotic therapy. Over a course of 6 weeks, the patient recovered completely. The case report illustrates severe infectious side effects of major dental interventions, and it critically summarizes current dental guideline recommendations on peri-interventional antimicrobial therapy. Therefore, a good clinical follow up after major tooth extractions is imperative.
Topics: Actinomyces viscosus; Adult; Anti-Bacterial Agents; Bacterial Infections; Drainage; Empyema, Pleural; Humans; Liver Abscess; Male; Pleura; Postoperative Complications; Prevotella intermedia; Streptococcus anginosus; Streptococcus constellatus; Thoracic Surgery, Video-Assisted; Thoracoscopy; Tooth Extraction; Treatment Outcome
PubMed: 31083748
DOI: 10.1055/a-0829-7017 -
Journal of Asian Natural Products... Jun 2020A new lignan glycoside, astrayunoside A (), along with eight known compounds (), were obtained from the methanol extract of roots of . All the compounds were obtained...
A new lignan glycoside, astrayunoside A (), along with eight known compounds (), were obtained from the methanol extract of roots of . All the compounds were obtained from for the first time. Their structures were elucidated by extensive spectroscopic analysis (1D and 2D-NMR, MS, UV, CD, and IR). The weak antibacterial activities of the crude extracts of against , , , , , H901, , and were observed.
Topics: Anti-Bacterial Agents; Glycosides; Lignans; Microbial Sensitivity Tests; Molecular Structure; Plant Extracts
PubMed: 31045439
DOI: 10.1080/10286020.2019.1607840 -
Letters in Applied Microbiology Apr 2019Candida-associated denture stomatitis presents as erythema of the palatal mucosa and is caused by biofilms containing the fungus Candida albicans that co-reside with...
Candida-associated denture stomatitis presents as erythema of the palatal mucosa and is caused by biofilms containing the fungus Candida albicans that co-reside with oral bacteria on the denture-fitting surface. This study aimed to assess the effect of several frequently encountered oral bacteria on the expression of C. albicans virulence factors in in vitro polymicrobial biofilms. Biofilms containing C. albicans and selected bacterial species were grown on denture acrylic, and analysed by microscopy and by qPCR for expression of putative virulence genes. Candida albicans-only biofilms showed limited hyphal production. Hyphal development was significantly (P < 0·001) increased when biofilms also contained four species of oral bacteria (Streptococcus sanguinis, Streptococcus gordonii, Actinomyces odontolyticus and Actinomyces viscosus), as was the expression of virulence genes (P < 0·05). Importantly, inclusion of Porphyromonas gingivalis in the biofilm consortium resulted in significant (P < 0·05) inhibition of virulence gene expression and production of hyphae. The in vitro expression of C. albicans virulence factors was modulated in polymicrobial biofilms. The complexity of this modulation was highlighted by the reversal of effects following introduction of a single bacterial species into a biofilm community. SIGNIFICANCE AND IMPACT OF THE STUDY: The impact of individual bacterial species on Candida albicans virulence highlights both the complexity of predicting infection mediated by polymicrobial communities and the potential for management through pro- or prebiotic therapy. The possibility to selectively modulate microbial virulence by addition of, or treatment with pro- or prebiotics avoids the use of conventional antimicrobial compounds, thus reducing the contribution to potential drug resistance. Understanding which bacterial species modulate virulence, and the mechanisms by which this occurs, particularly in biofilms, provides excellent foundations for further research questions, and the potential for novel clinical interventions.
Topics: Actinomyces; Biofilms; Candida albicans; Gene Expression Regulation, Fungal; Hyphae; Mouth; Porphyromonas gingivalis; Stomatitis, Denture; Streptococcus; Virulence; Virulence Factors
PubMed: 30825340
DOI: 10.1111/lam.13145