Optimized Electrophoretic Deposition of Chitosan/Mesoporous Glass Nanoparticles with Gentamicin on Titanium Implants: Enhancing Hemocompatibility and Antibacterial Activity.

Titanium-based implants have long been studied and used for applications in bone tissue engineering, thanks to their outstanding mechanical properties and appropriate biocompatibility. However, many implants struggle with osseointegration and attachment and can be vulnerable to the development of infections. In this work, we have developed a composite coating via electrophoretic deposition, which is both bioactive and antibacterial. Mesoporous bioactive glass particles with gentamicin were electrophoretically deposited onto a titanium substrate. In order to validate the hypothesis that the quantity of particles in the coatings is sufficiently high and uniform in each deposition process, an easy-to-use image processing algorithm was designed to minimize human dependence and ensure reproducible results. The addition of loaded mesoporous particles did not affect the good adhesion of the coating to the substrate although roughness was clearly enhanced. After 7 days of immersion, the composite coatings were almost dissolved and released, but phosphate-related compounds started to nucleate at the surface. With a simple and low-cost technique like electrophoretic deposition, and optimized stir and suspension times, we were able to synthesize a hemocompatible coating that significantly improves the antibacterial activity when compared to the bare substrate for both Gram-positive and Gram-negative bacteria.

Antibacterial Effects of Silver Diamine Fluoride with and without Potassium Iodide against Streptococcus mutans.

Introduction: Silver diamine fluoride (SDF) is a topical treatment for carious lesions and a primary preventative for newly exposed high-risk surfaces such as fissures and roots in the first molars. Using potassium iodide (KI) after applying SDF has been recommended as a way of reducing the severity of black staining, as well as preserving its antibacterial effect useful in deep caries. Objective: The objective of this research was to compare the antibacterial effect of SDF, with and without KI, on Streptococcus mutans (S. mutans) and dental biofilm. Methods: The antibacterial effects of SDF, KI, and the combination of both were measured using three different techniques (inhibition halo, minimum inhibitory effect [MIE], and colony-forming unit [CFU], testing). Results: The results were then subjected to statistical analysis. Analyzed by means of the Kruskal-Wallis statistical test, the inhibition halos yielded a value of P = 0.3309. Using the MIE test, only the SDF treatment produced an antibacterial effect, at 10%, compared to the KI group, with P = 0.001. Finally, the CFU test revealed a total absence of colonies for all three reagents. All three substances analyzed achieved total inhibition of S. mutans. SDF is effective even in its minimal commercial concentration. Its antibacterial capacity decreases with the addition of KI. Conclusions: The three substances analyzed at their maximum concentrations exhibited an antibacterial effect against S. mutans, resulting in total inhibition.

Silver Nanoparticles: Multifunctional Tool in Environmental Water Remediation.

Water pollution is a worldwide environmental and health problem that requires the development of sustainable, efficient, and accessible technologies. Nanotechnology is a very attractive alternative in environmental remediation processes due to the multiple properties that are conferred on a material when it is at the nanometric scale. This present review focuses on the understanding of the structure-physicochemical properties-performance relationships of silver nanoparticles, with the objective of guiding the selection of physicochemical properties that promote greater performance and are key factors in their use as antibacterial agents, surface modifiers, colorimetric sensors, signal amplifiers, and plasmonic photocatalysts. Silver nanoparticles with a size of less than 10 nm, morphology with a high percentage of reactive facets {111}, and positive surface charge improve the interaction of the nanoparticles with bacterial cells and induce a greater antibacterial effect. Adsorbent materials functionalized with an optimal concentration of silver nanoparticles increase their contact area and enhance adsorbent capacity. The use of stabilizing agents in silver nanoparticles promotes selective adsorption of contaminants by modifying the surface charge and type of active sites in an adsorbent material, in addition to inducing selective complexation and providing stability in their use as colorimetric sensors. Silver nanoparticles with complex morphologies allow the formation of hot spots or chemical or electromagnetic bonds between substrate and analyte, promoting a greater amplification factor. Controlled doping with nanoparticles in photocatalytic materials produces improvements in their electronic structural properties, promotes changes in charge transfer and bandgap, and improves and expands their photocatalytic properties. Silver nanoparticles have potential use as a tool in water remediation, where by selecting appropriate physicochemical properties for each application, their performance and efficiency are improved.

Activity of extracts and terpenoids from Tontelea micrantha (Mart. ex Schult.) A.C.Sm. (Celastraceae) against pathogenic bacteria.

The pharmacological properties of plant extracts and phytochemicals, such as flavonoids and terpenoids, remain of great interest. In this work, the effect of extracts, friedelan-3,21-dione, and 3ß-O-D-glucosyl-sitosterol isolated from Tontelea micrantha roots was evaluated against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Klebsiella oxytoca and Escherichia coli. The antibacterial activity was evaluated by the minimum inhibitory and bactericidal concentrations (MIC and MBC, respectively), and the synergistic effect was assessed by the Checkerboard assay. Furthermore, the cytotoxicity of the plant-derived compounds against Vero cells was measured by the 3-(4 5-dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromide (MTT) method. The biological effects of the isolated compounds were predicted using the PASS online software. The chloroform and hexane extracts of T. micrantha roots showed promising antibacterial effect, with MIC in the range of 4.8-78.0 µg/mL. Further analyses showed that these compounds do not affect the integrity of the membrane. The combination with streptomycin strongly reduced the MIC of this antibiotic and extracts. The extracts were highly toxic to Vero cells, and no cytotoxicity was detected for the two terpenoids isolated from them (i.e. friedelan-3,21-dione and 3ß-O-D-glucosyl-sitosterol; CC50 > 1000 µg/mL). Therefore, extracts obtained from T. micrantha roots significantly inhibited bacterial growth and are considered promising agents against pathogenic bacteria. The cytotoxicity results were very relevant and can be tested in bioassays.

Assessment of Polydopamine to Reduce Streptococcus mutans Adhesion to a Dental Polymer.

Bacterial adhesion to the surface of materials is the first step in biofilm formation, which will lead to conditions that may compromise the health status of patients. Recently, polydopamine (PDA) has been proposed as an antibacterial material. Therefore, the objective of the current work was to assess and compare the adhesion of Streptococcus mutans to the surface of poly(methyl methacrylate) (PMMA) discs that were modified using PDA following a biomimetic approach versus smooth PDA-coated PMMA surfaces. In addition, an assessment of the growth inhibition by PDA was performed. PMMA discs were manufactured and polished; soft lithography, using the topography from the Crocosmia aurea leaf, was used to modify their surface. PDA was used to smooth-coat PMMA discs by dip-coating. The growth inhibition was measured using an inhibition halo. The surfaces were characterized by means of atomic force microscopy (AFM), the contact angle (CA), and Fourier-transform infrared spectroscopy (FTIR). Polydopamine exhibited a significant antibacterial effect when used directly on the S. mutans planktonic cells, but such an effect was not as strong when modifying the PMMA surfaces. These results open the possibility of using polydopamine to reduce the adhesion and growth of S. mutans, which might have important consequences in the dental field.

Structural characterization of a galectin from the marine sponge Aplysina lactuca (ALL) with synergistic effects when associated with antibiotics against bacteria.

Lectins presents the ability to interact with glycans and trigger varied responses, including the inhibition of the development of various pathogens. Structural studies of these proteins are essential to better understand their functions. In marine sponges, so far only a few lectins have their primary structures completely determined. Thus, the objective of this work was to structurally characterize and evaluate antibacterial potential, in association with different antibiotics, of the lectin isolated from the marine sponge Aplysina lactuta (ALL). ALL is a homotetramer of 60 kDa formed by four 15 kDa-subunits. The lectin showed affinity only for the glycoproteins fetuin, asialofetuin, mucin type III, and bovine submaxillary mucin type I. The complete amino acid sequences of two isoforms of ALL, named ALL-a and ALL-b, were determined by a combination of Edman degradation and overlapped peptides sequenced by tandem mass spectrometry. ALL-a and ALL-b have 144 amino acids with molecular masses of 15,736 Da and 15,985 Da, respectively. Both structures contain conserved residues typical of the galectin family. ALL is a protein with antibacterial potential, when in association with ampicillin and oxacillin the lectin potentiates its antibiotic effect, included Methicillin-resistant Staphylococcus strains. Thus, ALL shows to be a molecule with potential for the development of new antibacterial drugs.

Efecto antibacteriano del extracto hidroalcohólico de Solanum sessiliflorum Dunal (cocona) sobre Streptococcus mutans

Introducción: La búsqueda de nuevos extractos de origen vegetal con propiedades antibacterianas para mantener la salud bucal, es fundamental para el óptimo desempeño del personal militar. Objetivos: Evaluar el efecto antibacteriano del extracto hidroalcohólico de Solanum sessiliflorum Dunal (cocona) sobre Streptococcus mutans. Métodos: Estudio experimental in vitro y comparativo. Se realizó un ensayo fitoquímico preliminar del extracto hidroalcohólico de Solanum sessiliflorum Dunal. Se emplearon 48 placas de agar Müller-Hinton (Merck®), distribuidas en 6 grupos (n= 8): grupo I (agua destilada), grupo II (etanol al 70 %), grupo III (clorhexidina al 0,12 %), grupo IV (Solanum sessiliflorum Dunal al 25 %), grupo V (Solanum sessiliflorum Dunal al 50 %) y grupo VI (Solanum sessiliflorum Dunal al 75 %). Se utilizó la técnica de difusión con discos descrita por Bauer y Kirby; la cepa empleada fue Streptococcus mutans ATCC 25175 y las mediciones de los halos de inhibición se realizaron a las 24 horas, para determinar la actividad antibacteriana. Resultados: En el ensayo fitoquímico se detectaron compuestos fenólicos, antocianinas, quinonas y glicósidos cardiotónicos. Se comprobó el efecto antibacteriano del grupo VI (Solanum sessiliflorum Dunal al 75 %) con 19,831 ± 0,0553 mm (99,37 %), comparable con el de clorhexidina al 0,12 % (grupo III) 19,956 ± 0,0431 mm (100 %) sobre Streptococcus mutans ATCC 25175. Conclusiones: El extracto hidroalcohólico de Solanum sessiliflorum Dunal al 75 % presenta efecto antibacteriano in vitro sobre cepas de Streptococcus mutans ATCC 25175 con valores similares a clorhexidina al 0,12 % .

Introduction: The search for new extracts of plant origin with antibacterial properties to maintain oral health is essential for the optimal performance of military personnel. Objectives: To evaluate the antibacterial effect of the hydroalcoholic extract of Solanum sessiliflorum Dunal (cocona) on Streptococcus mutans. Methods: In vitro and comparative experimental study. A preliminary phytochemical assay of the hydroalcoholic extract of Solanum sessiliflorum Dunal was performed. Forty-eight Müller-Hinton agar plates (Merck®) were used, distributed in 6 groups (n= 8). Group I (distilled water), group II (70% ethanol), group III (0.12% chlorhexidine), group IV (25% Solanum sessiliflorum Dunal), group V (50% Solanum sessiliflorum Dunal) and group VI (75% Solanum sessiliflorum Dunal); the disc diffusion technique described by Bauer and Kirby was used; the strain used was Streptococcus mutans ATCC 25175 and the inhibition halos were measured at 24 hours to determine the antibacterial activity. Results: Phenolic compounds, anthocyanins, quinones and cardiotonic glycosides were detected in the phytochemical assay. The antibacterial effect of group VI (Solanum sessiliflorum Dunal 75%) was proven with 19,831 ± 0,0553 mm (99,37%), comparable to that of 0,12% chlorhexidine (group III) 19,956 ± 0,0431 mm (100%) on Streptococcus mutans ATCC 25175. Conclusions: The 75% hydroalcoholic extract of Solanum sessiliflorum Dunal shows in vitro antibacterial effect on Streptococcus mutans ATCC 25175 strains with values similar to 0,12% chlorhexidine.

Antibacterial effect, cytotoxicity, and bond strength of a modified dental adhesive containing silver nanoparticles.

This study aimed to evaluate the antibacterial effect, cytotoxicity, and microtensile bond strength of an adhesive system containing silver nanoparticles (NAg). NAg was synthesized and incorporated (500 and 1000 ppm) into Scotchbond Multi-Purpose (SBMP) primer and bond. A microtensile bond test (µTBS) was performed after 24 h and 1 year. The adhesive interface was characterized using a confocal Raman microscope. The antibacterial activity was assessed using agar diffusion and biofilm inhibition assays (S. mutans). MTT assay was used to assess the cytotoxicity of NAg-conditioned culture media on human dental pulp stem cells (hDPSCs). The results were statistically analyzed using analysis of variance and Tukey's tests (α = .01). Incorporating 500 and 1000 ppm of NAg in the SBMP did not affect the µTBS after 24 h (p > 0.05). However, in the 1 year evaluation, 500 ppm presented the highest µTBS values (p < 0.05). The addition of NAg at 500 and 1000 ppm in the primer and bond led to larger inhibition halos and colony-forming units than the control (p < 0.05). For the unpolymerized and polymerized groups, the combination of primer and bond presented the highest cytotoxic effects on hDPSCs (p < 0.05). In conclusion, incorporating 500 or 1000 ppm of NAg into an etch-and-rinse adhesive system led to an antibacterial effect without altering the cytotoxicity. SBMP at 500 ppm presented a higher µTBS at 1 year.

Spectral analysis and Antibacterial activity of the bioactive principles of Sargassum tenerrimum J. Agardh collected from the Red sea, Jazan, Kingdom of Saudi Arabia

Abstract Seaweeds are a major marine resource that can be explored to develop novel pharmaceutical molecules. The present study showed the presence of unique bioactive components in the petroleum ether extract (PEE) and methanolic extract (ME) of Sargassum tenerrimum. The gas chromatography-mass spectrometry analysis suggested that the PEE of S. tenerrimum contained antibacterial biomolecules: hexadecanoic acid, methyl ester, 17-pentatriacontene, dasycarpidan-1-methanol, and acetate (ester). However, the ME of S. tenerrimum exhibited better antibacterial effect than the PEE due to the presence of the bioactive compounds 1,2-benzenedicarboxylic acid, diisooctyl ester, tetratetracontane, 1-docosene, 1,2-benzenediol, and benzoic acid. Thus, promising antibacterial molecules can be isolated from S. tenerrimum for better therapeutic use.

Resumo As algas marinhas são um importante recurso marinho que pode ser explorado para desenvolver novas moléculas farmacêuticas. O presente estudo mostrou a presença de componentes bioativos únicos no extrato etéreo de petróleo (PEE) e no extrato metanólico (ME) de Sargassum tenerrimum. A análise por cromatografia gasosa-espectrometria de massa sugeriu que o PEE de S. tenerrimum continha biomoléculas antibacterianas: ácido hexadecanoico, éster metílico, 17-pentatriaconteno, dasycarpidan-1-metanol e acetato (éster). Entretanto, o ME de S. tenerrimum exibiu melhor efeito antibacteriano do que o PEE devido à presença dos compostos bioativos ácido 1,2-benzenodicarboxílico, éster diisooctil, tetratetracontano, 1-docosene, 1,2-benzoenodiol e ácido benzoico. Assim, moléculas antibacterianas promissoras podem ser isoladas de S. tenerrimum para melhor uso terapêutico.

Spectral analysis and Antibacterial activity of the bioactive principles of Sargassum tenerrimum J. Agardh collected from the Red sea, Jazan, Kingdom of Saudi Arabia / Análise espectral e atividade antibacteriana dos princípios bioativos de Sargassum tenerrimum J. Agardh coletados no mar Vermelho, Jazan, Reino da Arábia Saudita

Abstract Seaweeds are a major marine resource that can be explored to develop novel pharmaceutical molecules. The present study showed the presence of unique bioactive components in the petroleum ether extract (PEE) and methanolic extract (ME) of Sargassum tenerrimum. The gas chromatography-mass spectrometry analysis suggested that the PEE of S. tenerrimum contained antibacterial biomolecules: hexadecanoic acid, methyl ester, 17-pentatriacontene, dasycarpidan-1-methanol, and acetate (ester). However, the ME of S. tenerrimum exhibited better antibacterial effect than the PEE due to the presence of the bioactive compounds 1,2-benzenedicarboxylic acid, diisooctyl ester, tetratetracontane, 1-docosene, 1,2-benzenediol, and benzoic acid. Thus, promising antibacterial molecules can be isolated from S. tenerrimum for better therapeutic use.

Resumo As algas marinhas são um importante recurso marinho que pode ser explorado para desenvolver novas moléculas farmacêuticas. O presente estudo mostrou a presença de componentes bioativos únicos no extrato etéreo de petróleo (PEE) e no extrato metanólico (ME) de Sargassum tenerrimum. A análise por cromatografia gasosa-espectrometria de massa sugeriu que o PEE de S. tenerrimum continha biomoléculas antibacterianas: ácido hexadecanoico, éster metílico, 17-pentatriaconteno, dasycarpidan-1-metanol e acetato (éster). Entretanto, o ME de S. tenerrimum exibiu melhor efeito antibacteriano do que o PEE devido à presença dos compostos bioativos ácido 1,2-benzenodicarboxílico, éster diisooctil, tetratetracontano, 1-docosene, 1,2-benzoenodiol e ácido benzoico. Assim, moléculas antibacterianas promissoras podem ser isoladas de S. tenerrimum para melhor uso terapêutico.

Spectral analysis and Antibacterial activity of the bioactive principles of Sargassum tenerrimum J. Agardh collected from the Red sea, Jazan, Kingdom of Saudi Arabia / Análise espectral e atividade antibacteriana dos princípios bioativos de Sargassum tenerrimum J. Agardh coletados no mar Vermelho, Jazan, Reino da Arábia Saudita

Seaweeds are a major marine resource that can be explored to develop novel pharmaceutical molecules. The present study showed the presence of unique bioactive components in the petroleum ether extract (PEE) and methanolic extract (ME) of Sargassum tenerrimum. The gas chromatography-mass spectrometry analysis suggested that the PEE of S. tenerrimum contained antibacterial biomolecules: hexadecanoic acid, methyl ester, 17-pentatriacontene, dasycarpidan-1-methanol, and acetate (ester). However, the ME of S. tenerrimum exhibited better antibacterial effect than the PEE due to the presence of the bioactive compounds 1,2-benzenedicarboxylic acid, diisooctyl ester, tetratetracontane, 1-docosene, 1,2-benzenediol, and benzoic acid. Thus, promising antibacterial molecules can be isolated from S. tenerrimum for better therapeutic use.

As algas marinhas são um importante recurso marinho que pode ser explorado para desenvolver novas moléculas farmacêuticas. O presente estudo mostrou a presença de componentes bioativos únicos no extrato etéreo de petróleo (PEE) e no extrato metanólico (ME) de Sargassum tenerrimum. A análise por cromatografia gasosa espectrometria de massa sugeriu que o PEE de S. tenerrimum continha biomoléculas antibacterianas: ácido hexadecanoico, éster metílico, 17-pentatriaconteno, dasycarpidan-1-metanol e acetato (éster). Entretanto, o ME de S. tenerrimum exibiu melhor efeito antibacteriano do que o PEE devido à presença dos compostos bioativos ácido 1,2-benzenodicarboxílico, éster diisooctil, tetratetracontano, 1-docosene, 1,2-benzoenodiol e ácido benzoico. Assim, moléculas antibacterianas promissoras podem ser isoladas de S. tenerrimum para melhor uso terapêutico.

Spectral analysis and Antibacterial activity of the bioactive principles of Sargassum tenerrimum J. Agardh collected from the Red sea, Jazan, Kingdom of Saudi Arabia / Análise espectral e atividade antibacteriana dos princípios bioativos de Sargassum tenerrimum J. Agardh coletados no mar Vermelho, Jazan, Reino da Arábia Saudita

Seaweeds are a major marine resource that can be explored to develop novel pharmaceutical molecules. The present study showed the presence of unique bioactive components in the petroleum ether extract (PEE) and methanolic extract (ME) of Sargassum tenerrimum. The gas chromatography-mass spectrometry analysis suggested that the PEE of S. tenerrimum contained antibacterial biomolecules: hexadecanoic acid, methyl ester, 17-pentatriacontene, dasycarpidan-1-methanol, and acetate (ester). However, the ME of S. tenerrimum exhibited better antibacterial effect than the PEE due to the presence of the bioactive compounds 1,2-benzenedicarboxylic acid, diisooctyl ester, tetratetracontane, 1-docosene, 1,2-benzenediol, and benzoic acid. Thus, promising antibacterial molecules can be isolated from S. tenerrimum for better therapeutic use.(AU)

As algas marinhas são um importante recurso marinho que pode ser explorado para desenvolver novas moléculas farmacêuticas. O presente estudo mostrou a presença de componentes bioativos únicos no extrato etéreo de petróleo (PEE) e no extrato metanólico (ME) de Sargassum tenerrimum. A análise por cromatografia gasosa espectrometria de massa sugeriu que o PEE de S. tenerrimum continha biomoléculas antibacterianas: ácido hexadecanoico, éster metílico, 17-pentatriaconteno, dasycarpidan-1-metanol e acetato (éster). Entretanto, o ME de S. tenerrimum exibiu melhor efeito antibacteriano do que o PEE devido à presença dos compostos bioativos ácido 1,2-benzenodicarboxílico, éster diisooctil, tetratetracontano, 1-docosene, 1,2-benzoenodiol e ácido benzoico. Assim, moléculas antibacterianas promissoras podem ser isoladas de S. tenerrimum para melhor uso terapêutico.(AU)

Dual action of pyroligneous acid in the eco-friendly synthesis of bactericidal silver nanoparticles.

In the present study, we demonstrate that pyroligneous acid (PA), also known as wood vinegar, functions efficiently as both reducing and stabilizing agent in the synthesis of silver nanoparticles (AgNPs). The synthesis and stabilization of AgNPs take place in the following fashion: 1) in alkaline environment, oxygenated species (phenols in the present case) contained in PA reduce silver ions to metallic silver; 2) acetic acid, abundantly present in PA, adsorb onto the AgNPs conferring electrostatic stabilization. This mechanism is supported by GC-MS and RAMAN analysis, with the former revealing the compounds lacking in PA after nanoparticle synthesis and the latter demonstrating acetic acid adsorbed on the nanoparticles. The AgNPs produced via this method were quite stable up to 150 days (zeta potential = -56 mV). The AgNPs were then found to inhibit the growth of Escherichia coli and Staphylococcus aureus. Concerning PA, we showed that it displays bactericidal properties only under acidic conditions. This study contributes to the development of more environmentally benign routes to produce nanomaterials.

Antibacterial and antifungal capacity of three commercially available mouthwashes with different concentrations of chlorhexidine / Efecto antibacteriano y antifúngico de tres enjuagues bucales comerciales con diferentes concentraciones de clorhexidina

Abstract Chlorhexidine was introduced almost seven decades ago and has a myriad of applications in dentistry. Few studies have evaluated the antimicrobial and antifungal capacity of different concentrations of chlorhexidine mouthwashes. Therefore, the aim of this study, was to evaluate in vitro, the antibacterial and antifungal capacity of three commercially available mouthwashes in Costa Rica, with different concentrations of chlorhexidine, 0.12%, 0.06%, and 0.03%. The experimental method selected was the Kirby-Bauer method to evaluate the antibacterial and antifungal effect of each compound by measuring the inhibitory effect on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans strains, exposed to the antiseptic solutions. All samples showed some degree of antibacterial and antifungal effect. Even though we provide in vitro results, our findings are of relevance since all the species used in our experiment are microorganisms that may be present in dental plaque. Our results further support evidence that oral hygiene regimens may include mouthwashes with low doses of chlorhexidine and maintain reasonable antibacterial and antifungal efficacy.

Resumen La clorhexidina se introdujo hace casi siete décadas y tiene una gran variedad de aplicaciones en odontología. Pocos estudios han evaluado la capacidad antimicrobiana y antifúngica de diferentes concentraciones de enjuagues bucales con clorhexidina. Por lo tanto, el objetivo de este estudio fue evaluar in vitro, la capacidad antibacteriana y antifúngica de tres enjuagues bucales disponibles comercialmente en Costa Rica, con diferentes concentraciones de clorhexidina, 0.12%, 0.06% y 0.03%. El método experimental seleccionado fue el método Kirby-Bauer para evaluar el efecto antibacteriano y antifúngico de cada compuesto midiendo el efecto inhibidor sobre Staphylococcus aureus, Enterococcus faecalis, Escherichia coli y Candida albicans, expuestos a la solución antiséptica. Todas las muestras mostraron algún grado de efecto antibacteriano y antifúngico. Aunque proporcionamos resultados in vitro, nuestros hallazgos son de relevancia, ya que todas las especies utilizadas en nuestro experimento son microorganismos que pueden estar presentes en la placa dental. Nuestros resultados respaldan aún más la evidencia de que los regímenes de higiene bucal pueden incluir enjuagues bucales con dosis bajas de clorhexidina y mantener una eficacia antibacteriana y antifúngica razonable.

Antimicrobial activity of supernatants produced by bacteria isolated from Brazilian stingless bee's larval food.

BACKGROUND: The discovery of new molecules with antimicrobial properties has been a promising approach, mainly when related to substances produced by bacteria. The use of substances produced by bees has evidenced the antimicrobial action in different types of organisms. Thus, the use of bacteria isolated from larval food of stingless bees opens the way for the identification of the new molecules. The effect of supernatants produced by these bacteria was evaluated for their ability to inhibit the growth of bacteria of clinical interest. Furthermore, their effects were evaluated when used in synergy with antibiotics available in the pharmaceutical industry. RESULTS: A few supernatants showed an inhibitory effect against susceptible and multiresistant strains in the PIC assay and the modulation assay. Emphasizing the inhibitory effect on multidrug-resistant strains, 7 showed an effect on multidrug-resistant Escherichia coli (APEC), Klebsiella pneumoniae carbapenemase (KPC), multidrug-resistant Pseudomonas aeruginosa, and multidrug-resistant Staphylococcus aureus (MRSA) in the PIC assay. Of the supernatants analyzed, some presented synergism for more than one species of multidrug-resistant bacteria. Nine had a synergistic effect with ampicillin on E. coli (APEC) or S. aureus (MRSA), 5 with penicillin G on E. coli (APEC) or KPC, and 3 with vancomycin on KPC. CONCLUSION: In summary, the results indicate that supernatants produced from microorganisms can synthesize different classes of molecules with potent antibiotic activity against multiresistant bacteria. Thus, suggesting the use of these microorganisms for use clinical tests to isolate the molecules produced and their potential for use.

Silver nanoparticles synthesized by the heavy metal resistant strain Amycolatopsis tucumanensis and its application in controlling red strip disease in sugarcane.

The production of bioethanol and sugar from sugarcane is an important economic activity in several countries. Sugarcane is susceptible to different phytopathogens. Over the last years, the red stripe disease caused by the bacterium Acidovorax avenae subsp. avenae produced significant losses in sugarcane crops. Bio-nanotechnology emerged as an eco-friendly alternative to the biosynthesis of antimicrobial molecules. The aims of this study were to (a) produce extracellular silver nanoparticles using the heavy metal resistant strain Amycolatopsis tucumanensis, (b) evaluate their antibacterial in vitro effect and (c) determine the potential of silver nanoparticles to protect sugarcane against red stripe disease. Amycolatopsis tucumanensis synthesized spherical silver nanoparticles with an average size of 35 nm. Nanoparticles were able to control the growth of A. avenae subsp. avenae in in vitro assays. In addition, in vivo assays in sugarcane showed a control upon the red stripe disease when silver nanoparticles were applied as preventive treatment. The Disease Severity Index was 28.94% when silver nanoparticles were applied 3 days before inoculation with A. avenae subsp. a venae. To our knowledge, this is the first report of silver nanoparticles extracellularly synthesized by an Amycolatopsis strain that were able to inhibited the growth of A. avenae subsp. avenae and control the red stripe disease in sugarcane.

Bacteriostatic effect of Echeveria extracts on diarrheagenic E. coli pathotypes and non-cytotoxicity on human Caco-2 cells.

INTRODUCTION: Diarrheagenic Escherichia coli pathotypes are important aetiological agents of diarrhoeal illness among children from less developed areas, worldwide. Diarrheagenic E. coli pathotypes strains are increasingly becoming drug resistant, thus effective and accessible therapeutic alternatives are required for their treatment; herbal extracts may be a potential alternative. AIMS: to evaluate Echeveria craigiana, E. kimnachii, and E. subrigida methanol extracts antibacterial effect on six diarrheagenic E. coli reference strains and on human colorectal adenocarcinoma cells viability and cytokine production. METHODOLOGY: Diarrheagenic E. coli pathotypes reference strains: typical enteropathogenic E2348/69, enterotoxigenic H10407, enterohaemorrhagic O157:H7/EDL933, enteroinvasive E11, diffusely adherent C18451-A, and enteroaggregative 042 E. coli. E craigiana, E. kimnachii, and E. subrigida leaves, collected at Sinaloa, Mexico, were freeze-dried and macerated in methanol solvent. Antibacterial activity was determined by a novel method developed in our laboratory, bacterial oxygen consumption by polarographic oxygen electrode technique and membrane integrity by two methods (live/dead and protein leakage assays). Colorectal adenocarcinoma cells viability by MTT assay and cytokine production using a Cytometric Bead Array kit. RESULTS: Extracts concentrations of 100 µg/mL and 5-hour incubation, reduced more than 93% the growth of all diarrheagenic E. coli pathotypes tested strains and significantly decreased bacterial oxygen consumption, like bacteriostatic antibiotics. After 24-hour incubation methanol extracts had a differential antibacterial effect on each diarrheagenic E. coli pathotypes strain. Echeveria extracts did not have any effect on viability and cytokine production of colorectal adenocarcinoma cells. CONCLUSIONS: Echeveria methanol extracts have a bacteriostatic effect on all diarrheagenic E. coli pathotypes strains, thus potentially they could be used as antibacterial agents on diarrheagenic E. coli pathotypes-contaminated products and on patients with diarrheagenic E. coli pathotypes infections.

Preparation and in vitro evaluation of Vancomycin loaded Montmorillonite-Sodium Alginate topical gel for wound infection

Abstract Despite decades of research, wound healing remains a significant public health problem. This study aimed to develop and evaluate a topical sodium alginate gel containing vancomycin (Van) loaded MMT NPs for wound healing applications. Van was loaded in MMT at different conditions (pHs of 6, 7 and temperatures of 40, 50 °C) (Van/MMT NPs). The optimum formulation (with the smallest particle size and a high value of zeta potential; 270.8 ± 77.35 nm and -35.96 ± 2.73, respectively) showed a high drug-loading capacity (entrapment efficacy of 96%) and a sustained release pattern of Van (95%) over 480 min. The optimum Van/MMT NPs were embedded into the sodium alginate (SA) gel (Van/MMT NPs/SA gel). The Van/ MMT NPs/SA gel showed a sustained and slow release pattern of Van (95%) over 50 h. FTIR tests revealed the electrostatic interaction between MMT and Van. The broth macrodilution tube method was used to determine the minimum inhibitory concentration (MIC) of Van, Van/ MMT NPs, and Van/MMT NPs/SA gel against Staphylococcus aureus. The results showed the promising antibacterial activity of Van/MMT NPs/SA gel, thus, this gel can be a promising formulation for the management of infected wounds

Cytotoxicity and antibacterial activity of bleached turmeric hydro-alcoholic extract versus sodium hypochlorite as an endodontic irrigant: in vitro study / Citotoxicidade e atividade antibacteriana do extrato hidroalcoólico de cúrcuma branqueado versus hipoclorito de sódio como irrigante endodôntico: estudo in vitro

Objetivo: Avaliar a citotoxicidade e o efeito antibacteriano do extrato hidroalcoólico de cúrcuma branqueado comparado ao hipoclorito de sódio como irrigante endodôntico. Material e Métodos: A citotoxicidade foi avaliada em fibroblastos de pele humana usando o ensaio MTT. Os irrigantes foram testados em intervalos de tempo de 1, 5 e 15 minutos. Após o tempo de contato, a solução de MTT foi adicionada e as placas de poços foram incubadas. Após o período de incubação, a densidade óptica foi lida e correlacionada com a porcentagem de viabilidade celular. A eficiência antibacteriana foi avaliada usando o teste de contato direto. Cada irrigante endodôntico foi adicionado à suspensão fresca de Enterococcus faecalis e ao meio de infusão cérebro-coração e então incubados por 48 horas. Após o período de incubação, as leituras de densidade óptica foram obtidas e lidas por leitor de ELISA a 620 nm. Resultados: Os resultados do teste de citotoxicidade revelaram que o extrato de cúrcuma branqueado apresentou porcentagem de viabilidade celular significativamente maior do que o hipoclorito de sódio (NaOCl) em todos os intervalos de tempo (p<0,001). No entanto, no grupo de intervenção, a porcentagem de viabilidade celular diminuiu significativamente ao longo do tempo. Os resultados do teste antibacteriano mostraram inibição bacteriana por ambos os grupos com diferença não significativa entre os dois grupos testados (p<0,05). Conclusão:O extrato hidroalcoólico de cúrcuma branqueado pode representar uma alternativa fitoterápica irrigante endodôntico para evitar os efeitos tóxicos indesejáveis do NaOCl devido à sua menor citotoxicidade e efeito antibacteriano proeminente contra Enterococcus faecalis (AU)

Objective: To evaluate the cytotoxicity and antibacterial effect of bleached turmeric hydro-alcoholic extract compared to sodium hypochlorite as an endodontic irrigant. Material and Methods: Cytotoxicity was evaluated on human skin fibroblasts using MTT assay. The irrigants were tested at 1, 5- and 15-minutes time intervals. After contact time, MTT solution was added and well plates were incubated. After the incubation period, optical density was read and correlated with cell viability percent. Antibacterial efficiency was evaluated using direct contact test. Each endodontic irrigant was added to fresh Enterococcus faecalis suspension and brain heart infusion media then incubated for 48 hours. After incubation period, optical density readings were obtained and read by ELISA reader at 620 nm. Results:Results of cytotoxicity test revealed that bleached turmeric extract had significant higher cell viability percent than Sodium hypochlorite (NaOCl) at all time intervals (p<0.001). However, in the intervention group, cell viability percent significantly decreased over time. Results of antibacterial test showed bacterial inhibition by both groups with non-significant difference between the two tested groups (p<0.05). Conclusion: Bleached turmeric hydro-alcoholic extract can represent an herbal alternative endodontic irrigant to avoid the undesirable toxic effects of NaOCl due to its less cytotoxicity and prominent antibacterial effect against Enterococcus faecalis. (AU)

Antibacterial Potential by Rupture Membrane and Antioxidant Capacity of Purified Phenolic Fractions of Persea americana Leaf Extract.

The present research focused on evaluating the antibacterial effect and the mechanism of action of partially purified fractions of an extract of Persea americana. Furthermore, both its antioxidant capacity and composition were evaluated. The extract was fractionated by vacuum liquid chromatography. The antimicrobial effect against Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 11229), Pseudomonas aeruginosa (ATCC 15442), and Salmonella choleraesuis (ATCC 1070) was analyzed by microdilution and the mechanism of action by the Sytox green method. The antioxidant capacity was determined by DPPH, FRAP, and ABTS techniques and the composition by Rp-HPLC-MS. All fractions showed a concentration-dependent antibacterial effect. Fractions F3, F4, and F5 (1000 µg/mL) showed a better antibacterial effect than the extract against the bacteria mentioned. The F3 fraction showed inhibition of 95.43 ± 3.04% on S. aureus, F4 showed 93.30 ± 0.52% on E. coli, and F5 showed 88.63 ± 1.15% on S. choleraesuis and 86.46 ± 3.20% on P. aeruginosa. The most susceptible strain to the treatment with the extract was S. aureus. Therefore, in this strain, the bacterial membrane damage induced by the extract and fractions was evidenced by light fluorescence microscopy. Furthermore, the extract had better antioxidant action than each fraction. Finally, sinensitin was detected in F3 and cinnamoyl glucose, caffeoyl tartaric acid, and cyanidin 3-O-(6''-malonyl-3''-glucosyl-glucoside) were detected in F4; esculin and kaempferide, detected in F5, could be associated with the antibacterial and antioxidant effect.