Bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400, and polyethylene glycol 1000 against selected microorganisms

Reviewing the evidence of antimicrobial activity of glycols

In the 1940s and 1950s, researchers seeking safe and novel ways to eliminate airborne pathogens from enclosed spaces, investigated glycol vapours as a method of disinfection. More recently, the COVID-19 pandemic highlighted the need for a non-toxic aerial disinfectant that can be used in the presence of people. This scoping review is intended to analyse the early and more recent literature on glycol disinfection, scrutinizing the methodologies used, and to determine if the use of glycols as modern-day disinfectants is justified PRISMA-ScR guidelines were used to assess the 749 articles retrieved from the Web of Science platform, with 46 articles retained after the search strategy was applied. Early studies generally demonstrated good disinfection capabilities against airborne bacteria and viruses, particularly with propylene glycol (PG) vapour. Vapour pressure, relative humidity, and glycol concentration were found to be important factors affecting the efficacy of glycol vapours. Contact times depended mainly on the glycol application method (i.e. aerosolization or liquid formulation), although information on how glycol efficacy is impacted by contact time is limited. Triethylene glycol (TEG) is deemed to have low toxicity, carcinogenicity, and mutagenicity and is registered for use in air sanitization and deodorization by the US Environmental Protection Agency. Glycols are also used in liquid formulations for their antimicrobial activity against a wide range of microorganisms, although when used as a non-active excipient in products, their contribution to antimicrobial efficacy is rarely assessed. The appropriate use of liquid glycol-containing formulations was found to positively impact the antimicrobial capabilities of disinfectants when used at temperatures <0, food preservatives, and dental medicaments. Providing modern delivery technology can accurately control environmental conditions, the use of aerosolized glycol formulations should lead to successful disinfection, aiding infection prevention, and control regimens.

Synthesis of castor oil/PEG as textile softener

New castor oil/polyethylene glycol (CAO/PEG) hybrids were synthesized by reacting of CAO with PEG 300, 600, 1000, 2000 or 4000, in presence of ammonium per sulfate (APS) as an initiator. The optimum conditions to synthesis such hybrids are: PEG/CAO weight ratio, 35%; APS/PEG weight ratio, 15%; reaction temperature, 80 °C; and reaction time, 60 min. Only the hybrids based on PEG 1000 and 2000 formed oil in water stable emulsions. Treating cotton fabric samples with easy care finishing formulation containing 40 g/L of the synthesized hybrids emulsions results in an enhancement in softness, tensile strength, whiteness index, and stiffness along with a reduction in nitrogen content, wrinkle recovery angle, and wettability properties of treated fabric, compared to that sample finished in absence of that emulsions. The chemical structure of the synthesized CAO/PEG1000 hybrid was confirmed via the FTIR and 1HNMRanalysis whereas the TEM analysis showed that the particles size of that hybrid emulsion is in the range of 27-105 nm. Moreover, such hybrid emulsion treated fabric surface was characterized via SEM and EDX analysis. Furthermore, treating dyed samples with the nominated hybrid emulsion improves the color strength of that samples but keeps the washing fastness, wet rubbing fastness as well as alkaline perspiration fastness of the dyed/finished samples unchanged. The wet rubbing fastness and alkaline perspiration fastness of all the dyed/finished samples were enhanced while the light fastness of such samples decreased.

What's in My Ink: An Analysis of Commercial Tattoo Ink on the US Market

As tattoos continue to rise in popularity, the demand for tattoo ink has surged. Historically, tattoo inks have been underregulated in the US market. This study analyzes inks from nine different brands that are common in the United States, ranging from major to small manufacturers. Out of 54 inks, 45 contained unlisted additives and/or pigments. Major, unlisted adulterants include poly(ethylene glycol), propylene glycol, and higher alkanes. Many of the adulterants pose possible allergic or other health risks. Taken together, the results from this study highlight the potential for a significant issue around inaccurate tattoo ink labeling in the United States.

Glycols: The ubiquitous solvent for dermal formulations

Glycols stand out as one of the most commonly employed safe and effective excipients for pharmaceutical and cosmeceutical products. Their widespread adoption can be attributed to their exceptional solvency characteristics and their ability to interact effectively with skin lipids and keratin for permeation enhancement. Notably, propylene glycol enjoys significant popularity in this regard. Ongoing research endeavours have been dedicated to scrutinising the impact of glycols on dermal drug delivery and shedding light on the intricate mechanisms by which glycols enhance skin permeation. This review aims to mitigate the discordance within the existing literature, assemble a holistic understanding of the impact of glycols on the percutaneous absorption of active compounds and furnish the reader with a profound comprehension of the foundational facets pertaining to their skin permeation enhancement mechanisms, while simultaneously delving deeper into the intricacies of these processes.

Mathematical modeling of cholera dynamics with intrinsic growth considering constant interventions

A mathematical model that describes the dynamics of bacterium vibrio cholera within a fixed population considering intrinsic bacteria growth, therapeutic treatment, sanitation and vaccination rates is developed. The developed mathematical model is validated against real cholera data. A sensitivity analysis of some of the model parameters is also conducted. The intervention rates are found to be very important parameters in reducing the values of the basic reproduction number. The existence and stability of equilibrium solutions to the mathematical model are also carried out using analytical methods. The effect of some model parameters on the stability of equilibrium solutions, number of infected individuals, number of susceptible individuals and bacteria density is rigorously analyzed. One very important finding of this research work is that keeping the vaccination rate fixed and varying the treatment and sanitation rates provide a rapid decline of infection. The fourth order Runge-Kutta numerical scheme is implemented in MATLAB to generate the numerical solutions.

Propylene glycol inactivates respiratory viruses and prevents airborne transmission

Viruses are vulnerable as they transmit between hosts, and we aimed to exploit this critical window. We found that the ubiquitous, safe, inexpensive and biodegradable small molecule propylene glycol (PG) has robust virucidal activity. Propylene glycol rapidly inactivates a broad range of viruses including influenza A, SARS-CoV-2 and rotavirus and reduces disease burden in mice when administered intranasally at concentrations commonly found in nasal sprays. Most critically, vaporised PG efficiently abolishes influenza A virus and SARS-CoV-2 infectivity within airborne droplets, potently preventing infection at levels well below those tolerated by mammals. We present PG vapour as a first-in-class non-toxic airborne virucide that can prevent transmission of existing and emergent viral pathogens, with clear and immediate implications for public health.

In vitro bactericidal efficacy of a new triple antibiotic paste formulation against Enterococcus faecalis biofilm

The aim of this study was to evaluate the bactericidal efficacy on Enterococcus faecalis biofilm of a novel, low-concentration triple-antibiotic paste (TAP-L2) in propylene glycol/carboxymethylcellulose vehicle (VEH-2), a ready-to-use prototype, compared with two currently used products; a low-concentration (TAP-L1) and a high-concentration paste (TAP-H1) mixed in macrogol/propylene glycol vehicle (VEH-1). Sixty-two root canals were infected with E. faecalis biofilm, medicated with (a) TAP-L1, (b) TAP-L2, (c) TAP-H1, (d) VEH-1 or (e) VEH-2 (n = 10) and incubated for 21 days. Live/dead assays were performed using confocal laser scanning microscopy (CLSM), and dead bacteria (%) were calculated. The TAP-H1 group demonstrated the highest dead bacteria (67.54 ± 2.38%), which was significantly higher than the TAP-L2 and TAP-L1 groups (56.85 ± 7.11% and 54.23 ± 10.19%) (p < 0.05). The TAP groups demonstrated significantly higher dead bacteria than the VEH-1 and VEH-2 groups (47.51 ± 6.41% and 45.14 ± 8.28%) (p < 0.05). The ready-to-use TAP-L2 had antibacterial activity comparable to TAP-L1, both of which were lower than TAP-H1.

Propylene Glycol Potentiates the Inhibitory Action of CTZ Paste on Antibiotic-Resistant Enterococcus faecalis Isolated from the Root Canal: An In Vitro Study

This study aimed to evaluate if the change of vehicle for CTZ (Chloramphenicol, Tetracycline, zinc oxide, and Eugenol) paste improves the inhibition of Enterococcus faecalis in vitro. The vehicles evaluated alone and mixed with CTZ were Eugenol, propylene glycol (PG), super-oxidized solution (SOS), grapefruit-seed extract (GSE), and 0.9% saline solution as a negative control. A clinical isolate of E. faecalis was morphologically and biochemically characterized, and its antimicrobial susceptibility was tested using 20 antimicrobial agents. Once characterized, the clinical isolate was cultivated to perform the Kirby-Bauer disc diffusion method with paper discs embedded with the different vehicles mixed or used alone, and incubated at 37 °C for 24 h. Data were analyzed using one-way ANOVA, and the means were compared using Tukey test with a significance level of p < 0.05. For vehicles used alone, GSE presented the greatest inhibition showing a statistically significant difference with the rest of the vehicles. When vehicles were mixed with the CTZ paste, PG showed a greater inhibition with a statistically significant difference from the rest of the vehicles. In conclusion, the vehicle used to mix the CTZ paste plays an important role in the inhibition of E. faecalis in vitro; therefore, we consider that this can be an important factor to achieve success in the use of this technique.

Effect of Oral Administration of Polyethylene Glycol 400 on Gut Microbiota Composition and Diet-Induced Obesity in Mice

Polyethylene glycol (PEG) is a commonly used dispersant for oral administration of hydrophobic agents. PEG is partly absorbed in the small intestine, and the unabsorbed fraction reaches the large intestine; thus, oral administration of PEG may impact the gut microbial community. However, to the best of our knowledge, no study evaluated the effects of PEG on gut commensal bacteria. Herein, we aimed to determine whether oral administration of PEG modifies the gut microbiota. Administration of PEG400 and PEG4000 altered gut microbial diversity in a concentration-dependent manner. Taxonomic analysis revealed that Akkermansia muciniphila and particularly Parabacteroides goldsteinii were overrepresented in mice administered with 40% PEG. PEG400 administration ameliorated the high-fat diet (HFD)-induced obesity and adipose tissue inflammation. Fecal microbiome transplantation from PEG400-administered donors counteracted the HFD-induced body and epididymal adipose tissue weight gain, indicating that PEG400-associated bacteria are responsible for the anti-obesity effect. Conversely, carboxymethyl cellulose, also used as a dispersant, did not affect the abundance of these two bacterial species or HFD-induced obesity. In conclusion, we demonstrated that oral administration of a high concentration of PEG400 (40%) alters the gut microbiota composition and ameliorates HFD-induced obesity.

Levofloxacin HCl-Loaded Eudragit L-Based Solvent Exchange-Induced In Situ Forming Gel Using Monopropylene Glycol as a Solvent for Periodontitis Treatment

Solvent exchange-induced in situ forming gel (ISG) is currently an appealing dosage form for periodontitis treatment via localized injection into the periodontal pocket. This study aims to apply Eudragit L and Eudragit S as matrix components of ISG by using monopropylene glycol as a solvent for loading levofloxacin HCl for periodontitis treatment. The influence of Eudragit concentration was investigated in terms of apparent viscosity, rheological behavior, injectability, gel-forming behavior, and mechanical properties. Eudragit L-based formulation presented less viscosity, was easier to inject, and could form more gel than Eudragit S-based ISG. Levofloxacin HCl-loading diminished the viscosity of Eudragit L-based formulation but did not significantly change the gel formation ability. Higher polymer loading increased viscosity, force-work of injectability, and hardness. SEM photographs and µCT images revealed their scaffold formation, which had a denser topographic structure and less porosity attained owing to higher polymer loading and less in vitro degradation. By tracking with fluorescence dyes, the interface interaction study revealed crucial information such as solvent movement ability and matrix formation of ISG. They prolonged the drug release for 14 days with fickian drug diffusion kinetics and increased the release amount above the MIC against test microbes. The 1% levofloxacin HCl and 15% Eudragit L dissolved in monopropylene glycol (LLM15) was a promising ISG because of its appropriate viscosity (3674.54 ± 188.03 cP) with Newtonian flow, acceptable gel formation and injectability (21.08 ± 1.38 N), hardness (33.81 ± 2.3 N) and prolonged drug release with efficient antimicrobial activities against S. aureus (ATCC 6538, 6532, and 25923), methicillin-resistant S. aureus (MRSA) (S. aureus ATCC 4430), E. coli ATCC 8739, C. albicans ATCC 10231, P. gingivalis ATCC 33277, and A. actinomycetemcomitans ATCC 29522; thus, it is the potential ISG formulation for periodontitis treatment by localized periodontal pocket injection.

Carbonation inhibitor by polyethylene glycol encapsulation of calcium hydroxide fine particles to improve antimicrobial and root canal penetration properties

The carbonation of calcium hydroxide (Ca(OH)₂) is affected by humidity and a saturated atmosphere. Ca(OH)₂ from nature is easily carbonation and self-aggregates into calcium carbonate (CaCO₃), resulting in larger particle size impairing the antimicrobial properties due to lack of penetration into the dentinal tubules and lower ion dissociation. To reduce the particle size, the wet beads milling process with distilled water as the medium is commonly used, but often results in great carbonation of the final product. Polyethylene Glycol (PEG) may inhibit the carbonation process as well as re-agglomeration. However, it requires intensive drying of the fine Ca(OH)₂ particles. As an alternative, we used ethanol as a medium in the milling process, which is easily dried and compatible with PEG as a surfactant. This study aimed to evaluate PEG 400 as a dispersing agent in ethanol medium in the beads milling process to prevent carbonation of the fine Ca(OH)₂ particles. The following groups were analysed CaP-PEG (Ca(OH)₂-PEG) with ethanol as a medium, CaP-Eth (Ca(OH)₂ with ethanol as a medium), CaP-DW (Ca(OH)₂ with distilled water as a medium), CaPC (Ca(OH)₂-carbonated) as the negative control and CaC (Ca(OH)₂ analytical grade) as the positive control The final particle results were characterized to evaluate the crystal structure, functional groups, and particle size. The corresponding pH and antimicrobial activity against Enterococcus faecalis were assessed at 1, 3, 7, and 14 days. The penetration ability was evaluated by Scanning Electron Microscope. The data obtained were analysed by ANOVA with a significance level of 5%. PEG was able to inhibit carbonation and stabilize pH for up to 14 days, providing increased antimicrobial activity against E. faecalis. PEG also facilitates the ability of fine Ca(OH)₂ particles to penetrate deeper into the dentine tubules by reducing particle size.

Antiviral Effect of Propylene Glycol against Envelope Viruses in Spray and Volatilized Forms

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly contagious and continues to spread worldwide. To avoid the spread of infection, it is important to control its transmission routes. However, as methods to prevent airborne infections are lacking, people are forced to take measures such as keeping distance from others or wearing masks. Here, we evaluate the antiviral activity of propylene glycol (PG), which is safe, odorless, and volatile. PG showed pronounced antiviral activity against the influenza virus (IAV) at concentrations above 55% in the liquid phase. Given its IAV inactivation mechanism, which involves increasing the fluidity of the viral membrane, PG is expected to have a broad effect on enveloped viruses. PG showed antiviral activity against SARS-CoV-2. We also developed a system to evaluate the antiviral effect of PG in spray and volatilized forms. PG was found to be effective against aerosol IAV in both forms; the effective PG concentration against IAV in the vapor phase was 87 ppmv (0.27 mg/L). These results demonstrate that PG is an effective means for viral inactivation in various situations for infection control. This technology is expected to control the spread of current and future infectious diseases capable of causing outbreaks and pandemics.

High-resolution analyses of associations between medications, microbiome, and mortality in cancer patients

Discerning the effect of pharmacological exposures on intestinal bacterial communities in cancer patients is challenging. Here, we deconvoluted the relationship between drug exposures and changes in microbial composition by developing and applying a new computational method, PARADIGM (parameters associated with dynamics of gut microbiota), to a large set of longitudinal fecal microbiome profiles with detailed medication-administration records from patients undergoing allogeneic hematopoietic cell transplantation. We observed that several non-antibiotic drugs, including laxatives, antiemetics, and opioids, are associated with increased Enterococcus relative abundance and decreased alpha diversity. Shotgun metagenomic sequencing further demonstrated subspecies competition, leading to increased dominant-strain genetic convergence during allo-HCT that is significantly associated with antibiotic exposures. We integrated drug-microbiome associations to predict clinical outcomes in two validation cohorts on the basis of drug exposures alone, suggesting that this approach can generate biologically and clinically relevant insights into how pharmacological exposures can perturb or preserve microbiota composition. The application of a computational method called PARADIGM to a large dataset of cancer patients' longitudinal fecal specimens and detailed daily medication records reveals associations between drug exposures and the intestinal microbiota that recapitulate in vitro findings and are also predictive of clinical outcomes.

Conventional tobacco products harbor unique and heterogenous microbiomes

While an increasing number of studies have evaluated tobacco microbiomes, comparative microbiome analyses across diverse tobacco products are non-existent. Moreover, to our knowledge, no previous studies have characterized the metabolically-active (live) fraction of tobacco bacterial communities and compared them across products. To address these knowledge gaps, we compared bacterial communities across four commercial products (cigarettes, little cigars, cigarillos and hookah) and one research cigarette product. After total DNA extraction (n = 414) from all samples, the V3V4 region of the 16S rRNA gene was sequenced on the Illumina HiSeq platform. To identify metabolically-active bacterial communities within these products, we applied a coupled 5-bromo-2'-deoxyuridine labeling and sequencing approach to a subset of samples (n = 56). Each tobacco product was characterized by its signature microbiome, along with a shared microbiome across all tobacco products consisting of Pseudomonas aeruginosa, P. putida, P. alcaligenes, Bacillus subtilis, and Klebsiella pneumoniae. Comparing across products (using Linear discriminant analysis Effect Size (LEfSe)), a significantly higher (p < 0.05) relative abundance of Klebsiella and Acinetobacter was observed in commercial cigarettes, while a higher relative abundance of Pseudomonas and Pantoea was observed in research cigarettes. Methylorubrum and Paenibacillus were higher in hookah, and Brevibacillus, Lactobacillus, Bacillus, Lysinibacillus, and Staphylococcus were higher in little cigars and cigarillos. Across all products, the majority of the metabolically-active bacterial communities belonged to the genus Pseudomonas, followed by several genera within the Firmicutes phylum (Bacillus, Terribacillus, and Oceanobacillus). Identification of some metabolically-active pathogens such as Bacillus cereus and Haemophilus parainfluenzae in commercial products is of concern because of the potential for these microorganisms to be transferred to users' respiratory tracts via mainstream smoke. Future work is warranted to evaluate the potential impact of these tobacco bacterial communities on users' oral and lung microbiomes, which play such an important role on the spectrum from health to disease.

Comparison of the Formulation, Stability and Biological Effects of Hydrophilic Extracts from Black Elder Flowers (Sambucus nigra L.)

Elderflower preparations have long been used to treat colds and flu, but their use is undeservedly reduced, and only dried flower teas, less often ethanolic extracts, can be purchased in pharmacies. In the case of homemade teas, the medicinal plant material is extracted with hot water for a relatively short time, thus only a small part of the active substances is extracted. The industrially produced ethanolic extract is rich in active substances, but its use is limited since ethanol in many countries is undesirable and unsuitable for children and geriatric patients. Therefore, the aim of this work was to produce extracts from elder flowers using water as extractant and a mixture of water + polyethylene glycol (PEG) 20%, to compare their chemical composition and stability, and to study the ability to neutralize reactive oxygen species (ROS) and to sustain the viability of C6 glial cells under oxidative stress conditions. The ethanolic extract was used as a standard. Thus, the extract with PEG contained more than two times higher amount of total phenolics (PC) than the aqueous one, and the stability at 6-8 °C was comparable to the stability of ethanolic extract. All three extracts showed an antioxidant effect in a concentration-dependent manner in vitro. However, only the PEG containing extract (at 20-40 µg/mL PC) was the most effective in reducing the intracellular level of ROS and sustaining the viability of glial cells. The results suggest that the co-solvent PEG increases the yield of phenolics in the extract, prolongs the stability, and enhances positive biological effects.

Seed Endophytic Achromobacter sp. F23KW as a Promising Growth Promoter and Biocontrol of Rhizoctonia Root Rot of Fenugreek

Root rot is one of the most significant soil and seed-borne fungal diseases, limiting the cultivation of fenugreek plants. Endophytic bacteria and their natural bioproducts have emerged as growth promoters and disease suppressors in the current era. Despite limited research, seeds are a good funder of endophytic microbiomes, which are transmitted from them to other seedling parts, thereby providing a shield against biotic and abiotic anxiety and promoting the growth at early germination and later stages. The current study evaluated the hypothesis that seed endophytic bacteria and their lytic enzymes, growth promotors, and antifungal molecules can induce growth, and inhibit root rot disease development at the same time. The isolation trial from fenugreek seeds revealed a lytic Achromobacter sp., which produces indole acetic acid, has antifungal compounds (e.g., 2-Butanol, 3,3’-oxybis-), and reduces the growth of Rhizoctonia solani by 43.75%. Under the greenhouse and natural field conditions, bacterial cells and/or supernatant improved the growth, physiology, and yield performance of fenugreek plants, and effectively suppressed the progress of root rot disease; this is the first extensive study that uses a new seed-borne endophytic bacterium as a plant-growth-promoting, and biocontrol tool against the sclerotia-forming; R. solani; the causative of fenugreek root rot.

Small Diameter Cell-Free Tissue-Engineered Vascular Grafts: Biomaterials and Manufacture Techniques to Reach Suitable Mechanical Properties

Vascular grafts (VGs) are medical devices intended to replace the function of a blood vessel. Available VGs in the market present low patency rates for small diameter applications setting the VG failure. This event arises from the inadequate response of the cells interacting with the biomaterial in the context of operative conditions generating chronic inflammation and a lack of regenerative signals where stenosis or aneurysms can occur. Tissue Engineered Vascular grafts (TEVGs) aim to induce the regeneration of the native vessel to overcome these limitations. Besides the biochemical stimuli, the biomaterial and the particular micro and macrostructure of the graft will determine the specific behavior under pulsatile pressure. The TEVG must support blood flow withstanding the exerted pressure, allowing the proper compliance required for the biomechanical stimulation needed for regeneration. Although the international standards outline the specific requirements to evaluate vascular grafts, the challenge remains in choosing the proper biomaterial and manufacturing TEVGs with good quality features to perform satisfactorily. In this review, we aim to recognize the best strategies to reach suitable mechanical properties in cell-free TEVGs according to the reported success of different approaches in clinical trials and pre-clinical trials.

Development of Pediatric Dosage Preparation for CVD 103-HgR Live Oral Cholera Vaccine

PXVX0200 is an oral cholera vaccine that is approved for use by the U.S. Food and Drug Administration and European Medicines Agency under the tradename Vaxchora. The vaccine is supplied as two packets, one containing buffer component and the other the active component, that are mixed with water and ingested. The aim of this study was to develop vaccine preparation methods that are appropriate for administering PXVX0200 to children. Developing oral liquid medication for children has unique challenges, including administration volume and palatability. These challenges were addressed by preparing PXVX0200 in different volumes and testing the potency of the vaccine in the presence of sweeteners, flavorings, and food and drinks. Vaccine potency, defined as colony-forming units/dose, was used to determine the compatibility of PXVX0200 with different vaccine preparation methods. We found that the reconstitution volume can be reduced from 100 to 50 mL to accommodate children aged 2 to 6 years and to 10 mL for children aged 6 months to 2 years, as long as the buffer concentration is the same as for the approved (100 mL) dose. Sucrose or stevia sweeteners may also be added without affecting the vaccine potency. Reconstitution in juices or foods was challenging because of effervescence caused by bicarbonate in the buffer component. An alternate preparation method was developed for reconstitution in baby formula. Vaccine preparation methods to make PXVX0200 appropriate for pediatric administration will facilitate administration of the vaccine to improve compliance and protect children from cholera infection while traveling.

Oleaginous yeast Rhodotorula toruloides biomass effect on the metabolism of Arctic char (Salvelinus alpinus)

Sustainability issues arise when using fish oil and vegetable oils in fish feed production for aquaculture purposes. Microbial production of single cell oil is a potential alternative as a lipid ingredient in the production of fish feed. In this study, we replaced the vegetable oils with the oleaginous yeast R. toruloides biomass in the diet of Arctic char (S. alpinus) and investigated the effects on health and composition. Measurement of fish growth parameters showed a higher liver weight and hepatosomatic index in the experimental group of fish fed partly with yeast biomass compared to a control group fed a diet with vegetable oils. No significant differences in the lipid content of muscle and liver tissues were found. The fatty acid profiles in the muscle of both fish groups were similar while the experimental fish group had a higher amount of monounsaturated fatty acids in the liver. Histology of livers showed no significant difference in the number of lipid droplets. The size of hepatic lipid droplets seemed to be related to liver fat content. Quantification of metabolites in the liver revealed no differences between the fish groups while plasma metabolites involved in energy pathways such as alanine, 3-hydroxybutyrate, creatinine, serine, betaine, and choline were significantly higher in the experimental fish group.

Efficacy of chitosan paste as intracanal medication against Enterococcus faecalis and Candida albicans biofilm compared with calcium hydroxide in an in vitro root canal infection model

Background

Enterococcus faecalis and Candida albicans are frequently found in persistent endodontic infection and could remain in dentinal tubules despite intracanal medication with calcium hydroxide (Ca(OH)₂), a commonly used medication. Thus, an effective and safe antimicrobial medication against such refractory infection is necessary in endodontic retreatment, so we aimed to test the efficacy of chitosan paste against these microorganisms compared with Ca(OH)₂ in root canals of extracted human teeth.

Methods

Thirty-six sterilized human root samples prepared from extracted premolars and upper maxillary incisors were infected with E. faecalis for 14 days, while 32 were infected with C. albicans for 48 h, for mature biofilm formation. The samples were assigned to 6 groups of intracanal medications: Group 1: no medication (negative control); Group 2: 20% Polyethylene glycol (PEG); Group 3: 20% Propylene glycol (PG); Group 4: Ca(OH)₂; Group 5: Chitosan + PEG; and Group 6: Chitosan + PG. After 7 days, intracanal surface dentin was harvested using Protaper next, resuspended, serially diluted and spread on Brain–Heart-Infusion agar (for E. faecalis) and Yeast Extract-Peptone-Dextrose agar (for C. albicans) for colony count. Antimicrobial efficacy was determined as percentage of remaining colony forming unit (CFUs) relative to negative control and analyzed using One-way ANOVA and post-hoc Games-Howell test. The significance level was set at 0.05.

Results

For E. faecalis, chitosan + PG had significantly higher antibacterial activity than Ca(OH)₂ (P = 0.039). Chitosan + PEG and chitosan + PG medication significantly reduced viable bacteria compared with negative control, PEG and PG (P = 0.001, 0.003, 0.024, respectively for chitosan + PEG; P = 0.002, 0.003, 0.014, respectively for chitosan + PG). For C.albicans, chitosan + PEG and chitosan + PG were not significantly different from Ca(OH)₂. However, Chitosan + PEG and chitosan + PG, but not Ca(OH)₂, showed a significantly lower level of remaining CFUs compared with negative control (P = 0.013 and 0.005, respectively).

Conclusion

Chitosan paste showed better efficacy in reducing viable E. faecalis biofilm when compared to Ca(OH)₂ after 7-day intracanal medication in this in vitro root canal model. It could also significantly reduce viable C. albicans, but was not significantly different from Ca(OH)₂.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02385-x.

Mucoadhesive and Antimicrobial Allantoin/β Cyclodextrins-Loaded Carbopol Gels as Scaffolds for Regenerative Medicine

Allantoin and its β-cyclodextrin and hydroxypropyl-β-cyclodextrin inclusion complexes 1:1 have been used to prepare carbopol-based mucoadhesive gels. The gelation process occurred by adjustment with glycerol 10% in the presence of triethanolamine. The structural features induced by the presence of allantoin and the corresponding β-cyclodextrins inclusion complexes have been first investigated by infrared spectroscopy highlighting strong interactions within the gels network and ideal crosslinks for the self-healing behavior. The hydrophilicity of the gels was investigated by the determination of the surface tension parameters and the free energy of hydration. The interfacial free energy values indicated prolonged biocompatibility with blood. The gels-water molecule interactions in terms of sorption, permeability, and diffusion coefficients were evaluated by dynamic vapor sorption analysis. The self-assembly process through intermolecular H-bonding, the high hydrophilicity, the mechanical performance, the hydrolytic stability in simulated biological media, the biocompatibility with normal human dermal fibroblast (NHDF) cells, the mucoadhesivity and antimicrobial activity on selected microorganism species (S. Aureus and C. albicans) of the allantoin-based gels recommend them as promising scaffold alternatives in regenerative medicine.

Physico-chemical and nutraceutical properties of Cola lepidota seed oil

The extraction and preliminary characterization of oil from Cola lepidota seed were studied in this paper. The extraction was done in a Soxhlet extractor with n-Hexane as the solvent. The iodine value, acid value, saponification value, and peroxide value of the oil were all measured quantitatively. The oil yielded 1.10 percent, with an iodine value of 57.67 ± 0.01 mg/100 g, an acid value of 15.50 ± 0.01 mg/KOH/g, a saponification value of 125.69 ± 0.15 mg/KOH/g, and a peroxide value of 5.04 ± 0.06 meq/kg/L. GC-MS was used to identify phytochemicals such as hydrouracil, 1,2-propanediol, glycerine, divinyl sulphide, glucitol, and benzoic acid. The findings of this study revealed that the oil has phytochemicals and nutraceutical qualities, indicating that it might be screened and employed in supplementing human and animal diets, as well as in the production of cosmetics and detergents.

E-Cigarette Aerosol Exposure Favors the Growth and Colonization of Oral Streptococcus mutans Compared to Commensal Streptococci

E-cigarettes (e-cigs) have drastically increased in popularity during the last decade, especially among teenagers. While recent studies have started to explore the effect of e-cigs in the oral cavity, little is known about their effects on the oral microbiota and how they could affect oral health and potentially lead to disease, including periodontitis and head and neck cancers. To explore the impact of e-cigs on oral bacteria, we selected members of the genus Streptococcus, which are abundant in the oral cavity. We exposed the commensals Streptococcus sanguinis and Streptococcus gordonii and the opportunistic pathogen Streptococcus mutans, best known for causing dental caries, to e-liquids and e-cig aerosols with and without nicotine and with and without menthol flavoring and measured changes in growth patterns and biofilm formation. Our results demonstrate that e-cig aerosols hindered the growth of S. sanguinis and S. gordonii, while they did not affect the growth of S. mutans. We also show that e-cig aerosols significantly increased biofilm formation by S. mutans but did not affect the biofilm formation of the two commensals. We found that S. mutans exhibits higher hydrophobicity and coaggregation abilities along with higher attachment to OKF6 cells than S. sanguinis and S. gordonii. Therefore, our data suggest that e-cig aerosols have the potential to dysregulate oral bacterial homeostasis by suppressing the growth of commensals while enhancing the biofilm formation of the opportunistic pathogen S. mutans. This study highlights the importance of understanding the consequences of e-cig aerosol exposure on selected commensals and pathogenic species. Future studies modeling more complex communities will provide more insight into how e-cig aerosols and vaping affect the oral microbiota. IMPORTANCE Our study shows that e-cigarette aerosol exposure of selected bacteria known to be residents of the oral cavity hinders the growth of two streptococcal commensals while enhancing biofilm formation, hydrophobicity, and attachment for the pathogen S. mutans. These results indicate that e-cigarette vaping could open a niche for opportunistic bacteria such as S. mutans to colonize the oral cavity and affect oral health.

E-Cigarette Aerosols Promote Oral S. aureus Colonization by Delaying an Immune Response and Bacterial Clearing

E-cigarette (e-cig) vapor has been shown to play a pathological role in oral health and alter the oral microbiota, providing growth advantages for opportunistic pathogens. Enrichment of Staphylococcus aureus, a commensal resident in the oral cavity, correlates with the progression of periodontal disease, suggesting a role as an opportunistic pathogen. Environmental conditions, such as cigarette smoke, are known to increase S. aureus virulence, yet the role of S. aureus in periodontitis and oral preneoplasia is unknown. We exposed oral epithelial cells to e-cig aerosols and showed a dose-dependent cell viability reduction, regardless of nicotine content, in a possible attempt to repair DNA damage, as measured by pH2AX. S. aureus attachment to oral epithelial cells and bacterial biofilm formation were enhanced upon e-cig exposure, indicating an increased capacity for oral colonization. Mechanistically, e-cig aerosol exposure resulted in an immunosuppression, as determined by a reduction in IL8, IL6, and IL1β secretion by oral epithelial cells during co-culture with S. aureus. Consistent with this, e-cig vape reduced the oral epithelial cell clearance of S. aureus. Furthermore, we observed an increased expression of the inflammatory regulator COX2. This work suggests that e-cigs promote S. aureus colonization and modulate the oral inflammatory response, possibly promoting oral periodontitis and preneoplasia.

Antibacterial and Chemical Characterization of Silica-Quercetin-PEG Hybrid Materials Synthesized by Sol-Gel Route

This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus).

Antibacterial efficacy, calcium ion release, and pH using calcium hydroxide with three vehicles

Context

Vehicles combined with calcium hydroxide, as an intracanal medicament, play a key factor in affecting antibacterial, calcium release, and pH.

Aims

The aim of this study is to investigate the effect of three vehicles (glycerin, chlorhexidine gluconate/CHX, and chitosan nanoparticle) combined with calcium hydroxide as an intracanal medicament on antibacterial efficacy against Enterococcus faecalis, calcium ion release, and pH of at different interval times of 7 and 14 days.

Settings and Design

The research was experimental laboratory.

Materials and Methods

Each study used 24 samples of eight teeth each and was randomly divided into three groups based on the vehicle of calcium hydroxide: group 1: glycerin, group 2: CHX, and group 3: chitosan nanoparticles. Each vehicle group was then further divided into two subgroups of four teeth based on the interval times (group A: 7 days and group B: 14 days). The antibacterial efficacy was determined using an agar diffusion method. Calcium ion release was analyzed with atomic absorption spectrometry, and pH was measured using a pH meter.

Statistical Analysis Used

Data from each study were analyzed by two-way ANOVA, followed by Tukey's test with a significance level of 95%.

Results

The results exhibited that chitosan nanoparticles had the highest antibacterial efficacy against E. faecalis, calcium ion release, and pH, while the lowest was glycerin at 7 and 14 days (P < 0.05).

Conclusion

Calcium hydroxide combined with chitosan nanoparticle as an intracanal medicament produced the highest antibacterial efficacy against E. faecalis, calcium ion release, and pH than glycerin and CHX at intervals of 7 and 14 days.

Liquid Chromatography-Nanoelectrospray Ionization-High-Resolution Tandem Mass Spectrometry Analysis of Apurinic/Apyrimidinic Sites in Oral Cell DNA of Cigarette Smokers, e-Cigarette Users, and Nonsmokers

Cigarette smoking is an established risk factor for oral cancer. The health effects of e-cigarettes are still under investigation but may disturb oral cavity homeostasis and cause lung and cardiovascular diseases. Carcinogens and toxicants in tobacco products and e-cigarettes may damage DNA, resulting in the formation of apurinic/apyrimidinic (AP) sites and initiation of the carcinogenic process. In this study, we optimized a liquid chromatography-nanoelectrospray ionization-high-resolution tandem mass spectrometry method to analyze AP sites in buccal cell DNA of 35 nonsmokers, 30 smokers, and 30 e-cigarette users. AP sites in e-cigarette users (median 3.3 per 10⁷ nts) were significantly lower than in smokers (median 5.7 per 10⁷ nts) and nonsmokers (median 6.0 per 10⁷ nts). AP sites in smokers were not significantly different from nonsmokers (p > 0.05). The e-cigarette vaporizing solvents propylene glycol and glycerin were tested and did not protect against AP site formation in in vitro control and carcinogen exposed rat liver homogenates. However, propylene glycol may inhibit bacteria in oral cells, resulting in reduced inflammation and related effects, and reduced AP site levels in e-cigarette user DNA. This is the first study to examine AP site formation in e-cigarette users and to evaluate AP sites in human oral cell DNA.

The inhibitory effect of a novel neem paste against cariogenic bacteria

Background

Dental caries is a major oral health problem, which associates with cariogenic bacteria. Streptococcus mutans and Lactobacillus acidophilus are facultative anaerobic bacteria that are found in tooth decay. Accordingly, neem leaf extract was developed due to its great anti-microbial property against many bacteria. The aim of this study was to determine anti-cariogenic properties of neem leaf extract in a novel paste preparation.

Material and Methods

The neem extract was derived from maceration of dry neem leaves in ethanol for 48 h. The ethanolic extract was subjected to chemical identification using GC-MS. Neem pastes were prepared from ethanolic extract mixed with polyethylene glycol paste with or without zinc oxide. S. mutans and L. acidophilus test were initiated at bacterial concentration of 108 CFU/ml. The antibacterial activity was then performed by disc diffusion method following by minimum bactericidal concentration (MBC) technique.

Results

GC-MS result displayed 35 compounds. Compounds found in the extract were n-Hexadecanoic acid (31.18%), Hentriacontane (18%), Phytol (16.79%). Disc diffusion showed that ethanolic extract and neem pastes inhibited growth of both bacteria. For MBC, neem paste with zinc oxide at concentration of neem 0.4 mg/ml was the most effective concentration on inhibiting S. mutans growth. Neem pastes and ethanolic extract at concentration of neem 6.25 mg/ml inhibited L. acidophilus growth.

Conclusions

The ethanolic neem leaf extract and novel neem pastes had antimicrobial effect on both S. mutans and L. acidophilus. By this property, neem paste could be developed for the application in dental field, i.e. pulp capping.

Key words:Neem, Azadirachta indica, antimicrobial, cariogenic bacteria.

Assessment of the safety and anti-inflammatory effects of three Bacillus strains in the respiratory tract

Chronic respiratory diseases are part of accumulating health problems partly due to worldwide increase in air pollution. By their antimicrobial and immunomodulatory properties, some probiotics constitute promising alternatives for the prevention and treatment of chronic respiratory diseases. We have isolated Bacillus strains from Korean fermented foods and selected three potentially probiotic strains (two Bacillus subtilis and one Bacillus amyloliquefaciens) based on safety, antimicrobial efficacy, activity against airborne pathogens and their immunomodulatory properties in vivo. Safety evaluation included in silico analysis for confirming absence of virulence genes. Safety for the respiratory tract was confirmed by an in vivo pathogenicity test using a murine model. Antimicrobial activity was displayed against several airborne pathogens. Potential antimicrobial metabolites such as 2,3-butanediol and propylene glycol were identified as possible antagonistic agents. Immunomodulatory properties in vitro were confirmed by upregulation of IL-10 expression in a macrophage cell line. Intranasal instillation and inhalation in an ovalbumin (OVA)-induced lung inflammation murine model reduced T helper type 2 (Th2) cytokines at transcriptional and protein levels in the lungs. The safety and potentially beneficial role of these Bacillus strains could be demonstrated for the respiratory tract of a murine model.

In vitro amoebicidal effects of arabinogalactan-based ophthalmic solution

The main corneal infections reported worldwide are caused by bacteria and viruses but, recently, the number of Acanthamoeba keratitis (AK) cases has increased. Acanthamoeba genus is an opportunistic free living protozoa widely distributed in environmental and clinical sources, with two life-cycle stages: the trophozoite and the cyst. AK presents as primary symptoms eye redness, epithelial defects, photophobia and intense pain. An early diagnosis and an effective treatment are crucial to avoid blindness or eye removal but, so far, there is no established treatment to this corneal infection. Diverse research studies have reported the efficacy of commercialized eye drops and ophthalmic solutions against the two life cycle stages of Acanthamoeba strains, that usually present preservatives such as Propylene Glycol of Benzalkonium chloride (BAK). These compounds present toxic effects in corneal cells, favouring the inflammatory response in the so sensitive eye tissue. In the present work we have evaluated the efficacy of nine proprietary ophthalmic solutions with and without preservatives (ASDA Dry Eyes Eyedrops, Miren®, ODM5®, Ectodol®, Systane® Complete, Ocudox®, Matrix Ocular®, Alins® and Coqun®) against the two life cycle stages of three Acanthamoeba strains. Our work has demonstrated the high anti-Acanthamoeba activity of Matrix Ocular®, which induces the programmed cell death mechanisms in Acanthamoeba spp. trophozoites. The high efficacy and the absence of ocular toxic effects of Matrix Ocular®, evidences the use of the Arabinogalactan derivatives as a new source of anti-AK compounds.

Fabrication and in vitro evaluation of thermally cross-linked gelatin nanofibers for drug delivery applications

In this study, four different nanofibers consisting of gelatin (Gel), doxorubicin (DOX) with gel (DOX@Gel), a composite of gel with poly(ethylene glycol) (PEGylated-gel), and DOX@PEGylated-gel were fabricated. Subsequently, the nanofibers were thermally cross-linked in order to offer a stable and biocompatible alternative for the biological applications of nanofibers such as drug delivery and tissue engineering. Nanofibers were characterized by scanning electron microscopy, Fourier Transform-Infrared Spectroscopy (FT-IR), and confocal microscopy. The formation of smooth, continuous, and uniform nanofibers was observed and the addition of PEG resulted in an increase whereas the incorporation of DOX into nanofibers had no significant change in the diameter of nanofibers. Crosslinking also enlarged the diameter of all nanofibers and the most dramatic increase was observed 53% by DOX@PEGylated-gel. Afterward, the biological performance of the nanofibers was investigated by drug release profile, cytotoxicity on A549 cell line as well as antimicrobial activity with E. coli and S. aureus. The results indicate an enhanced drug release profile, moderate antimicrobial activity, and reasonable cytotoxic efficiency for thermally cross-linked nanofibers compared to uncross-linked nanofibers.

Alcohol-Based Hand Sanitizers in COVID-19 Prevention: A Multidimensional Perspective

The global use of alcohol-based hand sanitizers (ABHS) as an important means of controlling the transmission of infectious disease has increased significantly as governments and public health agencies across the world advocated hand hygiene as a preventative measure during the COVID-19 pandemic. Although the performance of these products is most commonly defined as a function of their alcohol concentration, they are multifaceted products in which an interplay of several factors is important in determining efficacy. This paper discusses the interplay between ABHS input (formulation) factors and output (product performance) factors in the context of a multidimensional perspective using a novel representative paradigm. In the model, represented in the form of a three-dimensional tetrahedron, each of the faces represents inputs in the manufacturing of the ABHS product, which are the type and amount of alcohol, the inactive ingredients, the formulation and the manufacturing practices. The four corners of the tetrahedron represent the product performance factors which include product efficacy, sensory characteristics, usage and compliance and product safety. The multidimensional approach to the formulation and evaluation of ABHS shows that several factors contribute to the effectiveness and utility of these products. The paradigm provides a useful framework for manufacturers of ABHS and related healthcare products.

Grapefruit Seed Extract as a Natural Derived Antibacterial Substance against Multidrug-Resistant Bacteria

Multidrug-resistant (MDR) bacteria are increasing due to the abuse and misuse of antibiotics, and nosocomial infections by MDR bacteria are also increasing. The aim of this study was to identify new substances that can target MDR bacteria among 12 plant extracts that are known to have antibacterial effects. The experiments were performed by the disk diffusion test and microdilution minimum inhibitory concentration (MIC) test, as described by the Clinical and Laboratory Standards Institute (CLSI). By screening against methicillin-sensitive Staphylococcus aureus (MSSA), grapefruit seed extract (GSE) was selected from 12 plant extracts for subsequent experiments. GSE showed antibacterial effects against methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) in the disk diffusion test. Even at the lowest concentration, GSE showed antibacterial activity in the microdilution MIC test. As a result, we can conclude that GSE is a naturally derived antibacterial substance that exhibits a favorable antibacterial effect even at a very low concentration, so it is a good candidate for a natural substance that can be used to prevent or reduce nosocomial infections as coating for materials used in medical contexts or by mixing a small amount with other materials.

Synergistic Antimicrobial Activity of Supplemented Medical-Grade Honey against Pseudomonas aeruginosa Biofilm Formation and Eradication

Biofilms hinder wound healing. Medical-grade honey (MGH) is a promising therapy because of its broad-spectrum antimicrobial activity and the lack of risk for resistance. This study investigated the inhibitory and eradicative activity against multidrug-resistant Pseudomonas aeruginosa biofilms by different established MGH-based wound care formulations. Six different natural wound care products (Medihoney, Revamil, Mebo, Melladerm, L-Mesitran Ointment, and L-Mesitran Soft) were tested in vitro. Most of them contain MGH only, whereas some were supplemented. L-Mesitran Soft demonstrated the most potent antimicrobial activity (6.08-log inhibition and 3.18-log eradication). Other formulations ranged between 0.89-log and 4.80-log inhibition and 0.65-log and 1.66-log eradication. Therefore, the contribution of different ingredients of L-Mesitran Soft was investigated in more detail. The activity of the same batch of raw MGH (1.38-log inhibition and 2.35-log eradication), vitamins C and E (0.95-log inhibition and 0.94-log eradication), and all ingredients except MGH (1.69-log inhibition and 0.75-log eradication) clearly support a synergistic activity of components within the L-Mesitran Soft formulation. Several presented clinical cases illustrate its clinical antimicrobial efficacy against Pseudomonas aeruginosa biofilms. In conclusion, MGH is a potent treatment for Pseudomonas biofilms. L-Mesitran Soft has the strongest antimicrobial activity, which is likely due to the synergistic activity mediated by its supplements.

Al-Jenoobi F, A. Alzahrani K, H. Al-Agamy M, M. Al-Mohizea A. Investigating Non-Therapeutic Pharmaceutical Substances for Improving In-Vitro Efficacy of Clindamycin Phosphate Against MRSA and Staphylococcus Epidermidis

The aim of present study was to investigate the effect of pharmaceutical excipients and other active substances on antimicrobial efficacy of standard antibiotic against resistant and susceptible microorganisms. Pharmaceutical excipients (sodium lauryl sulfate [SLS], Tween-80, citric acid, NaOH, NaCl) and active substances (fusidic acid, sorbic acid) were investigated to check in-vitro efficacy and their effect on the efficacy of standard antibiotic. Clindamycin was selected as standard antibiotic. Clindamycin was found to be ineffective against methicillin-resistant Staphylococcus aureus (MRSA). Fusidic acid and SLS showed concentration dependent effect against MRSA. Other tested substances were also ineffective against MRSA, and also failed to improve the susceptibility of MRSA towards clindamycin. The clindamycin + fusidic acid (0.05 µg, 0.1 µg), and clindamycin + SLS (0.5 mg, 1 mg) showed concentration dependent effect on Staphylococcus epidermidis (S. epidermidis). Clindamycin combinations with fusidic acid or SLS showed better inhibition of S. epidermidis, than individual substance. At lower concentration of clindamycin (2 µg), the sorbic acid (25 µg) improves its effectiveness. SLS (0.5 mg, 1 mg) and clindamycin (4 µg, 10 µg) showed almost equal zone of inhibition against S. epidermidis, respectively. Present findings showed that certain pharmaceutical excipients (e.g. SLS) are effective against resistant and susceptible microbes, and suggested that more excipients should be screened for their antimicrobial potential and their ability to improve the efficacy of standard antibiotics.

Effects of Polyethyelene Glycol-Desferrioxamine:Gallium Conjugates on Pseudomonas aeruginosa Outer Membrane Permeability and Vancomycin Potentiation

Pseudomonas aeruginosa exhibits a broad spectrum of intrinsic antibiotic resistance because of the limited permeability of its outer membrane. Given this situation, molecules that could make Gram-negative bacteria more permeable and more susceptible to large-scaffold Gram-positive antibiotics may be advantageous. Herein, we evaluate the antimicrobial activity of a series of targeted poly(ethylene glycol)-desferrioxamine/gallium (PEG-DG) conjugates that can improve the sensitivity of P. aeruginosa to the glycopeptide vancomycin (VAN). We observed that single-ended mPEG-DG and double-ended PEG-DG₂ conjugates characterized by PEG MW ≥2000 synergistically enhanced the sensitivity of VAN against P. aeruginosa reference strains PAO1 and ATCC 27853 and three clinically isolated carbapenem-resistant strains, but not Escherichia coli strain ATCC 25922. Although the exact mechanism of this phenomenon is currently under investigation, PEG-DG conjugates enhanced nitrocefin (NCF), hexidium iodide (HI), and VAN permeability only when PEG and DG were directly conjugated. The two most important physicochemical factors contributing to the synergistic activity observed with VAN relate to (1) the final concentration of DG ligands conjugated to the polymer and (2) the polymer length, wherein MW ≥2000 yielded a similar fractional inhibitory concentration.

Chemical Profile and Antimicrobial Activity of the Fungus-Growing Termite Strain Macrotermes Bellicosus Used in Traditional Medicine in the Republic of Benin

The fungus growing termite species Macrotermes bellicosus (M. bellicosus) is used in nutrition and traditional medicine in the Republic of Benin for the treatment of infectious and inflammatory diseases. Previous findings demonstrated evidence of anti-inflammatory and spasmolytic properties of M. bellicosus. The aim of the present study was to evaluate the antimicrobial potential of different extracts of M. bellicosus samples and determine the chemical profile of an ethanolic M. bellicosus extract. Chemical profiling was conducted using centrifugal partition chromatography and ¹³C-NMR, followed by MALDI-TOF MS. Major identified compounds include hydroquinone (HQ), methylhydroquinone (MHQ), 3,4-dihydroxyphenethyl glycol (DHPG), N-acetyldopamine (NADA) and niacinamide. The fatty acid mixture of the extract was mainly composed of linoleic and oleic acid and highlights the nutritional purpose of M. bellicosus. Using the Kirby–Bauer disc diffusion and broth microdilution assay, an antibacterial activity of M. bellicosus samples was observed against various clinical strains with a highest growth inhibition of S. aureus. In addition, HQ and MHQ as well as fractions containing DHPG, niacinamide and NADA inhibited S. aureus growth. The reported antimicrobial activity of M. bellicosus and identified active substances provide a rationale for the traditional medicinal use of M. bellicosus.

Electrospun Nanodiamond-Silk Fibroin Membranes: A Multifunctional Platform for Biosensing and Wound-Healing Applications

Next generation wound care technology capable of diagnosing wound parameters, promoting healthy cell growth, and reducing pathogenic infections noninvasively would provide patients with an improved standard of care and accelerated wound repair. Temperature is one of the indicating biomarkers specific to chronic wounds. This work reports a hybrid, multifunctional optical material platform-nanodiamond (ND)-silk membranes as biopolymer dressings capable of temperature sensing and promoting wound healing. The hybrid structure was fabricated through electrospinning, and 3D submicron fibrous membranes with high porosity were formed. Silk fibers are capable of compensating for the lack of an extracellular matrix at the wound site, supporting the wound-healing process. Negatively charged nitrogen vacancy (NV^-) color centers in NDs exhibit optically detected magnetic resonance (ODMR) and act as nanoscale thermometers. This can be exploited to sense temperature variations associated with the presence of infection or inflammation in a wound, without physically removing the dressing. Our results show that the presence of NDs in the hybrid ND-silk membranes improves the thermal stability of silk fibers. NV^- color centers in NDs embedded in silk fibers exhibit well-retained fluorescence and ODMR. Using the NV^- centers as fluorescent nanoscale thermometers, we achieved temperature sensing in 25-50 °C, including the biologically relevant temperature window, for cell-grown ND-silk membranes. An enhancement (∼1.5× on average) in the temperature sensitivity of the NV^- centers was observed for the hybrid materials. The hybrid membranes were further tested in vivo in a murine wound-healing model and demonstrated biocompatibility and equivalent wound closure rates as the control wounds. Additionally, the hybrid ND-silk membranes exhibited selective antifouling and biocidal propensity toward Gram-negative Pseudomonas aeruginosa and Escherichia coli, while no effect was observed on Gram-positive Staphylococcus aureus.

Interaction between Lactobacillus reuteri and periodontopathogenic bacteria using in vitro and in vivo (G. mellonella) approaches

Periodontitis is a multifactorial inflammatory disease, and the major cause of tooth loss in adults. New therapies have been proposed for its treatment, including the use of probiotics such as Lactobacillus reuteri. The objective of this study was to evaluate the antimicrobial effects of L. reuteri: live, heat-killed and culture filtrate (cell-free supernatant), on periodontopathogenic bacteria (Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans) in vitro, as well as the in vivo survival curve, hemocyte density and microbial recovery using Galleria mellonella. For in vitro assays, all preparations reduced colony forming units of F. nucleatum, while only live L. reuteri reduced the growth of A. actinomycetemcomitans. All treatments reduced periodontopathogenic bacteria growth in vivo. The treatment with the supernatant increased the survival of larvae infected with F. nucleatum more than the treatment with live L. reuteri, and none of the treatments altered the survival of A. actinomycetemcomitans-infected larvae. In addition, the treatment with L. reuteri preparations did not alter the hemocyte count of F. nucleatum- and A. actinomycetemcomitans-infected larvae. This study demonstrated that L. reuteri preparations exerted antimicrobial effects and increased the survival of G. mellonella infected by F. nucleatum, although only live L. reuteri was able to reduce the growth of A. actinomycetemcomitans in vitro.

Evaluation of the Bactericidal Activity of a Hyaluronic Acid-Vehicled Clarithromycin Antibiotic Mixture by Confocal Laser Scanning Microscopy

Confocal laser scanning microscopy (CLSM) was used to evaluate the antibacterial effect and depth of action of a novel clarithromycin-containing triple antibiotic mixture, which was proposed for root canal disinfection in dental pulp regeneration. A previous study reported that this mixture had no tooth discoloration effects in vitro. After infection with Enterococcus faecalis for 3 weeks, the dentinal tubules in the cylindrical root specimens were exposed to different antibiotic mixtures: ciprofloxacin, metronidazole and minocycline (3-MIX); ciprofloxacin, metronidazole and clarithromycin (3-MIXC) and ciprofloxacin and metronidazole (2-MIX). Each antibiotic formulation was mixed with macrogol (MG) or hyaluronic acid (HA) vehicles. CLSM and viability staining were used to quantitatively analyze the mean depth of the antibacterial effect and the proportions of dead and live bacteria inside the dentinal tubules. The 3-MIX and 3-MIXC demonstrated a similar depth of action. The mean proportion of dead bacteria was similar in the 3-MIX and 3-MIXC groups, and both were statistically higher than that of 2-MIX (p = 0.014). Each antibiotic mixture showed a higher bactericidal efficacy if conveyed with HA, compared to MG (3-MIX, p = 0.019; 3-MIXC, p = 0.013 and 2-MIX, p = 0.0125). The depth of action and the antibacterial efficacy of 3-MIXC seemed comparable with 3-MIX.