Active Antimicrobial Component Research Articles

Smart elastomer sanitizer with chemically bonded active compound and on‐demand‐release antimicrobial functionalities

AbstractHand or surface sanitizers are all liquid‐based products which can be mainly categorized as alcohol or non‐alcohol based. The constant release of highly persistent disinfectants and chemicals is hazardous to the environment and human health. Herein, a new concept of solid elastomer sanitizer with inherent fast‐killing antimicrobial property is described. Silicone (PDMS) was chosen as the elastomer where the active antimicrobial component of imidazolium polymer (PIM) was carefully modified and incorporated into the PDMS matrix through strong covalent bonds. This chemically bonded antimicrobial component within PDMS acts via release‐on‐demand model which allows for the long‐term reusability of the material. The resulting material can serve as a reusable solid sanitizer that is toxic‐free and skin‐friendly with fast‐killing property. It was proven to sanitize our hands or surfaces and kill microbes within 30–60 s of contact, including ESKAPE pathogens, bacteria, fungi and MS2 bacteriophage. This new concept of solid sanitizer methodology will provide an interesting insight and infinite possibilities for extending to other types of elastomers with suitable or tunable antimicrobial components. This also helps to provide a safer and greener sanitizing model which can dramatically reduce the usage and/or release of disinfectants or harmful chemicals to the environment. The possibilities of extending to other elastomers also widen its potential applications.

Development and application of cinnamaldehyde-loaded halloysite nanotubes for the conservation of stone cultural heritage

Essential oils and their active antimicrobial components are promising in controlling the biodeterioration of outdoor stone cultural heritage, but their high volatility, hydrophobicity, and sensitivity to light, heat, and oxygen limit their practical application. To overcome the limitations of essential oils in the conservation of outdoor stone cultural heritage, we developed a sustained release system based on halloysite nanotubes. Firstly, we acid-etched the halloysite nanotubes by 4 M HCl to increase their specific surface area and pore volume, which thereby enhanced the loading capacity of halloysite nanotubes. Then, as a model active ingredient (AI), cinnamaldehyde was loaded into acid-etched halloysite nanotubes by vacuum method. A series of experiments revealed that the cinnamaldehyde loaded into acid-etched halloysite nanotubes not only improved their thermal stability but also could be slowly released into the deionized water, following Fickian diffusion. Finally, the cinnamaldehyde-loaded halloysite nanotubes were used in field experiments on Feilaifeng limestone. After a year of monitoring, the number of microorganisms on the limestone surface was greatly reduced after the treatment of cinnamaldehyde-loaded halloysite nanotubes. The cinnamaldehyde-loaded halloysite nanotubes showed great potential in controlling the biodeterioration of outdoor stone cultural heritage.

Qualitative and quantitative analysis of the major components in Qinghao Biejia decoction by UPLC‐Orbitrap Fusion‐MS/MS and UPLC‐QQQ‐MS/MS and evaluation of their antibacterial activities

AbstractObjectiveIn the present study, the chemical components of Qinghao Biejia decoction (QBD) were qualitatively and quantitatively analyzed using UPLC‐Orbitrap Fusion‐MS/MS and UPLC‐QQQ‐MS/MS techniques, followed by identification of each component's origin and evaluation of the antibacterial activity of QBD and its components.MethodsHigh‐resolution mass spectrometry was used to obtain information on the precise molecular weight, retention time, and fragmentation ion peaks of the compounds used to identify the components of QBD and establish a method for their quantification. In vitro assays including determination of the minimal inhibitory concentration and growth curves were used to assess the antibacterial activity of QBD and its components.ResultsA total of 39 components, including fatty acids, phenolic acids, amino acids, flavonoids, coumarins, terpenoids, and alkaloids, were identified by UPLC‐Orbitrap Fusion‐MS/MS. A high‐performance analytical method was also established to quantify 12 components of QBD. The content of mangiferin was relatively high (estimated to be 814 μg/g). The results of the antibacterial assays indicated that mangiferin exhibits antibacterial effects against two strains causing respiratory tract infections.ConclusionsThe present study suggests that mangiferin may serve as a natural compound which shows high antibacterial activity. The results can aid the discovery and analysis of the active antimicrobial components present in QBD and further provide a reference for quality assessment of multi‐component herbal prescriptions.

Development of Novel Thin Polycaprolactone (PCL)/Clay Nanocomposite Films with Antimicrobial Activity Promoted by the Study of Mechanical, Thermal, and Surface Properties.

Infection with pathogenic microorganisms is of great concern in many areas, especially in healthcare, but also in food packaging and storage, or in water purification systems. Antimicrobial polymer nanocomposites have gained great popularity in these areas. Therefore, this study focused on new approaches to develop thin antimicrobial films based on biodegradable polycaprolactone (PCL) with clay mineral natural vermiculite as a carrier for antimicrobial compounds, where the active organic antimicrobial component is antifungal ciclopirox olamine (CPX). For possible synergistic effects, a sample in combination with the inorganic antimicrobial active ingredient zinc oxide was also prepared. The structures of all the prepared samples were studied by X-ray diffraction, FTIR analysis and, predominantly, by SEM. The very different structure properties of the prepared nanofillers had a fundamental influence on the final structural arrangement of thin PCL nanocomposite films as well as on their mechanical, thermal, and surface properties. As sample PCL/ZnOVER_CPX possessed the best results for antimicrobial activity against examined microbial strains, the synergic effect of CPX and ZnO combination on antimicrobial activity was proved, but on the other hand, its mechanical resistance was the lowest.

Tug-of-War-Inspired Bio-Based Air Filters with Advanced Filtration Performance.

Integrating nanostructured active materials, antimicrobial components, and rational porous structures is one of the promising approaches for simultaneously boosting removal efficiency, antimicrobial capacity, mechanical property, hydrophobic performance, and air permeability of air filters. However, realizing these performances of an air filter still remains a big challenge. Herein, a multifunctional air filter zNFs-Ag@PT, which is composed of a unique substrate prepared from Ag nanoparticles (AgNPs)-paper towel (PT) microfibers and an upper layer formed from aligned zein nanofibers (zNFs) inspired by a "tug-of-war" repulsion force, is reported. The Ag@PT substrate is fabricated via in situ reduction; and zNFs are prepared by electrospinning a well-prepared zein Pickering emulsion onto a specially designed collector. The innovative collector is a partially conductive design composed of an insulative middle section and two conductive ends. It is demonstrated that the introduction of AgNPs not only endows the zNFs-Ag@PT filter with an effective antimicrobial activity but also provides the substrate with an anisotropic electric field to achieve stretched and aligned zein fibers forming thinner nanofibers than that without AgNPs. As a result, the filtration performances of a zNFs-Ag@PT filter are enhanced. This study initiates an effective way to fabricate bio-based multifunctional air filters with antimicrobial and filtration performances via combining nano- and biotechnology.

Antimicrobial activity of bioactive components of essential oils from Citrus sinensis against important pathogens

Alternative strategies to treat multidrug resistant pathogens are indispensable due to the scarcity of new therapeutically effective antibiotics. The present work was conducted to investigate the antimicrobial effects of essential oils extracted from Citrus sinensis, locally known as “Mousami”, against various important pathogens as well as their phytochemical characterisation. Essential oils were extracted from Cit. sinensis peels by the steam distillation method, and a 0.23% yield was obtained. Chemical composition of the extracted essential oil was analysed through gas chromatography/mass spectrometry (GC/MS). The analysis revealed that the Cit. sinensis essential oil was composed of a variety of chemical compounds; mostly are monoterpene hydrocarbon and 0.62% of limonene (dipentene), as well as oxygenated monoterpenes and 0.50% limonene oxide, also known as eucalyptol. Standard reference microorganisms, i.e., E. coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Salmonella Typhi (ATCC 24682), Bacillus subtilis (ATCC 6633), Aspergillus flavus (ATCC 204304), and Candida albicans (ATCC 10231) were used, and the in vitro antimicrobial effect of Cit. sinensis essential oils was observed against these strains by disc diffusion method. Statistical analysis of the resulting data was done by using Least Significant Difference (LSD) method and Analysis of Variance (ANOVA) to assess the significant association between biological activities of essential oils at p < 0.05. Using microbroth dilution assay, maximum sensitivity was exhibited by E. coli and Can. albicans among the tested microbial strains. The zones of inhibition were significantly different, having diameters of 34.0 ± 1.5 and 55.0 ± 0.5 mm for the said bacterial and fungal strains, respectively; and their MIC values were 0.0007 ± 0.0001 and 0.0007 ± 0.0006 mg/ml, respectively. Thin layer chromatography-bioautography (TLC-bioautography) showed dipentene as biologically most active antimicrobial component. Hence, it was established that broad spectrum antimicrobial effect against important microorganisms was elucidated by essential oil extracts from Cit. sinensis that may be used as a natural antimicrobial to treat various infections caused by pathogens of public health interest.

Cefiderocol Antimicrobial Susceptibility Testing Considerations: the Achilles' Heel of the Trojan Horse?

Cefiderocol (formerly S-649266) is a novel siderophore-conjugated cephalosporin with activity against a broad array of multidrug-resistant (MDR), aerobic Gram-negative bacilli. The siderophore component binds iron and uses active iron transport for drug entry into the bacterial periplasmic space. The cephalosporin moiety is the active antimicrobial component, structurally resembling a hybrid between ceftazidime and cefepime. Like other β-lactam agents, the principal bactericidal activity of cefiderocol occurs via inhibition of bacterial cell wall synthesis by binding of penicillin-binding proteins (PBPs) and inhibiting peptidoglycan synthesis, leading to cell death. Iron concentrations need to be taken into consideration when in vitro antimicrobial susceptibility to cefiderocol is determined. Broth microdilution (BMD) and disk diffusion methods have been developed to determine in vitro activity of cefiderocol. For BMD, cation-adjusted Mueller-Hinton broth (CAMHB) requires iron depletion to provide MICs predictive of in vivo activity. A method to prepare iron-depleted CAMHB (ID-CAMHB) has been described by the Clinical and Laboratory Standards Institute (CLSI). For disk diffusion, standard Mueller-Hinton agar is recommended, presumably because iron is bound in the medium. Currently, clinical FDA and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints and investigational (research-use-only) CLSI breakpoints exist for interpreting cefiderocol susceptibility results for certain Gram-negative bacilli. Cefiderocol does not have clinically relevant activity against Gram-positive or anaerobic organisms. FDA or EUCAST breakpoints should be applied to interpret results for Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii complex for patient care until the investigational status has been removed from CLSI breakpoints. Further clinical outcome data are required to assess the effectiveness of cefiderocol for treatment of other Acinetobacter species (non-baumannii complex) and Stenotrophomonas maltophilia at this time, and, as such, antimicrobial susceptibility testing of these organisms should be limited to research use in the scenario of limited treatment options.

Antimicrobial Coatings for Food Contact Surfaces: Legal Framework, Mechanical Properties, and Potential Applications.

Food contact surfaces (FCS) in food processing facilities may become contaminated with a number of unwanted microorganisms, such as Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcus aureus. To reduce contamination and the spread of disease, these surfaces may be treated with sanitizers or have active antimicrobial components adhered to them. Although significant efforts have been devoted to the development of coatings that improve the antimicrobial effectiveness of FCS, other important coating considerations, such as hardness, adhesion to a substrate, and migration of the antimicrobial substance into the food matrix, have largely been disregarded to the detriment of their translation into practical application. To address this gap, this review examines the mechanical properties of antimicrobial coatings (AMC) applied to FCS and their interplay with their antimicrobial properties within the framework of relevant regulatory constraints that would apply if these were used in real-world applications. This review also explores the various assessment techniques for examining these properties, the effects of the deposition methods on coating properties, and the potential applications of such coatings for FCS. Overall, this review attempts to provide a holistic perspective. Evaluation of the current literature urges a compromise between antimicrobial effectiveness and mechanical stability in order to adhere to various regulatory frameworks as the next step toward improving the industrial feasibility of AMC for FCS applications.

Tannin profile, antioxidant properties, and antimicrobial activity of extracts from two Mediterranean species of parasitic plant Cytinus

BackgroundCytinus is small genus of endophytic parasitic plants distributed in South Africa, Madagascar, and in the Mediterranean region. In the latter area, two species occur, Cytinus hypocistis and C. ruber, distinguished by both morphological characters and ecological traits. We characterized the ethanolic and aqueous extracts obtained from the inflorescences of C. hypocistis and C. ruber collected in Sardinia, Italy, and explored their tannin content, antioxidant properties and antimicrobial activities.MethodsTotal phenolic contents were determined by Folin-Ciocalteu spectrophotometric method. Tannin content was determined by HPLC. Antioxidant activity of the extracts was tested with both electron transfer-based (FRAP, TEAC, DPPH) and spectrophotometric HAT methods (ORAC-PYR). The antimicrobial activities of extracts/compounds were evaluated using the broth microdilution method. The bactericidal activity was evaluated using the time-kill method. Biofilm formation was evaluated by crystal violet (CV) staining assay.ResultsCharacterization of the tannin profile of C. hypocistis and C. ruber revealed a significant amount of gallotannins, in particular 1-O-galloyl-β-D-glucose. In addition, pentagalloyl-O-β-D-glucose was present in all extracts, reaching the concentration of 0.117 g/kg in the ethanolic extract of C. hypocistis. C. hypocistis extracts displayed a strongest antioxidant activity than C. ruber extracts. Three Gram-positive bacterial species tested (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium) resulted sensitive to both Cytinus extracts, with MICs ranging from 125 to 500 μg/ml for aqueous extracts and from 31.25 to 250 μg/ml for ethanolic extracts; on the contrary, Gram-negative strains (Pseudomonas aeruginosa and Klebsiella pneumoniae) were not affected by Cytinus extracts. Intriguingly, we observed the suppressive activity of ethanolic extracts of C. hypocistis and C. ruber on biofilm formation of S. epidermidis. Experiments performed with synthetic compounds indicated that pentagalloyl-O-β-D-glucose is likely to be one of the active antimicrobial components of Cytinus extracts.ConclusionsThese findings show that Cytinus extracts have antimicrobial and antioxidant activities, suggesting a possible application of Cytinus as sources of natural antimicrobials and antioxidants.

Antimicrobial Silver-Polyethyleneimine-Polylactic Acid Polymer Composite Film for Coating Methacrylate-Based Denture Surfaces

To prepare an antimicrobial polymer composite composed of silver- (Ag-) polyethyleneimine- (PEI-) polylactic acid (PLA) in chloroform, for coating the mucosal surfaces of methacrylate-based dentures as a prospective therapy for denture stomatitis.The water-insoluble, tightly bound, hard, micrometre-thin, and colourless film exerts its effects by direct contact with the pathogens and via the active constituents (Ag, PEI, and Ag-PEI) released slowly into the mucosa’s salivary layer. Silver and PEI were blended at 140°C, then bound to PLA. The Ag-PEI complex was characterised by dynamic light scattering and transmission electron microscopy, and the Ag-PEI-PLA composite was examined by atomic force microscopy and micro-computed tomography. The characteristic was measured by atomic force microscopy (AFM) and micro-computed tomography (micro-CT). The quantity of water-soluble Ag-PEI complex released from the composite film was measured with gravimetry. The cellular physiological effects were analysed by impedimetry and computer-based morphometry using human gingival epithelial cells. A real-time cell proliferation assay revealed moderate toxic effects of Ag-PEI on the epithelium. The viscous Ag-PEI-PLA solution produced could be applied as a thin film on methacrylate surfaces. Active antimicrobial components (Ag, PEI, and Ag-PEI) were released from the hard, tightly bound Ag-PEI-PLA coating. This study’s findings verified the applicability of the antimicrobial Ag-PEI-PLA composite for coating the inner surfaces of acrylate dentures. Owing to the well-known antimicrobial effects of silver and PEI and the supplementary effects of chloroform, this composite provides a new therapeutic method for denture stomatitis that can be easily performed by dentists.

Antiradical and Antibacterial Activity of Essential Oils from the Lamiaceae Family Plants in Connection with their Composition and Optical Activity of Components

Antiradical activity of essential oils of korean mint (Agastache rugosa (Fisch. et Mey)), blue giant hyssop (Agastache foeniculum (Pursh) Kuntze), hyssop (Hyssopus officinalis L.), lavander (Lavandula angustifolia L.), peppermint (Mentha piperita L.), lemon mint (Mentha piperita var. citrata (Ehrh.) Briq), monarda (Monarda fistulosa L.), oregano (Origanum vulgare L.), common sage (Salvia officinalis L.), clary (Salvia sclarea L.), and winter savory (Satureja montana L.) cultivated in the Central Botanical Garden of NAS of Belarus was investigated in the reaction with the cation-radicals of 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+·). The most pronounced antiradical activity was observed for the essential oils with a high content of phenolic compounds: winter savory and monarda. Antiradical properties of the essential oils and individual phenolic and terpene compounds (eugenol, carvacrol, thymol, citral, (+)-pulegone) in the reaction with ABTS+· significantly differ in aqueous solutions and ethanol-water mixtures. Нigh antibacterial activity of selected components of essential oils from the Lamiaceae plants, carvacrol, citral, and linalool, towards test organisms Sarcina lutea, Esherichia coli, Staphylococcus saprophyticus, Pseudomonas fluorescens, Bacillus megaterium, Pseudomonas putida was shown. The antibacterial activity of enantiomers of pinene and limonene was determined. The dextrorotary isomer of α-pinene possesses a significantly higher level of activity as compared with the levorotary one. S-(-)-limonene proves itself as a more active antimicrobial component towards Sarcina lutea and Staphylococcus saprophyticus than R-(+)-limonene. Both enantiomers show comparable activity towards Esherichia coli. Due to the high antibacterial activity the essential oils from Satureja montana and Monarda fistulosa can be considered as effective antibacterial agents.

Clove and cinnamon essential oils in dulce de leche

PurposeThe purpose of this study was to analyze lipid oxidation and microbiological, physical, chemical and sensory attributes of dulce de leche.Design/methodology/approachDulce de leche samples were produced from various essential oil (EOs), control (no EO), clove, cinnamon and a clove and cinnamon mixture. After manufacturing, the products were stored at 25°C for 210 days. During storage, the samples were analyzed for texture, color, protein, lipids, lipid oxidation, pH, moisture, ash and enumeration of Salmonella sp., coliforms at 45°C, Staphylococcus sp. coagulase positive and mesophilic bacteria. The sensory analysis used a hedonic scale for appearance, smell, taste and texture attributes and overall acceptance.FindingsThe addition of EOs (clove and cinnamon) did not alter (p > 0.05) the proximal composition, texture, color or sensory attributes of dulce de leche. All products presented a good acceptance rate (>70 per cent). However, among the samples containing EO, dulce de leche with cinnamon presented a higher acceptance (81.67 per cent), and after 210 days of storage, it had lower (40.9 μg malonaldehyde/g p-value <0.01) lipid oxidation. Microbiological analyses indicated that the EOs are active antimicrobial components and are viable inclusions in this type of product.Originality/valueThe inclusion of EOs in dulce de leche provided an overall sensory acceptance similar to the traditional product and all products, including the control, were comparable. Dulce de leche produced with EOs is marketable.

CHEMICAL AND MICROBIAL STUDY OF MANGO AND APRIOT KERNELS SEEDS AND ITS EFFECT IN THE BEEF BURGER PRODUCTS

Abstract Meat is a perishable food. both mango and apricot seed kernel extract can use as a natural food additive for extending the shelf-life of a variety of food products. The aim of the present work was to study the antioxidant and antimicrobial effect of ethanol apricot and mango seed kernels extract in beef burger stored at refrigerator temperature for different periods of time. The protein and fat content in apricot kernel extract (ASK) was five time higher than mango kernel extract (MSK). The ASK extract contain unsaturated fatty acids much higher than MSK. Vanillic was the highest amount of total polyphenols compounds found in ethanol mango kernel. While, pyrogallol was the highest compounds found in ethanol apricot kernel. Fresh samples that treated with sodium nitrite tended to have the lowest APC among all different samples investigated immediately after preparation. Both beef burger sample treated with mango and apricot kernels extract have APC lower than untreated samples. Sample treated with mango kernels extract had the lowest APC among all investigated samples after storage for 30 days. Accordingly, both extracts had a high nutritive value and broad antimicrobial spectrum against gram-positive and gram-negative bacteria. Moreover, the active antimicrobial component may be due to polyphenols found in both extracts. Key words: Mango, Apricot, Kernel, Polyphenols, Antibacterial and Burger

Antibacterial Kaolinite Based Nanocomposites

In this study we focused on antimicrobial nanocomposites based on kaolinite, when two series of nanocomposites were prepared. In the first case, kaolinite (KAO) was used as the carrier for antibacterial drug. Secondly, kaolinite modified with dimethyl sulphoxide (DMSO) was used. In both series, chlorhexidine dihydrochloride (CH) acts as an active antimicrobial component. The resultant samples were characterized by X – ray diffraction (XRD) and infrared spectroscopy (FTIR). The antimicrobial activity of prepared composites against bacteria strains Staphylococcus aureus, Escherichia coli and against yeast Candida albicans were evaluated by finding minimum inhibitory concentration (MIC). It was found that prepared nanocomposites were very effective and they had different effect against bacteria strains and yeast. Important information was that treatment with DMSO had not significant effect on antimicrobial activity. These nanocomposites can be in future used for preparation of drugs for local treatment of oral cavity with long-acting antimicrobial activity.

Antibacterial effects of conventional glass ionomer cement.

The antibacterial activity of conventional glass ionomer cement against three different microorganism strains alone and following incorporation of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride was evaluated. Agar diffusion method was used to determine the inhibitory effect of the conventional glass ionomer cement ChemFlex on Streptococcus mutans, Lactobacillus casei and Actinomyces viscosus. Bacterial strains were inoculated into BHIB, and incubated in an anaerobic atmosphere (37 °C). From the bacteria grown in the liquid medium, the density of the inoculum was set to be equivalent to McFarland 2 standard. In Shaedler agar, 350 μL of the bacterial suspension were equally spread. Specimens (4 mm × 6 mm) were prepared from the cement without and with addition of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride. The inhibition zones were determined after 48 hours, after 2, 7 and 21 days of incubation. The combination ChemFlex + Benzalkonium Chloride has the best effect on the three analysed bacteria. The Benzalkonium Chloride antibacterial compound has a stronger antibacterial effect than Cetylpyridinium Chloride. Glass ionomer cements can potentially be used as a medium for slow release of active antimicrobial components, and they have the potential to improve clinical outcomes of the cements (Tab. 3, Fig. 3, Ref. 31).

The large scale antibacterial, antifungal and anti-phage efficiency of Petamcin-A: new multicomponent preparation for skin diseases treatment.

BackgroundHuman and animal skin diseases of bacterial, fungal and viral nature and their complications are widespread and globally cause a serious trouble. Their prevalence is increasing mainly due to drug resistance. Consequently, demand has increased for new effective antimicrobial drugs, which also should be less toxic, possess a wider spectrum of action and be economically more beneficial. The goal was to investigate antibacterial, antifungal and anti-phage activity of Petamcin-A-a new multicomponent preparation. It contains acetic acid and hexamethylenetetramine as main active antimicrobial components, as well as phosphatidylcholine, tocopheryl acetate and glycerol as excipients.MethodsBacteriostatic activity and minimal inhibitory concentrations of the preparation against various test-organisms were determined by agar well diffusion assay. Antifungal activity was tested by agar dilution assay. To explore anti-phage activity double agar overlay plaque assay was used. Nystatin, chlorhexidine and acetic acid were used as control agents for comparative analysis. Statistical analysis was done with GraphPad Prism 5.03 or R 3.1.0 software.ResultsThe results showed a higher activity of Petamcin-A against all bacterial and fungal test strains compared with its components or control agents. The preparation was more effective against tested gram-positive bacteria than gram-negative ones. Petamcin-A expressed bactericidal activity against almost all test strains. In addition, the preparation demonstrated high activity against T4 phage of Escherichia coli C-T4 completely inhibiting its growth. 5-fold diluted Petamcin-A also exhibited considerable activity reducing phage concentration by 2.6 Log10.ConclusionsPetamcin-A has a high antimicrobial activity against all tested strains of bacteria, yeasts and moulds. The preparation also exhibited high anti-phage activity. Moreover, taking into account that Petamcin-A has no observable toxicity on skin and its components are not expensive, it can be advantageous for management of various skin medical conditions.

A low-cost, hands-on module to characterize antimicrobial compounds using an interdisciplinary, biophysical approach.

We have developed a hands-on experimental module that combines biology experiments with a physics-based analytical model in order to characterize antimicrobial compounds. To understand antibiotic resistance, participants perform a disc diffusion assay to test the antimicrobial activity of different compounds and then apply a diffusion-based analytical model to gain insights into the behavior of the active antimicrobial component. In our experience, this module was robust, reproducible, and cost-effective, suggesting that it could be implemented in diverse settings such as undergraduate research, STEM (science, technology, engineering, and math) camps, school programs, and laboratory training workshops. By providing valuable interdisciplinary research experience in science outreach and education initiatives, this module addresses the paucity of structured training or education programs that integrate diverse scientific fields. Its low-cost requirements make it especially suitable for use in resource-limited settings.

Preparation, characterization and antimicrobial activity of chitosan microparticles with thyme essential oil

Considering the therapeutic effects of formulations with violate essential oils, development of an available drug delivery system is of great interest, especially assuming the fact that using essential oils as antimicrobial agents is a rather expanded in antimicrobial therapy nowadays. In this work, chitosan microparticles with encapsulated thyme essential oil were prepared by the emulsion cross-linking method. The effect of thyme oil and glutaraldehyde initial concentrations on particle size, morphology, and particle size distribution was investigated. In addition, the influence of these parameters on the encapsulation of thyme oil in chitosan microparticles, concerning thyme oil loadings and encapsulation efficiency was also tested. The particles showed a spherical shape with an average diameter from 4.71?1.42 to 13.65?4.34 m, depending on the concentration of the essential oil and glutaraldehyde that were used. The diameter of microparticles appeared to increase with increasing the thyme essential oil concentration, and decreased with the increase of glutaraldehyde concentration. It was shown that the concentration of glutaraldehyde did not affect the degree of encapsulation, but the increase in the initial concentration of thyme oil increased the degree of encapsulation of this essential oil in chitosan microparticles. All particles containing thyme essential oil, as well as essential oil of thyme itself showed significant antimicrobial activity against Staphylococcus aureus ATCC 25923, Esherichia coli ATCC 25922, Candida albicans ATCC 24433, Enterococcus faecalis ATCC 25929. This study showed a great potential of the use of thyme essential oil as an antimicrobial agent, especially when encapsulated in a drug delivery system with controlled release of the active antimicrobial component.

Antimicrobial activity of the bioactive components of essential oils from Pakistani spices against Salmonella and other multi-drug resistant bacteria

BackgroundThe main objective of this study was the phytochemical characterization of four indigenous essential oils obtained from spices and their antibacterial activities against the multidrug resistant clinical and soil isolates prevalent in Pakistan, and ATCC reference strains.MethodsChemical composition of essential oils from four Pakistani spices cumin (Cuminum cyminum), cinnamon (Cinnamomum verum), cardamom (Amomum subulatum) and clove (Syzygium aromaticum) were analyzed on GC/MS. Their antibacterial activities were investigated by minimum inhibitory concentration (MIC) and Thin-Layer Chromatography-Bioautographic (TLC-Bioautographic) assays against pathogenic strains Salmonella typhi (D1 Vi-positive), Salmonella typhi (G7 Vi-negative), Salmonella paratyphi A, Escherichia coli (SS1), Staphylococcus aureus, Pseudomonas fluorescens and Bacillus licheniformis (ATCC 14580). The data were statistically analyzed by using Analysis of Variance (ANOVA) and Least Significant Difference (LSD) method to find out significant relationship of essential oils biological activities at p <0.05.ResultsAmong all the tested essential oils, oil from the bark of C. verum showed best antibacterial activities against all selected bacterial strains in the MIC assay, especially with 2.9 mg/ml concentration against S. typhi G7 Vi-negative and P. fluorescens strains. TLC-bioautography confirmed the presence of biologically active anti-microbial components in all tested essential oils. P. fluorescens was found susceptible to C. verum essential oil while E. coli SS1 and S. aureus were resistant to C. verum and A. subulatum essential oils, respectively, as determined in bioautography assay. The GC/MS analysis revealed that essential oils of C. cyminum, C. verum, A. subulatum, and S. aromaticum contain 17.2% cuminaldehyde, 4.3% t-cinnamaldehyde, 5.2% eucalyptol and 0.73% eugenol, respectively.ConclusionsMost of the essential oils included in this study possessed good antibacterial activities against selected multi drug resistant clinical and soil bacterial strains. Cinnamaldehyde was identified as the most active antimicrobial component present in the cinnamon essential oil which acted as a strong inhibitory agent in MIC assay against the tested bacteria. The results indicate that essential oils from Pakistani spices can be pursued against multidrug resistant bacteria.

Inhibition of Microorganisms on a Carrion Breeding Resource: The Antimicrobial Peptide Activity of Burying Beetle (Coleoptera: Silphidae) Oral and Anal Secretions

Competition between scavengers and microorganisms for the nutrients within carrion is well documented. As a significant contributor to food web energetics, carrion serves not only as a food source for scavengers, but also as a reproductive resource for many insects. One example are the burying beetles of the Nicrophorus genus (Coleoptera: Silphidae) whose reproduction is dependent on locating and successfully sequestering vertebrate carrion. Throughout the cooperative preparation of carrion and feeding of the larval offspring, parental beetles coat the carrion with oral and anal secretions known to attenuate the growth of molds and bacteria in the laboratory. We test the hypotheses that Nicrophorus secretions attenuate the growth of naturally occurring microorganisms likely to be found colonizing the carrion resource, and that the active antimicrobial components of the secretions are small antimicrobial peptides (AMPs) similar to those produced by other insects.