High Antimicrobial Activity Research Articles

Cell Adhesion, Elasticity, and Rupture Forces Guide Microbial Cell Death on Nanostructured Antimicrobial Titanium Surfaces.

Naturally occurring and synthetic nanostructured surfaces have been widely reported to resist microbial colonization. The majority of these studies have shown that both bacterial and fungal cells are killed upon contact and subsequent surface adhesion to such surfaces. This occurs because the presence of high-aspect-ratio structures can initiate a self-driven mechanical rupture of microbial cells during the surface adsorption process. While this technology has received a large amount of scientific and medical interest, one important question still remains: what factors drive microbial death on the surface? In this work, the interplay between microbial-surface adhesion, cell elasticity, cell membrane rupture forces, and cell lysis at the microbial-nanostructure biointerface during adsorptive processes was assessed using a combination of live confocal laser scanning microscopy, scanning electron microscopy, in situ amplitude atomic force microscopy, and single-cell force spectroscopy. Specifically, the adsorptive behavior and nanomechanical properties of live Gram-negative (Pseudomonas aeruginosa) and Gram-positive (methicillin-resistant Staphylococcus aureus) bacterial cells, as well as the fungal species Candida albicans and Cryptococcus neoformans, were assessed on unmodified and nanostructured titanium surfaces. Unmodified titanium and titanium surfaces with nanostructures were used as model substrates for investigation. For all microbial species, cell elasticity, rupture force, maximum cell-surface adhesion force, the work of adhesion, and the cell-surface tether behavior were compared to the relative cell death observed for each surface examined. For cells with a lower elastic modulus, lower force to rupture through the cell, and higher work of adhesion, the surfaces had a higher antimicrobial activity, supporting the proposed biocidal mode of action for nanostructured surfaces. This study provides direct quantification of the differences observed in the efficacy of nanostructured antimicrobial surface as a function of microbial species indicating that a universal, antimicrobial surface architecture may be hard to achieve.

The first representatives of phosphonium salts based on the ammonium acylhydrazone scaffold: synthesis and biological activity

The acid-catalyzed reaction of substituted benzaldehydes with Girard’s reagent T leads to the formation of new water-soluble mixed ammonium-phosphonium salts. The obtained compounds exhibit high antimicrobial and moderate antitumor activities with low hemotoxicity.

Improving the Antibacterial Properties of Dental Bonding Materials Loaded with Silver Compounds.

Biofilm accumulation, the appearance of white spot lesions and the development of secondary caries are the main complications in orthodontic patients. A promising approach to fight this situation is the development of adhesive cements with improved antibacterial properties. The aim of the present study was to evaluate the possibility of improving the antibacterial properties of glass ionomer cements by incorporating different types of antimicrobial compounds without altering their physical and mechanical properties. Different concentrations of silver carbonate (SC) and an inorganic glass with encapsulated silver were added to the glass ionomer cement, as well as chitosan, to achieve synergistic antibacterial activity. Variations in the antibacterial capacity were evaluated using the agar diffusion test; the potential alteration of the physical and mechanical properties of the material was analyzed by the shear bond strength test. SEM characterization and colorimetric evaluation were also conducted. Samples of SC up to 1% and inorganic glass with encapsulated silver up to 5% showed significant improvement in their antibacterial ability without compromising shear strength. The highest antimicrobial activity was observed for Lactobacillus acidophilus, with inhibition zones of 3.8 and 3.1 mm for SC and inorganic glass, respectively. The characterization of the samples did not detect any major structural changes between the different samples. The only group that underwent a noticeable color change was the group with SC. The results show that the incorporation of silver carbonate and inorganic glass with encapsulated silver provided the glass ionomer cement with an antibacterial capacity without compromising the bond strength and without modifying the structure of the material.

Chemical profile, antioxidant and antimicrobial activity of Pinus heldreichii Christ. Distributed in Bulgaria

Pinus heldreichii Christ. (Bosnian pine), a Tertiary relict and Balkan sub-endemic, has not been comprehensively studied for its essential oil (EO) profile and bioactivity of its different plant parts. This study aimed to determine the EO yield, composition and antimicrobial activity from different parts of P. heldreichii at three different populations (mountains) in Bulgaria. Furthermore, the study assessed the antioxidant activities of plant tissue, including leaves (needles), twigs wood, male and female cones. The EOs yield from different plant parts ranged from 0.09 % (leaves) to 0.74 % (wood of twigs), with monoterpenes being the predominant class. Limonene, α-pinene, β-caryophyllene, germacrene D, β-pinene, and β-myrcene were detected in the EO extracted from all analyzed trees. However, these compounds were not found in the EO extracted from all plant parts of the same trees. Four chemical groups (chemotypes) were identified for EO from twigs, and three chemotypes were identified for EO from leaves. The chemotypes were based on the percent ratio of the main EO constituents (>5 %). Leaves tissue showed the highest values in terms of polyphenols and flavonoids, as well as higher ABTS radical scavenging activity, while the highest antimicrobial activity against Staphylococcus aureus subsp. aureus was seen in the EOs obtained from twigs. This is the first study to identify several chemotypes based on leaf and twigs EO of P. heldreichii distributed in Bulgarian flora. Furthermore, the EO of twigs tips (TT), male cones (MC), and wood of one-two-year-old twigs (WT) of the same trees were reported for the first time. The total polyphenol, flavonoid content, and radical scavenging activity of tissues of annual twigs wood and biennial twigs wood, leaf tissue, MC tissue, and the twigs tips tissue is also reported for the first time in the accessible literature. These findings highlight the potential of P. heldreichii to provide EOs with varying compositions and bioactivities, making them suitable for nutraceutical, pharmacological, and potentially food additive applications. Furthermore, the identification of chemotype accessions in this study suggests their selection for the development of new forest crop as a source for natural products with desirable composition and bioactivity.

Selenium nanoparticles coated bacterial polysaccharide with potent antimicrobial and anti-lung cancer activities

Bacterial exopolysaccharides are homopolymeric or heteropolymeric polysaccharides with large molecular weights (10–1000 kDa). Exopolysaccharides' functional uses and potential have revolutionized the industrial and medicinal industries. Hence, the aim of the present study was to optimize the production of bacterial exopolysaccharide and apply it as a capping agent for selenium nanoparticles synthesis. Exopolysaccharide (EPS) producing Lactic acid bacteria (LAB) were isolated from dairy products then biochemically characterized and assessed for their potential antimicrobial effect. The most potent EPS producer was identified as Lactiplantibacillus plantarum strain A2 with accession number OP218384 using 16S rRNA sequencing. Overall, FTIR data of the extracted EPS revealed similarity with amylopectin spectrum. 1H NMR spectrum revealed an α-anomeric configuration of the glycosidic linkage pattern in the polysaccharides while the 13C NMR spectrum can also be separated into two main portions, the anomeric carbons region (δ 98–102 ppm) and the non-anomeric carbons region (δ 60–81 ppm). Antimicrobial activity of the produced EPS showed maximum activity against Staphylococcus aureus, MRSA, Enterobacter aerogenes, Klebsiella pneumoniae and Candida albicans respectively. The EPS capsule layer surrounding the bacterial cells was detected by TEM study. Optimization of EPS production was evaluated using Taguchi design, trial 23 reported the highest biomass yield and EPS output (6.5 and 27.12 g/L respectively) with 2.4 and 3.3 folds increase (from the basal media) respectively. The optimized exopolysaccharide was used as a capping and stabilizing agent for selenium nanoparticles (EPS-SeNPs) synthesis. Zeta potential, size and PDI of the synthesized nanoparticles were − 19.7 mV, 45–65 nm and 0.446 respectively with strong bactericidal and fungicidal effect against the tested pathogens. Complete microbial growth eradication was recorded after 6, 8 and 10 h against Staphylococcus aureus, Candida albicans and Klebsiella pneumoniae respectively. EPS-SeNPs showed a potent antioxidant effect reached 97.4% and anticancer effect against A549 lung cancer cell line (IC50 reached 5.324 µg/mL). EPS-SeNPs inhibited cancerous cell growth at S phase. Moreover, molecular studies revealed the anti-apoptotic activity of Bcl2's was inhibited and Bax was activated. The present investigation successfully synthesized selenium nanoparticles through bacterial EPS with significantly high antimicrobial and anticancer activity.

CHEMICAL COMPOSITION AND ANTIBACTERIAL ACTIVITY OF ESSENTIAL OIL OF $MENTHA~ARVENSIS$ L. HARVESTED AT HIGH ALTITUDE ARMENIAN FLORA

Currently it is relevant to reveal possible new sources of natural antibacterial components, the mechanisms of antibiotic resistance formation in bacteria, and the possible ways to overcome the problem of microbial resistance to antibiotics. So, our research aimed to study the chemical composition and antibacterial activity of the essential oil (EO) isolated from the herb Mentha arvensis harvested at high altitude Armenian landscape. Menthol constitutes a significant part of the EO components of the M. arvensis plant, reaching approximately 70%. The investigated EO showed high antimicrobial activity against several Gram-positive and Gram-negative bacterial strains. In particular, the EO equally suppressed the growth of both wild-type and kanamycin-resistant strains of Escherichia coli and manifested the minimal inhibitory concentration against all tested microorganisms of 0.18 mg/mL. So, M. arvensis EO is relevant for application in the food and cosmetic industry as a natural aromatizer and preservative.

One-step silver coating of polypropylene surgical mask with antibacterial and antiviral properties

Face masks can filter droplets containing viruses and bacteria minimizing the transmission and spread of respiratory pathogens but are also an indirect source of microbes transmission.A novel antibacterial and antiviral Ag-coated polypropylene surgical mask obtained through the in situ and one-step deposition of metallic silver nanoparticles, synthesized by silver mirror reaction combined with sonication or agitation methods, is proposed in this study.SEM analysis shows Ag nanoparticles fused together in a continuous and dense layer for the coating obtained by sonication, whereas individual Ag nanoparticles around 150 nm were obtained combining the silver mirror reaction with agitation. EDX, XRD and XPS confirm the presence of metallic Ag in both coatings and also oxidized Ag in samples by agitation. A higher amount of Ag nanoparticles is deposited on samples by sonication, as calculated by TGA. Further, both coatings are biocompatible and show antibacterial properties: coating by sonication caused 24 % and 40 % of bacterial reduction while coating by agitation 48 % and 96 % against S. aureus and E. coli, respectively. At 1 min of contact with SARS-CoV-2, the coating by agitation has an antiviral capacity of 75 % against 24 % of the one by sonication. At 1 h, both coatings achieve 100 % of viral inhibition. Nonetheless, larger samples could be produced only through the silver mirror reaction combined with agitation, preserving the integrity of the mask.In conclusion, the silver-coated mask produced by silver mirror reaction combined with agitation is scalable, has excellent physico-chemical characteristics as well as significant biological properties, with higher antimicrobial activities, providing additional protection and preventing the indirect transmission of pathogens.

Waste to health: Green synthesis of Zn loaded LTA zeolite prepared from waste glass and aluminum scrap with high antioxidant and antimicrobial activities

The aim of this study is to evaluate the in vitro antibacterial and the antioxidant activities of low cost ZnO@Zn-ZF2 zeolite. The carrier was Na-LTA type zeolite prepared from waste glass and aluminum scraps by alkaline fusion at 550 °C using NaOH as mineralizer followed by hydrothermal crystallization at 60 °C for 6 days. Three samples of ZnO@Zn-ZF2 were prepared with different amount of zinc (2, 4 and 6 wt%). The antioxidant activities of ZnO@Zn-ZF2 zeolite were evaluated by different methods, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power and β-carotene bleaching assay. All particles showed interesting antioxidant activities. Further, the prepared samples exhibited considerable antibacterial activity against Gram- and Gram + bacteria. The obtained results showed that 6ZnO@Zn-ZF2 zeolite had the highest antioxidant and antibacterial activities against Klebsiella pneumoniae and Micrococcus luteus, which can be attributed to the good dispersion of ZnO particles on the zeolite surface.

Oxidation reactions of cyclopent-2-en-1-yl thiophene derivatives

Introduction: Thiophene derivatives are common in a large number of natural compounds. In addition, their biological activity provides great opportunities for synthetic organic chemistry. In particular, cyclopentenylthiophenes have high antimicrobial activity, can affect various inflammatory mechanisms, and can be effective in the treatment of cancer. However, in research, it is essential to first learn how to obtain compounds in pure form and to select such synthesis conditions that, when scaled up and introduced into widespread production, the affordability and safety of the processes would meet the needs of both consumers and pharmaceutical companies. Material and Methods: As an oxidant, meta-chloroperoxybenzoic acid was used, which allowed exploring its oxidative properties and advantages of use in more detail. Results and Discussion: In the course of this work, several cyclopentenylthiophene derivatives were synthesised, the ratio of isomers in the synthesis of these compounds was analysed, and the advantages and disadvantages of the synthesis methods were discussed. On the other hand, there are several issues that require additional research, including the effect of temperature conditions, electrophilicity of substituents and other factors on the course of the epoxidation reaction for cyclopentenylthiophenes. Conclusion: The research of thiophene derivatives is relevant both from the standpoint of exploring electronic effects when substituents with different acceptor properties are introduced into the heterocyclic aromatic system and from the standpoint of medicinal chemistry, as they are interesting biologically active objects with high chemical stability, good penetration of cell membranes, ability to affect enzyme activity, bind to receptors.

The Study of Sustainable Biodesinfectants for Pig Farms in Samosir Island, Indonesia

Disease control in smallholder pig farms has not been appropriately taken care of on Samosir Island. Pig livestockers suffer a lot of losses due to bacterial infection. Reducing the bacterial population in the pigsty is beneficial for minimizing the access of animals infected with bacteria. One way is by applying a disinfectant. This study investigated the ability of alternative biodesinfectants with four concentrations to eliminate pig-associated Escherichia coli and Salmonella by in-vitro tests. Sustainable biodesinfectans are fermented fruit extract (FFE), and fermented fruits extract plus Agave sisalana (FFE +AS). The antimicrobial activity testing method was the diffusion method with a paper disc. Fermentation of fruit waste to produce FFE is more beneficial than disposing of the waste at a landfill. In this study, the fruit waste used comes from pineapple (Ananas comosus), papaya (Carica papaya), and banana (Musa paradisiaca). FEE + AS is FEE, which refermented to the addition of Agave sisalana. FFE and FFE + AS contain enzymes, organic acids, and microbial. The results showed that FEE +AS 100%, 1: 10, and 1:20 prove to inhibit Escherichia coli and Salmonella. The highest antimicrobial activity was obtained from FEE + AS with an 11.7 mm inhibition zone diameter. Further studies on disinfecting pig sheds are justified to assess their effectiveness.

Geranium tuberosum Metanol Ekstraktının Enzim İnhibitör Özellikleri ve Antimikrobiyal Aktivitesi

Geranium tuberosum roots are consumed fresh in some areas of the countryside of Turkey. This study was conducted to scientifically validate the traditional use of the species. The enzyme inhibition effect and antimicrobial activity of the root and leaf parts of Geranium tuberosum were investigated using a methanol extract. The leaf extract had higher acetylcholinesterase and butyrylcholinesterase activity than the root extract, while the root extract showed a stronger inhibitory effect on xanthine oxidase enzyme.. Also, the antifungal and antibacterial activities of the extracts were investigated using the hollow agar technique. It was observed that both extracts gave high antimicrobial activity on different bacterial strains. These results confirmed that Geranium tuberosum is a natural antibacterial, and has enzyme inhibitory potential.

Evaluation of antimicrobial activity of a herbal mixture

Due to adverse effects of using allopathic medicines, the use and search for pharmaceuticals made from plants has increased recently. A mixture of herbal extracts known as “Chukku Kashaya” is widely used as home remedy in Kerala for respiratory disorders. Additionally, it relieves cold and fever symptoms. The present investigation focused on evaluating the antimicrobial activity of methanolic extracts obtained by soxhlet extraction of leaves of Ocimum tenuiflorum and Plectranthus amboinicus and fruits of Piper nigrum and rhizome of Zingiber officinalae and their combination in equal ratios and their activity was determined using agar well diffusion method against Staphylococcus aureus (gram positive), Klebsiella pneumoniae (gram negative), and Pseudomonas aeruginosae (gram negative). Streptomycin was used as positive control. Zingiber officinalae showed maximum zone of inhibition against all the bacteria and herbal mixture showed moderate zone of inhibition. The mixture was more active than Ocimum tenuiflorum , Piper nigrum and Plectranthus amboinicus. Staphylococcus aureus was shown to be the most sensitive to all the extracts and herbal mixtures, whereas Klebsiella pneumoniae showed the least activity. Though Z.officinalae has higher antimicrobial activity, there is limited literature support to prove its activity against fever, cold and other symptoms of respiratory tract infections. Z.officinalae is mainly used for GI related disorders. This herbal blend is more efficient because it includes of O.tenuiflorum : having antipyretic, analgesic and voice improving activity ; P.amboinicus: providing relief from cough, asthma, bronchitis and other symptoms of respiratory tract infections; P. nigrum which can improve appetite and digestion .

Phytochemical analysis, antioxidant, and antimicrobial activities of Jordanian Pomegranate peels.

Pomegranate (Punica granatum) peels have shown numerous health benefits such as antioxidant, anti-inflammatory, and antimicrobial activities. These health activities are owed to the unique phytochemical components present in pomegranate peels. Variations in the pomegranate cultivar, geographical region, and extraction methods significantly affect the phytochemical composition and concentrations of pomegranate fruits and their peels, hence their health outcomes. Therefore, this study aimed to examine the phytochemical contents of pomegranate peels of Jordanian origin and their antioxidant and antimicrobial activities. Among the 6 extracts of pomegranate peels tested, the ethanol extract exhibited the highest total phenolic content (TPC = 297.70 ± 1.73 mg GAE/g DW), highest total flavonoids content (TFC = 116.08 ± 3.46 mg RE/g DW), highest hydrolyzable tannins (HT) contents (688.50 ± 3.54 mg TE/g DW). Whereas the highest condensed tannins (CT) content was found in both the ethanol (13.87 ± 0.58 mg CE/g DW) and methanol (13.84 ± 0.55 mg CE/g DW) extracts. For the antioxidant activities, the water extract of pomegranate peels displayed the highest inhibitory effect on DPPH radicals (9.43 ± 0.06 μmole TE/g DW), while for the ABTS+ assay the methanol and ethanol extracts exhibited the highest activities of 11.09 ± 0.02 and 11.09 ± 0.06 μmole TE/g DW, respectively. For the FRAP assay, the aqueous methanol extract exhibited the highest reducing activity (1.60 ± 0.09 mmole Fe (II)/g DW). As for the antimicrobial activities of various extracts of pomegranate peels, the highest antimicrobial activity against Micrococcus luteus was achieved by the ethanol extract (MIC = 6.25 mg/mL), whereas the lowest antimicrobial activity was observed against Candida krusei using the methanol extract (MIC = 100 mg/mL). These results indicate that pomegranate peels of Jordanian origin are rich in phytochemical content and exhibited strong antioxidant and antimicrobial activities making these agroindustrial by-products potential candidates for various medical applications and possible safe sources for important bioactive components.

Sorbus Aucuparia L. Fruit Extract and its Cosmetics – As Promising Agents for Prophylactic and Treatment of Pyodermitis: Phytochemical and Microbiological Research

Background: The problem of acne is relevant. The market mostly represents synthesized substances for prevention and treatment, but medical cosmetics based on plant-origin raw material, especially fruits, can be offered. The fruits of Sorbus aucuparia L. are rich in biologically active substances, which turned out to be unique in solving problems of acne. Objective: The aim of the research was to study the phenolic composition and microbiological activity of the S. aucuparia fruit extract and the proposed medicinal cosmetics to prove the possibility of their use for the treatment of pyodermitis. Methods: The phenolic compounds of the S. aucuparia fruit extract obtained with 70% ethanol solution were studied by HPLC. The microbiological research was carried out by methods of diffusion into agar. Results: In the S. aucuparia extract gallic acid, gallocatechin, epigallocatechin, catechin, epicatechin, epicatechin gallate, ellagic acid, hyperoside, rutin, quercetin-3-D-glucoside, chlorogenic, caffeic, ferulic and р-coumaric acids, umbelliferone were identified and quantified. The antimicrobial activity of the S. aucuparia extract has been established. The synergism of antimicrobial activity of 1/4 and 1/64 minimal suppression concentration erythromycin against all tested Staphylococci strains was manifested by the extract. Biological active substances of S. aucuparia fruits more effectively restore sensitivity to erythromycin in Staphylococci with low macrolide resistance of Staphylococci (MLS-resistance) due to blocking reflex mechanisms. Conclusion: The S. aucuparia fruit extracts are rich in phenolic compounds and show antimicrobial activity against all used test-strains of microorganisms. The results of the study indicate their high antimicrobial activity against the main pathogens of pyodermitis - S. aureus, S. epidermidis, and Propionibacterium acnes.

Addition of Silver Nanoparticles to Composite Edible Films and Coatings to Enhance Their Antimicrobial Activity and Application to Cherry Preservation.

The aim of this study was to examine the potential enhancement of the antimicrobial activity of edible films, composed of (i) chitosan (CH), cellulose nanocrystals (CNC) and beta-cyclodextrin (CD) (50%-37.5%-12.5%) and (ii) hydroxypropyl methylcellulose (HPMC), cellulose nanocrystals (CNC) and beta-cyclodextrin (CD) (50%-37.5%-12.5%), with silver nanoparticle (AgNP) incorporationat levels 5, 10 and 15% v/v. According to the results, the AgNP addition led to very high antimicrobial activity of both films, reducing by more than 96% the microbial growth of the Gram-negative bacterium Escherichia coli (E. coli) in all cases. On the other hand, by adding AgNPs to films, their thickness as well as oxygen and water vapor permeability decreased, while their transparency increased. Furthermore, the contribution of these specific edible films to preserve cherries under cold storage was investigated. All edible coatings resulted in an improvement of the fruit properties under consideration, and especially the color difference, hardness and total microbial load.

Advancements in Enhancing Antibacterial Properties of Cotton Fabric through Chitosan and Nanoparticles

AbstractOver recent years, the garment industry has been actively seeking innovative solutions to address critical challenges in clothing production. One significant issue has been the susceptibility of hydrophilic cotton fabrics, commonly used in healthcare and sportswear, to bacterial growth, posing hygiene concerns. To deal with this, it becomes crucial for us to make durable cotton fabrics that can fight bacteria. This study explores the development of durable antibacterial cotton textiles by utilizing a range of antibacterial agents and mechanisms. Chitosan's properties, such as its ability to inhibit fungal growth, compatibility, non‐toxicity, bioactivity, and antimicrobial potential make it a promising candidate for the textile industry. Additionally, the incorporation of metal nanoparticles along with chitosan offers interesting potential, such as UV absorption, self‐cleaning capabilities, and antimicrobial activity. Therefore, research aimed at enhancing cotton fabric by harnessing the potential of chitosan and metal nanoparticles continues to attract significant attention in today's textile world. Cotton fabric modified by combining chitosan and nanoparticles exhibits high antimicrobial activity compared to fabric modified with either nanoparticles or chitosan alone. The implications of this study are far‐reaching with improvement in hygiene, comfort, and durability in a wide range of clothing applications, thus making a substantial contribution to the evolution of the textile industry.

Structural and antibacterial evaluation of copper, silver, and bimetallic silver/copper nanoalloys synthesized in chitosan biopolymer

Silver nanoparticles (AgNP) have been used as an alternative to microbial resistance. Nevertheless, AgNP high cost and moderate toxicity to humans limit their use. Copper nanoparticles (CuNP) emerge as an alternative, but their fast oxidation hampers large-scale use. In this scenario, this work propose the synthesis optimization of Ag, Cu, and bimetallic Ag/Cu nanoparticles in a chitosan aqueous solution using factorial design statistics. UV-Vis spectroscopy, zetasizer, and transmission electron microscopy (TEM) measurements demonstrated that the optimized synthetic procedure formed highly stable and monodisperse nanoparticles. X-ray diffraction (XRD) confirmed the nanoparticle's crystalline structure and indicated the presence of an oxide state in CuNP. In addition, X-ray photoelectron spectroscopy (XPS) measurements confirmed that this oxidation occurs at the CuNP surface level. Considering Ag/CuNP, Rietveld refinement of XRD diffractogram demonstrates the formation of an unusual and novel Ag/Cu nanoalloy structure, which was possible due to the metallic ion chelation to chitosan nitrogens before and during nanoparticle growth. In addition, silver presence in the nanoalloy inhibited copper oxidation through an electromigration mechanism. Comparing CuNP, AgNP, and Ag/CuNP, it was possible to reveal the microbicide abilities of the nanoparticles against both Gram-positive and Gram-negative bacteria, emphasizing that the Ag/Cu nanoalloy is a viable option due its high antimicrobial activity and colloidal stability. Therefore, the rational design allowed the synthesis of highly stable NP in the chitosan matrix which exhibited strong antimicrobial activity, indicating that Ag/Cu nanoalloys can act as the next-generation nanomaterials for pathogenic microorganism inactivation.

Phenolic content, antioxidant and antimicrobial activities evaluation and relationship of commercial spices in the lebanese market

Lebanese cuisine is renowned for its distinctive flavours and vibrant aromas. In Lebanese cuisine, spices are not just used for their flavour; they are also valued for their medicinal properties. This study consists of evaluating and comparing the total phenolic content and the antioxidant capacity of 21 samples of spices used in the Lebanese daily diet, such as cinnamon, allspice, coriander, cloves, etc. and the mixtures prepared in well-defined proportions. Several solvents were tested for the extraction of the phenolic compounds from spices, and the water and ethanol (v/v) mixture were retained for this study. Results showed that clove presented the highest polyphenol content (173.7 ± 2.98 mg Gallic Acid Equivalent (GAE)/g Dry Matter (DM)) and the highest antioxidant capacity by ABTS test (4875.68 ± 480.40 µmol trolox / g DM). and DPPH test (85.84 ± 0.5%). The examination of the results showed a positive significant correlation between the polyphenol contents and the antioxidant activity of the spices. The antimicrobial activity tested by the broth microdilution method was determined against Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella Enteritidis. The results showed high antimicrobial activity manifested by low value of minimum inhibitory concentration (MIC) (MIC < 2.4 µg/mL) for cinnamon, turmeric, white pepper, red pepper, allspice, clove and nutmeg. In conclusion, spices used in Lebanese cuisine, such as clove, cinnamon, allspice and spices, were rich in phenolic compounds and presented important potential health benefits.

In vitro activity of ceftazidime-avibactam, imipenem-relebactam, aztreonam-avibactam, and comparators toward carbapenem-resistant and hypervirulent Klebsiella pneumoniae isolates.

To our knowledge, this is the first study to report the in vitro activity of two novel antimicrobial drugs, including imipenem-relebactam (IMR) and aztreonam-avibactam (AZA), toward carbapenem-resistant and hypervirulent Klebsiella pneumoniae (CR-hvKP) strains. Our in vitro activity study revealed that only few antibacterial agents (including several novel agents) exhibit high antimicrobial activity toward carbapenem-resistant Klebsiella pneumoniae (CRKP) and CR-hvKP isolates. IMR and AZA may be promising therapeutic agents for the treatment of infections caused by CRKP and CR-hvKP isolates.

Antibacterial Activity of Rainbow Trout Plasma: In Vitro Assays and Proteomic Analysis.

The objective of this study was to investigate the bactericidal activity of blood plasma from cultured rainbow trout obtained from two different fish farms. Plasma from trout naturally infected with the bacterial pathogen Flavobacterium psychrophilum was found to inhibit the growth of Aeromonas hydrophila in vitro. Incubation of A. hydrophila in bacteriostatic trout plasma resulted in agglutination and growth retardation, without causing massive damage to the cell membrane. The proteome of the plasma with high antimicrobial activity revealed an abundance of high-density apolipoproteins, some isoforms of immunoglobulins, complement components C1q and C4, coagulation factors, lectins, periostin, and hemoglobin. Analysis of trout proteins retained on A. hydrophila cells revealed the presence of fish immunoglobulins, lectins, and complement components on bacteria whose growth was inhibited, although the native membrane attack complex of immunised trout plasma did not assemble effectively, resulting in a weak bactericidal effect. Furthermore, this study examined the bacterial response to trout plasma and suggested that the protein synthesis pathway was the target of antimicrobial proteins from fish blood. Taken together, these findings illustrate the advantages of the affinity approach for understanding the role of plasma proteins in host defence against pathogens.