Effective Antibacterial Activity Research Articles

Antibacterial Activity and Mechanism of Rose Essential Oil against Aeromonas veronii isolated from Northern snakehead (Channa argus).

To investigate and identify the antibacterial action and mechanism of rose essential oil (REO) against Aeromonas veronii isolated from northern snakehead for the first time by the phenotypic and metabolic analysis. The two-fold broth microdilution and spread-plate method identified that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of REO against A. veronii were 1.25 μL mL-1 and REO impaired the growth in a concentration-dependent manner, indicating that REO possessed a significant bacteriostatic activity. Electron microscopy and live-dead cell staining found that REO caused a severe disruption of cellular morphology and increased the membrane permeability. Additionally, REO treatment induced the leakage of intracellular biomolecules such as proteins and nucleic acids from the bacteria. Metabolomics analysis showed that compared with the control, the REO treatment group exhibited a total of 190 differential metabolites (118 down-regulated and 72 up-regulated), which involved in the main metabolic pathways such as biotin metabolism, arginine biosynthesis, glutathione metabolism, lysine degradation, and histidine metabolism and the TCA cycle. These results verified that REO disturbed the metabolic processes of A. veronii to achieve the bacteriostatic effect. The REO exhibited the effective antibacterial activity against A. veronii via breaking the cellular structure, increasing the membrane permeation and disrupting the metabolic processes.

Antibacterial Activity Of Staphylococcus aureus From Chinese Betel Leaf Juice (Peperomia pellucida L.)

Infectious diseases, especially in developing countries such as Indonesia, are a common health problem, one of which is caused by bacteria. This study tested the antibacterial activity of Chinese betel leaf extract against Staphylococcus aureus bacteria, with secondary metabolite content such as alkaloids, tannins, and flavonoids that act as antibacterials. This study was a laboratory experiment using a completely randomized design with three repetitions at five concentrations of extract, as well as one positive and negative control. The method used was the agar diffusion method, and the test results showed that Chinese betel leaf extract had antibacterial potential against Staphylococcus aureus at various concentrations tested. The concentrations used were 6µL/disc, 8µL/disc, 10µL/disc, 12µL/disc, and 14µL/disc, where all these categories produced inhibition zones included in the moderate category according to Susanto (2012). Statistical analysis using the Kruskal-Wallis test produced a significant value of 0.035 (<0.05), indicating a significant difference between each concentration tested. From the research results, it can be concluded that Chinese betel leaf extract has effective antibacterial activity against Staphylococcus aureus.

Liposome/chitosan coating film bioplastic packaging for Litchi fruit preservation

Chitosan is an ideal coating film for food preservation, but the performance of a single chitosan coating film is not good. Herein, the liposome was prepared by embedding copper nanoparticles (CuNPs) and thyme essential oil (TEO) in the hydrophilic and hydrophobic double-domain structure formed by phospholipids, and combining with chitosan to obtain a chitosan-based coating film for litchi preservation. The liposome was well-dispersed and stable with an average particle size of about 190 nm. The liposome showed excellent controllable release properties, and the cumulative release rate of TEO was 65.17 % and that of CuNPs was 15.17 % after 7 days. Furthermore, the oxygen and water vapor barrier properties of the coating film were greatly improved. Importantly, the film possessed effective antioxidant, antibacterial activity and excellent safety, which presents a better fresh-keeping effect on litchi. This study provides insights into the design and manufacture of food packaging for controllable and long-lasting preservation.

Green synthesis of multifunctional responsive hydrogel embedded with silver, based on xanthan gum, N-isopropylacrylamide, vinyl imidazole, and Luffa cylindrica for wound healing

In this study, a pH- and temperature-responsive smart hydrogel was developed by utilizing Xanthan Gum (XG), N-Isopropylacrylamide (NIPAM), Vinyl Imidazole (VI), and Luffa cylindrical (LC). Semi-interpenetrating polymer networks (semi-IPNs) were created using free radical polymerization with N,N′-methylenebisacrylamide (MBA) as the cross-linker and ammonium persulfate (APS) as the initiator. Silver nanoparticles (AgNPs) were synthesized within semi-IPN hydrogel network structures to impart antibacterial properties. Malva sylvestris (MS) aqueous leaf extract was used as a reducing and stabilizing agent for the green synthesis of the AgNPs. The semi-IPN hydrogels exhibited pH- and temperature-responsive swelling behavior, which also enabled the controlled release of the drug. After 11 h, the cumulative release reached approximately 73% at pH 7.2 and 87% at pH 8.3. Additionally, the sustained release mechanism of the Trimethoprim drug was described using the Korsmeyer-Peppas model and was governed by Fickian diffusion. The drug-loaded semi-IPN@Ag nanocomposite hydrogel has demonstrated effective antibacterial activity against various Gram-negative and Gram-positive bacteria, indicating its promising potential as a wound dressing material for reducing infection risk.

Synthesis, spectral characterization and biological activities of o,o'-dihydroxyazo compounds containing gallic acid: Molecular docking and dynamics simulation and MM-PBSA studies

In the investigation, diazonium derivatives of 2-aminophenol, 2-amino-4-methylphenol, 2-amino-4-chlorophenol, and 2-amino-5-nitrophenol reacted with gallic acid to produce four distinct o,o'-dihydroxyazo compounds. Description of the o,o'-dihydroxyazo compounds that were produced identified the substituent spectrum data using UV–Vis, FT-IR, NMR spectroscopy and MS spectrometry methods. The UV–Vis behaviors of compounds in ethanol and DMSO were noted at various pH values. The antioxidant, antimicrobial, and urease inhibitory activities of the compounds were determined spectrophotometrically and compared to standard compounds. The DPPH˙ scavenging and metal chelating activities of compound 4b were 2.17 ± 0.04 and 11.62 ± 0.64 μg/mL, respectively. Compounds exhibited an effective antibacterial activity against B. cereus. The urease inhibition capacity of compound 4c (IC50: 4.79 ± 0.01 μg/mL) was more effective than thiourea (IC50: 20.04 ± 0.16 μg/mL). Moreover, molecular docking calculations were used to assess the urease inhibition potentials, inhibition kinetics, and interactions of the synthesized compounds with antimicrobial enzymes and urease. The compounds had substantial impacts on density functional theory (DFT), molecular electrostatic potential (MEP), inhibition kinetics, enzyme inhibition, and PASS prediction tests. For this reason, molecular dynamics simulation and MM-PBSA energy calculation were performed to assess the compounds' stability during urease binding.As a result, the effective pharmacological properties of the newly synthesized o,o'-dihydroxyazo compounds were revealed by different in vitro bioactivity tests and in silico calculations.

FengycinA-M3 Inhibits Listeria monocytogenes by Binding to Penicillin-Binding Protein 2B Targets to Disrupt Cell Structure.

The contamination of food with Listeria monocytogenes threatens food safety and human health, and developing a novel, green, and safe antimicrobial substance will offer a new food preservation strategy. FengycinA-M3 is a novel lipid peptide with low cytotoxicity and resistance and has effective antibacterial activity against L. monocytogenes with a minimum inhibitory concentration (MIC) of 4 µg/mL. Further combined transcriptomics and proteomics analysis yielded 20 differentially expressed genes (DEGs). The MICs of the combined use of FengycinA-M3 and Cefalexin on L. monocytogenes were further determined as FengycinA-M3 (2 µg/mL) and Cefalexin (8 µg/mL) using the checkerboard method. In addition, FengycinA-M3 was found to play a role in delaying pork deterioration. This study explored the inhibitory effect of FengycinA-M3 on L. monocytogenes and its mechanism of action. FengycinA-M3 interacted with penicillin-binding protein 2B on the cell membrane of L. monocytogenes, destroying the permeability of the membrane, causing cell membrane rupture, thereby inhibiting the growth of L. monocytogenes. Overall, FengycinA-M3 is a promising candidate for preventing the emergence and spread of L. monocytogenes with potential applications in food processing.

Fabrication of highly flexible biopolymeric chitosan/agarose based bioscaffold with Matricaria recutita herbal extract for antimicrobial wound dressing applications

A flexible biopolymer-based antimicrobial wound dressing has the potential to alleviate the burden of bacterial infections in wounds by enhancing antimicrobial effectiveness and promoting faster wound healing. This study focuses on the development of a highly flexible chitosan-agarose (CS-AG) bioscaffold, incorporating Matricaria recutita chamomile flower extract (CH) through a conventional casting method. The flexible CS-AG bioscaffold's physiochemical properties were confirmed by FTIR, indicating secondary interactions, and XRD, showing its crystalline structure. The addition of CH to the optimized CS-AG bioscaffold resulted in significant tensile strength (17.28 ± 0.33 MPa), distinctive structural morphology (SEM), surface roughness (AFM), contact angle, improved thermal properties (DSC), and enhanced thermal stability (TGA). Furthermore, the CH-infused bioscaffold significantly increased swelling capacity (~81.09 ± 1.74 % over 48 h), and degradation profile (~52 % over 180 h). The release studies of CS-AG-CH bioscaffold demonstrate controlled release of CH with in the bioscaffold at different pH conditions. The bioscaffold demonstrated effective antibacterial activity against S. aureus and E. coli strains. Additionally, cytotoxicity assays indicated that the bioscaffold supports better cell viability and proliferation in fibroblast (NIH 3T3) cell lines. Consequently, this antimicrobial bioscaffold shows promise as a drug release system and biocompatible wound dressing suitable for tissue engineering applications.

Biodegradable antimicrobial films prepared in a continuous way by melt extrusion using plant extracts as effective components

Packaging plays an important role in delaying food spoilage. However, conventional packaging films do not have antimicrobial properties. Films with antimicrobial components are receiving growing research interest. However, many of the reported studies use conventional non-degradable polymers during film preparation, posing a significant threat to the environment and sustainable development. Furthermore, conventional inorganic antibacterial agents are commonly used during film preparation, posing a risk to food safety. In this study, antibacterial compounds were extracted from diverse plants, and then biodegradable antimicrobial films were prepared in a continuous way via the melt extrusion method. Especially, films prepared using Vernicia fordii and Phyllanthus urinaria extracts showed effective antibacterial activities against common foodborne pathogens. This study is the first to prepare antibacterial films in a continuous way using natural plant extracts as the effective components, and may shed new light on future research in preparing green antibacterial films via environment-friendly approaches.

Hydrogels with Essential Oils: Recent Advances in Designs and Applications.

The innovative fusion of essential oils with hydrogel engineering offers an optimistic perspective for the design and development of next-generation materials incorporating natural bioactive compounds. This review provides a comprehensive overview of the latest advances in the use of hydrogels containing essential oils for biomedical, dental, cosmetic, food, food packaging, and restoration of cultural heritage applications. Polymeric sources, methods of obtaining, cross-linking techniques, and functional properties of hydrogels are discussed. The unique characteristics of polymer hydrogels containing bioactive agents are highlighted. These include biocompatibility, nontoxicity, effective antibacterial activity, control of the sustained and prolonged release of active substances, optimal porosity, and outstanding cytocompatibility. Additionally, the specific characteristics and distinctive properties of essential oils are explored, along with their extraction and encapsulation methods. The advantages and disadvantages of these methods are also discussed. We have considered limitations due to volatility, solubility, environmental factors, and stability. The importance of loading essential oils in hydrogels, their stability, and biological activity is analyzed. This review highlights through an in-depth analysis, the recent innovations, challenges, and future prospects of hydrogels encapsulated with essential oils and their potential for multiple applications including biomedicine, dentistry, cosmetics, food, food packaging, and cultural heritage conservation.

Ultrasonic-assisted extraction of polyphenolics from Schrebera swietenioides Roxb.: An optimization using response surface methodology

Schrebera swietenioides Roxb is an important medicinal plant used for the treatment of various diseases by the indigenous communities. However, this plant is still underexplored in the modern scientific era. Specifically, the leaves of the plant are reported to contain various medicinal properties such as antioxidant, antimicrobial, anti-inflammatory, and antipyretic activity. Herewith, the present work demonstrates and optimizes the extraction process usingan ultrasonic system and comopared the results with conventional extraction methods. Optimization was performed by combining first and second-order polynomial designs at different levels using Plackett-Burman and Central-Composite designs. A total of 31 experiments were conducted at different levels, including ultrasonic power (10–40 %), solvent-to-sample ratio (20–50 mL/g), solvent concentration (50–80 %), and HCl normality (0.2–1 N). The findings of the study suggest a significant (p<0.05) influence of extraction parameters on the extraction yield of the response variables, including total phenol (TPC), total flavonoid (TFC), total tannin (TTC), and the antioxidants activity. Further, the predicted values demonstrated good agreement with the experimental values, exhibiting a high (R2>95%) coefficient of determination and a non-significant lack of fit. At the optimized condition, the experimental values of TPC, TFC, TTC and antioxidants (DPPH, ABTS, FRAP) activity were found near the model predicted values. The HPLC-PDA analysis identified ten polyphenolic compounds, among which rutin hydrate (12.991±0.003 mg/g DW), followed by phloridzin (6.660±0.001 mg/g DW), and chlorogenic acid (3.380±0.008 mg/g DW) were the most prominent compounds. Furthermore, the optimized extract showed effective antibacterial activity against Bacillus subtillis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus species. In conclusion, the obtained results indicate that the proposed optimization strategy can be utilized to enhance the yield of polyphenolics from the target species with possibility of its application in therapeutics values.

Synthesis, antimicrobial activity and computational studies on (E)-N-(2((4-chlorobenzylidine)amino)ethyl)napthalen-1-amine

The novel Schiff bases were synthesized by combining N1-(Napthalen-1-yl)ethane 1,2-diamine with chlorine-substituted benzaldehyde. The compound is designated as (E)-N-(2((4-chlorobenzylidine)amino)ethyl)napthalen-1-amine (4CLB). This structure was verified by experimental techniques including infrared, NMR, fluorescence, UV, and theoretical methods. Using the B3LYP functional the titled compound computational study was executed. The results for infrared and NMR analysis of the molecule exhibited a significant degree of agreement in both observed and simulated. The reactivity characteristics of 4CLB were computed. The microbiological efficacy of the compound was assessed against multiple Gram-positive bacteria S. aureus, S pneumonia, and Bacillus subtilis. The compound was tested against the following Gram-negative bacteria: Klebsiella pneumonia, E coli, and Proteus vulgaris. The compound Schiff base exhibits the most effective antibacterial activity against all microbes. The 4CLB compound quantum calculations have a strong correlation with antibacterial activity. The compound has non-covalent Hydrogens, these Hydrogens are bonded with the corresponding proteins. It is checked by molecular docking in the Auto Dock software.

Ultraviolet Protection and Antibacterial Properties of Polylactic Acid Nonwoven Fabrics Coated with Water-Borne Polyurethane/Zinc Oxide Composite Coatings

This study aimed to create thermally curable, water-borne polyurethane/zinc oxide (WPU/ZnO) composite coating pastes with varying ZnO concentrations. ZnO nanoparticles were synthesized using a wet chemical process, and the resulting WPU/ZnO coating pastes were applied to PLA nonwoven fabrics (NWFs). In characterization studies, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform-infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) analyses were conducted. Ultraviolet (UV) protection and antibacterial activity of fabrics were investigated. With WPU/ZnO composite coatings, the UV protection properties of the coated fabrics were enhanced compared to the uncoated fabric. The highest UPF value of 53.57 was obtained with the fabric coated with the formulation containing a ZnO concentration of 10%. This fabric also demonstrated more effective antibacterial activity against both S. aureus and E. coli bacteria. Inhibition zone diameters against E. coli and S. aureus bacteria were measured as 15.5 ± 0.70 mm and 18.25 ± 0.35 mm, respectively. The results of this study illustrate that functional composite coatings for bio-based NWF structures hold great promise for producing effective UV protective and antibacterial materials, potentially setting the stage for future applications.

Chitosan thin films developed with germanium oxide for wound healing applications: Cell viability, wettability, and antibacterial activity

Tailoring a biomaterial with versatile properties is important to develop a multifunctional scaffold for biomedical applications. In this work, chitosan (CS) is chosen to be the matrix material of the scaffold, while hydroxyapatite and germanium dioxide which are encapsulated in CS film enhanced the biological properties. The addition of the dopant increased the hydrophilicity of CS and the chemical reaction on the surface of the scaffold, which supports the adhesion of the scaffold on the skin and cell migration. On the other hand, the TGA showed good thermal stability as about 24.4 % of the scaffold remained at 600 °C. Furthermore, S1 exhibited the most effective antibacterial activity against Bacillus subtilis and Escherichia coli, with an average inhibition zone of 12.5 mm and a low standard deviation of 0.5 mm. S4 demonstrated significant effectiveness against Pseudomonas aeruginosa, with an average inhibition zone of 12.5 ± 0.5 mm. These data indicate that the materials have potential antibacterial capabilities, specifically against Bacillus subtilis and Escherichia coli. Overall, the results indicate that the modified CS scaffold can be utilized in biomedical applications including wound healing.

Tailoring Hydrogel Sheet Properties through Co-Monomer Selection in AMPS Copolymer Macromers.

This study investigates hydrogels based on 2-Acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS) copolymers, incorporating N-hydroxyethyl acrylamide (HEA) and 3-sulfopropyl acrylate potassium salt (SPA). The addition of HEA and SPA is designed to fine-tune the hydrogels' water absorption and mechanical properties, ultimately enhancing their characteristics and expanding their potential for biomedical applications. A copolymer of AMPS, 2-carboxyethyl acrylate (CEA) combined with methacrylic acid (MAA) as poly(AMPS-stat-CEA-stat-MAA, PACM), was preliminarily synthesized. CEA and MAA were modified with allyl glycidyl ether (AGE) through ring-opening, yielding macromers with pendant allyl groups (PACM-AGE). Copolymers poly(AMPS-stat-HEA-stat-CEA-stat-MAA) (PAHCM) and poly(AMPS-stat-SPA-stat-CEA-stat-MAA) (PASCM) were also synthesized and modified with AGE to produce PAHCM-AGE and PASCM-AGE macromers. These copolymers and macromers were characterized by 1H NMR, FT-IR, and GPC, confirming successful synthesis and functionalization. The macromers were then photocrosslinked into hydrogels and evaluated for swelling, water content, and mechanical properties. The results revealed that the PASCM-AGE hydrogels exhibited superior swelling ratios and water retention, achieving equilibrium water content (~92%) within 30 min. While the mechanical properties of HEA and SPA containing hydrogels show significant differences compared to PACM-AGE hydrogel (tensile strength 2.5 MPa, elongation 47%), HEA containing PAHCM-AGE has a higher tensile strength (5.8 MPa) but lower elongation (19%). In contrast, SPA in the PASCM-AGE hydrogels led to both higher tensile strength (3.7 MPa) and greater elongation (92%), allowing for a broader range of hydrogel properties. An initial study on drug delivery behavior was conducted using PACM-AGE hydrogels loaded with photosensitizers, showing effective absorption, release, and antibacterial activity under light exposure. These AMPS-based macromers with HEA and SPA modifications demonstrate enhanced properties, making them promising for wound management and drug delivery applications.

The antibacterial activity test of salt gel face mask with chitosan extract against propionibacterium acnes and staphylococcus aureus bacteria as antiacne preparations

Abstract Salt is a collection of chemical compounds with the main content in the form of NaCl. The mineral content in salt provides health functions for the body, one of which is acne. Salt gel face mask with chitosan extract has the potential to be used as an antibacterial (antiacne) preparation. The purpose of this study was to determine the effective antibacterial activity and concentration of salt used as an antiacne preparation against Propionibacterium acnes and Staphylococcus aureus bacteria in salt gel face masks. The research method used was a laboratory scale experimental method with a completely randomized design (CRD) consisting of 5 treatments and 4 repetitions. The treatment consists of a gel face mask with the addition of a salt concentration of 0%, 10%, 15%, 20% and 25%. The main parameters of this study were antibacterial activity, while the supporting parameters included pH, homogeneity, viscosity, organoleptic and SEM-EDX analysis. The results showed that the addition of different salt concentrations to the salt gel face mask had an effect on the antibacterial activity of the salt gel face mask. The best formulation is in the F4 treatment with a salt concentration of 25%.

QSAR Studies on Thienopyrimidines as Potential Antimicrobial Agents

Background: Recent research has revealed promising antibacterial action for thienopyrimidines. To comprehend the underlying molecular features underlying their antibacterial potency, a thorough quantitative structure-activity relationship (QSAR) investigation is required. Objective: In order to clarify the structural parameters for effective antibacterial activity, we conducted QSAR analyses on a variety of thienopyrimidines in this work. Methods: Through the analysis of physicochemical properties and molecular descriptors, we aimed to develop predictive models that can guide the design of novel thienopyrimidine derivatives with enhanced antimicrobial potential. Results: It was discovered through the descriptor importance analysis that specific physicochemical characteristics, including lipophilicity, electronic distribution, and steric effects, significantly influenced the antibacterial efficacy of these drugs. Conclusion: The identified molecular characteristics and descriptors can be used to guide the development of new thienopyrimidine derivatives with higher antibacterial activity.

Production and Antibacterial Activity of Atypical Siderophore from Pseudomonas sp. QCS59 Recovered from Harpachene schimperi.

Among sixty-eight pseudomonads, isolate QCS59 from the rhizosphere of H. schimperi was selected based on its siderophore level. Production was optimal in Kings B supplemented with 2% peptone and 0.5% fructose at pH 6.5 and 25 °C for 72 h. Additionally, the threshold potential of iron was found at a concentration of 10 µM. After purification, the acidified siderophore presented a maximum absorption peak of 360 nm, while the neutral form presented a maximum of 414 nm, confirming its pyoverdine (PVD) nature. Furthermore, a major peak appeared at a retention time (RT) of 27.5 min during RP-HPLC, confirming its homogeneity. Interestingly, it demonstrated effective antibacterial activity, especially against Escherichia coli ATCC 8739, with a minimum inhibitory concentration (MIC) of 6.3 µg/mL and a minimum bactericidal concentration (MBC) of 12.5 µg/mL. At ½ the MIC value, it inhibited 82.1% of well-established biofilms of Salmonella enterica. There was an increase in malondialdehyde (MDA) and antioxidative enzymes, especially catalase (CAT) in the treated bacteria because of the peroxidation of membrane lipids and oxidative stress, respectively. SEM proved cellular lysis and surface malformation in most of the treated bacteria. This study concludes that QCS59 siderophore is a promising antibacterial candidate for treating wastewater bacteria and skin pathogens.

Green Synthesis of Silver Nanoparticle from Anadenanthera colubrina Extract and Its Antimicrobial Action against ESKAPEE Group Bacteria.

Given the urgent need for novel methods to control the spread of multidrug-resistant microorganisms, this study presents a green synthesis approach to produce silver nanoparticles (AgNPs) using the bark extract from Anadenanthera colubrina (Vell.) Brenan var. colubrina. The methodology included obtaining the extract and characterizing the AgNPs, which revealed antimicrobial activity against MDR bacteria. A. colubrina species is valued in indigenous and traditional medicine for its medicinal properties. Herein, it was employed to synthesize AgNPs with effective antibacterial activity (MIC = 19.53-78.12 μM) against clinical isolates from the ESKAPEE group, known for causing high hospitalization costs and mortality rates. Despite its complexity, AgNP synthesis is an affordable method with minimal environmental impacts and risks. Plant-synthesized AgNPs possess unique characteristics that affect their biological activity and cytotoxicity. In this work, A. colubrina bark extract resulted in the synthesis of nanoparticles measuring 75.62 nm in diameter, with a polydispersity index of 0.17 and an average zeta potential of -29 mV, as well as low toxicity for human erythrocytes, with a CC50 value in the range of 961 μM. This synthesis underscores its innovative potential owing to its low toxicity, suggesting applicability across several areas and paving the way for future research.

Discovery of novel dihydropyrrolidone-thiadiazole compound crosstalk between the YycG/F two-component regulatory pathway and cell membrane homeostasis to combat methicillin-resistant Staphylococcus aureus

The rapid emergence and spread of multidrug-resistant (MDR) Gram-positive pathogens present a significant challenge to global healthcare. Methicillin-resistant Staphylococcus aureus (MRSA) is a particular concern because of its high resistance to most antibiotics. Based on our previously reported chemical structure of compound 62, a series of novel derivatives were synthesized and evaluated for their antibacterial activities. We found that some of these derivatives displayed effective antibacterial activity against Gram-positive pathogens, with minimal cytotoxicity (CC50>100 μM) and hemolytic activity (HC50>200 μM). Among these derivatives, the minimum inhibitory concentration (MIC) of 62-7c against Gram-positive bacterial isolates ranged from 6.25 to 25 μM. This derivative also exhibited significant synergistic antibacterial effects with daptomycin both in vitro and in vivo, with an ability to eradicate planktonic and persister cells of MRSA. Additionally, 62-7c inhibited biofilm formation and eradicated mature biofilms of MRSA. Mechanistic studies revealed that 62-7c inhibited the YycG kinase activity and disrupted the cell membrane by binding to cardiolipin (CL), leading to cell death. Importantly, no development of drug resistance was observed even after 20 serial passages. Furthermore, 62-7c exhibited high biosafety and potent effectiveness in combating infections in both mouse pneumonia and mouse wound models infected with MRSA. Thus, our study revealed that 62-7c has the potential to serve as a novel antibacterial agent for treating MRSA infections.

A shape memory cationized chitosan sponge loaded with thrombin for high-effective hemostasis and antibacterial activity

This study presents a thrombin-loaded cationized chitosan (TCCS) sponge with highly effective hemostatic and antibacterial activity. The TCCS sponge, prepared using a multistep method, features a porous structure, favorable mechanical properties, excellent water absorption ability, and shape recovery triggered by water or blood. The TCCS sponge exhibited strong antibacterial activity against Methicillin-resistant Staphylococcus aureus and Escherichia coli. Additionally, it demonstrated enhanced procoagulant and hemostatic efficacy in rat tail amputation and rat liver perforation wound models compared to commercial hemostats. Furthermore, the sponge exhibited favorable biocompatibility and biosafety. These findings suggest that the TCCS sponge has substantial potential for practical applications in managing severe hemorrhages and bacterial infections.