Strong Antibacterial Activity Research Articles

Synthesis of novel Fe3O4@gly@Indole@CuNO3 magnetic nanoparticle as high-performance antibiotic absorbent, antimicrobial agent, and reusable magnetic Nano catalyst

The synthesis of nanoparticles has gained attention for their broad applications. Our research focused on developing a novel material, Fe3O4@gly@Indole (FGI), and exploring its diverse uses. FGI was synthesized in two steps using FeCl2.4H2O, FeCl3.6H2O, glycine, and indole-3-carboxaldehyde. Its structure was confirmed via FT-IR, XRD, VSM, SEM, TGA, and EDAX. Antimicrobial tests revealed FGI exhibited higher activity than some antibiotics, with a Minimum Inhibitory Concentration (MIC) of 1µg/mL against Staphylococcus aureus. To enhance its properties, a magnetic nanocatalyst (FGICu) was synthesized by combining FGI with Cu(NO3)2. FGICu proved effective in synthesizing chromeno[4,3-b]chromen-6-one derivatives, achieving 95% yield in 20minutes at 50°C. Additionally, FGICu outperformed FGI in antibacterial tests, showing a lower MIC of 0.5µg/mL and stronger bactericidal activity (MBC of 2-8µg/mL). FGICu also demonstrated significant potential as an adsorbent, with a maximum adsorption capacity of 500.8mg/g for tetracycline (TC). The adsorption mechanism involved electrostatic interactions, hydrogen bonding, and π-π stacking, with the SIPS model best fitting the isotherm and pseudo-second-order model describing the kinetics. FGICu maintained over 70% efficiency after five adsorption cycles, showing excellent stability and reusability. These findings suggest FGICu is a promising material for antimicrobial applications and pollutant removal from wastewater.

Multi-functional polysaccharides composite film containing cashew and jik leaf carbon dots: Properties and bioactivities

Carbon dots (CDs) from the leaf powders of cashew (C-CDs), jik (J-CDs) and the mixed cashew/jik (1:1) (CJ-CDs) using hydrothermal method were synthesized and characterized. All three CDs were incorporated into chitosan/starch composite (CS) film at the level of 3 % (w/w). Microstructure images revealed that all films had slight differences in surface and internal structure. Thickness of the CS film increased with the inclusion of fillers (CDs). Inclusion of CDs slightly reduced the tensile and water vapor barrier properties of the CS film. CS film containing C-CDs exhibited the improved elasticity, UV barrier and antioxidant activity among all the films tested. Color and opaqueness of the resulting films were governed by the yellowish CDs. Distinctive peaks of resulting CS film were detected in FTIR spectra, while all CDs had no marked effect on the spectra. The release of CDs from films was more pronounced in water than in alcoholic solutions (10–95 % ethanol). Strongest antibacterial activities against Listeria monocytogenes and Escherichia coli were recorded for CDs added film, in which the highest activities were found for CS/CJ-CDs film. Thermal stability was also enhanced in CS/CJ-CDs film. Thus, the CS film loaded with CDs, especially from the mixture of cashew and jik leaf powders could serve as a promising active packaging for inactivation of some pathogens in food products.

Antibacterial activity of cell-free supernatant produced by Lactobacillus coryniformis 7841 against Vibrio parahaemolyticus and its potential application in salmon preservation

In this study, a strain of lactic acid bacteria, whose cell-free supernatant (CFS) exhibited strong antibacterial activity against Vibrio parahaemolyticus, was isolated from traditional Chinese fermented vegetables and identified as Lactobacillus coryniformis 7841 (LC7841) based on morphological, biochemical, and molecular characteristics. The minimum bactericidal concentration and minimum inhibitory concentration of the 10-fold cell-free supernatant concentrate (CFSC) were both 10 μL/mL against V. parahaemolyticus. CFSC caused cell wall and membrane disruption of V. parahaemolyticus validated by the increasing leakages of intracellular substances (nucleic acids, proteins, and β-galactosidase), alkaline phosphatase and the accumulation of malondialdehyde. In further, scanning electron microscopy, transmission electron microscopy, and live-dead cell observation by confocal laser scanning microscope revealed that CFSC caused cell wall and membrane damages in V. parahaemolyticus in a concentration-dependent manner. The composite films incorporating CFSC in chitosan-gelatin based films were applied for salmon preservation. The composite films significantly inhibited the propagation of V. parahaemolyticus, decreased the decay rate, and prolonged the shelf-life of salmon. Consequently, these results indicated that CFC of LC7841 may have potential applications as biopreservatives against Vibrio-related contamination in seafood.

Cost-effective synthesis of zinc oxide/crab shell-derived chitosan nanocomposite: Insights into its biomedical applications.

For biomedical applications, material scientists all over the world are working to develop cost-effective technologies and thereby synthesize new nanocomposite materials that are biocompatible, bioactive, scalable and naturally abundant. This study focuses on synthesizing and evaluating nanocomposites of zinc oxide (ZnO) and chitosan (CS) derived from crab shells, in three different weight proportions (1:0.5, 1:1, and 1:2). ZnO/CS nanocomposites were synthesized using a soft-chemical method. Characterization of the nanocomposites was done using XRD, FESEM, EDAX, FTIR, and PL techniques. Among the three formulations, the ZnO/CS nanocomposite with a 1:2 ratio (ZnO/CS1:2) exhibited the most significant antioxidant, anti-diabetic, and antibacterial properties. The (ZnO/CS)1:2 demonstrated 89.46 and 90.85 % of inhibition in DPPH and superoxide free radical scavenging assays, respectively, and showed 91.86 % inhibition of alpha-glucosidase enzyme. It also exhibited strong antibacterial activity against both gram-positive (Staphylococcus epidermidis, Bacillus subtilis) and gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Additionally, the cytotoxicity of the (ZnO/CS)1:2 nanocomposite was assessed against the MCF-7 breast cancer cell line, showing an IC50 value of 11.58 ± 0.05 μg/mL at 30 μg/mL. The ZnO/CS (1:2) nanocomposite shows potential as a candidate for biomedical applications, particularly in antioxidant, anti-diabetic, antibacterial, and cytotoxicity activities.

Development and characterization of antibacterial marine extract-infused cellulose acetate nanofibers as wound dressings for combatting multidrug-resistant wound infections

Wound infections caused by multidrug-resistant bacteria pose a significant challenge globally in healthcare. Traditional wound dressings often lack efficacy against these resilient pathogens, necessitating the exploration of innovative approaches to combat infections and promote wound healing. This study was designed to investigate a novel wound dressing marine extract-infused electrospun cellulose acetate nanofibers (CANF) with particular emphasis on combating multidrug-resistant bacteria. Cellulose acetate (CA) solution was blended with marine extract (Heteroxenia Fuscescens soft coral, H. Fu) before the formation of electrospun nanofibers. The antibacterial activities of H. Fu extract and the prepared nanofiber mats were explored against Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, and Staphylococcus epidermidis. Results displayed that H. Fu extract has a robust antibacterial action against tested bacteria. Different concentrations of H. Fu (0.05 g, 0.1 g, 0.2 g, and 0.3 g) were added to CA solutions, and named as H. Fu-1@CANF, H. Fu-2@CANF, H. Fu-3@CANF and H. Fu-4@CANF, respectively. The obtained results from SEM analysis demonstrated the smooth and uniform fibers. As observed, the results also domenstrated that the addition of H. Fu with specific concentrations (0.05 g, 0.1 g, 0.2 g) has no significant impact on the smooth properties of the formed nanofibers. Increasing the concentration of H. Fu (0.3 g) leads to the formation of nanofibers coated with huge beads. The contact angle values of CANF, H. Fu-1@CANF, H. Fu-2@CANF, and H. Fu-3@CANF were 33.3°, 57.1°, 60.8° and 62.9°, respectively. The prepared nanofiber samples were tested for their inhibitory impact on bacterial survival counts using the disc diffusion method. Important results from the study include the observation that H. Fu-3@CANF exhibited the largest zones of inhibition (ZOI) with diameters of 35 ± 0.25 mm for P. aeruginosa, 32 ± 0.65 mm for A. baumannii, 28 ± 0.14 mm for S. aureus, and 27.6 ± 0.48 mm for S. epidermidis. Additionally, the H. Fu-2@CANF sample demonstrated strong antibacterial activity, with ZOI diameters of 32 ± 0.56 mm, 29 ± 0.81 mm, 26 ± 0.27 mm, and 25.4 ± 0.28 mm for the respective bacteria. The Microtox® assay further evaluated the toxicity levels of the nanofiber mats, revealing that while all samples exhibited some toxicity, the H. Fu-3@CANF sample had the lowest toxicity profile. These findings highlight the potential of H. Fu-loaded nanofibers, particularly H. Fu-3@CANF, for broad-spectrum antibacterial applications. The study underscores the importance of incorporating bioactive compounds into nanofiber mats to enhance their antimicrobial properties, making them suitable candidates for medical and environmental applications requiring effective bacterial eradication.

A Combined Computational and Experimental Approach to TiO2 Nanoparticles: Tailoring Structural, Optical, Antibacterial, And Dielectric Properties

This study explored the structural, optical, antibacterial, and dielectric properties of TiO2 nanoparticles synthesized using two distinct approaches: sol-gel and biosynthesis. Density functional tight binding (DFTB+) and density functional theory (DFT) calculations were employed alongside experimental techniques to gain a comprehensive understanding of the electronic-property relationships. Allium sativum peel extract was utilized for the biosynthesis method. X-ray diffraction (XRD) affirmed the anatase phase formation for both nanoparticles. Rietveld technique was employed for a detailed structural analysis. The biosynthesized nanoparticles exhibited smaller particle sizes (26.74 nm) with a narrower size distribution (15-35 nm) than the sol-gel variant (32.22 nm, 25-45 nm). Optical studies showed an absorption redshift for the biosynthesized variant (352 nm) relative to the sol-gel variant (347 nm). The band gap energy is higher for the sol-gel variant (3.17 eV) compared to the biosynthesized variant (3.02 eV). The biosynthesized nanoparticles showed strong antibacterial activity, with inhibition zones of 15 mm against E. coli and S. flexneri bacteria. Dielectric analysis revealed a higher dielectric permittivity (27.80) and lower dielectric loss (0.37) for the sol-gel synthesized nanoparticles at 1 kHz compared to the biosynthesized nanoparticles (19.48, 0.69).

A dissolving microneedle patch loaded with plumbagin/hydroxypropyl-β-cyclodextrin inclusion complex for infected wound healing

Treating infected wounds is facing a serious challenge due to the rapid spread of antibiotic resistance worldwide. In the search for novel antimicrobial drugs, natural products often serve as a crucial resource. Plumbagin (PLB) is the most important natural active ingredient in the root of Plumbago zeylanica L. known for its excellent antibacterial ability. However, the application of PLB is limited because of its poor water solubility, instability, and tendency to sublimate. In this study, we propose a solution by designing a hyaluronic acid (HA)/polyvinylpyrrolidone (PVP) dissolving microneedle patch loaded with PLB/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex. PLB was encapsulated into the cavity of HP-β-CD to improve its solubility and stability using the neutralization agitation method. The formation of the inclusion complex significantly increased the water solubility of PLB to 1350 ± 6.8 μg/mL, which is 17 times higher than its original value of 79.3 ± 1.7 μg/mL. The encapsulation efficiency was found to be 94.82 ± 3.34%. In vitro drug release studies, PLB microneedles loaded with PLB/HP-β-CD inclusion complex rapidly released into PBS within 15min. Furthermore, the PLB microneedles exhibited strong antibacterial activity against Staphylococcus aureus (S. aureus) both in vivo and in vitro. They also remarkably accelerated the healing of infected wounds in mice by enhancing collagen deposition and re-epithelialization, reducing inflammation, and stimulating angiogenesis. Overall, this multifunctional microneedle patch shows promising potential for clinical applications in the healing of infected wounds.

Genomic Features and Antimicrobial Activity of Phaeobacter inhibens Strains from Marine Biofilms.

Members of the genus Phaeobacter are widely distributed in the marine environment and are known for their ability to produce tropodithietic acid (TDA). Studies investigating the genomic and metabolic features of Phaeobacter strains from marine biofilms are sparse. Here, we analyze the complete genomes of 18 Phaeobacter strains isolated from biofilms on subtidal stones, with the aim of determining their potential to synthesize secondary metabolites. Based on whole-genome comparison and average nucleotide identity calculation, the isolated bacteria are classified as novel strains of Phaeobacter inhibens. Further analysis reveals a total of 153 biosynthetic gene clusters, which are assigned to 32 gene cluster families with low similarity to previously published ones. Complete TDA clusters are identified in 14 of the 18 strains, while in the other 4 strains the TDA clusters are rather incomplete and scattered across different chromosome and plasmid locations. Phylogenetic analysis suggests that their presence or absence may be potentially attributed to horizontal gene transfer. High-performance liquid chromatography-mass spectrometry analysis demonstrates the production of TDA in all the examined strains. Furthermore, the Phaeobacter strains have strong antibacterial activity against the pathogenic strain Vibrio owensii ems001, which is associated with acute hepatopancreatic necrosis in South American white shrimp. Altogether, this study ameliorates our knowledge of marine biofilm-associated Phaeobacter and offers new avenues for exploiting marine antimicrobial agents.

Naturally derived 3-aminoquinuclidine salts as new promising therapeutic agents

Quaternary ammonium compounds (QACs) are a biologically active group of chemicals with a wide range of different applications. Due to their strong antibacterial properties and broad spectrum of activity, they are commonly used as ingredients in antiseptics and disinfectants. In recent years, the spread of bacterial resistance to QACs, exacerbated by the spread of infectious diseases, has seriously threatened public health and endangered human lives. Recent trends in this field have suggested the development of a new generation of QACs, in parallel with the study of bacterial resistance mechanisms. In this work, we present a new series of quaternary 3-substituted quinuclidine compounds that exhibit potent activity across clinically relevant bacterial strains. Most of the derivatives had minimal inhibitory concentrations (MICs) in the low single-digit micromolar range. Notably, QApCl and QApBr were selected for further investigation due to their strong antibacterial activity and low toxicity to human cells along with their minimal potential to induce bacterial resistance. These compounds were also able to inhibit the formation of bacterial biofilms more effectively than commercial standard, eradicating the bacterial population within just 15 min of treatment. The candidates employ a membranolytic mode of action, which, in combination with the generation of reactive oxygen species (ROS), destabilizes the bacterial membrane. This treatment results in a loss of cell volume and alterations in surface morphology, ultimately leading to bacterial cell death. The prominent antibacterial potential of quaternary 3-aminoquinuclidines, as exemplified by QApCl and QApBr, paves the way for new trends in the development of novel generation of QACs.

Ag enhanced CuS nanoflower catalyst coupling dielectric barrier discharge plasma for disinfection performance and mechanism

In this study, the hydrothermal method was employed to grow submicron CuS on carbon cloth (CC), and the photoreduction method was used to grow Ag nanoparticles on the CuS submicron flowers, thus forming the Ag/CuS/CC catalytic electrode. The application of Ag/CuS/CC electrode-coupled dielectric barrier discharge (DBD) plasma in the disinfection of pathogenic bacteria in water was studied. The Ag/CuS/CC electrode exhibits strong antibacterial activity, and under an external voltage of 30 V, the degradation efficiency of Bacillus subtilis reaches 99.99% within 15 min without regeneration. After five cycles, the inactivation rate of Bacillus subtilis reached 99.99% within 25 min. The practical applicability of the Ag/CuS/CC-coupled DBD system for treating actual wastewater was evaluated, and the changes in biological toxicity were investigated. The results indicate that the prepared Ag/CuS/CC coupled DBD has great potential for safe disinfection of pathogenic bacteria in water through integrated processes.

Propolis-loaded photocurable methacrylated pullulan films: Evaluation of mechanical, antibacterial, biocompatibility, wound healing and pro-angiogenic abilities

The ultimate goal of this study was to establish the groundwork for the development of high-mechanical pullulan based films for wound healing applications. For this purpose, pullulan (PUL) was successfully methacrylated with different methacrylic anhydride amounts and used for the fabrication of photocurable wound dressing films (PULMA). The mechanical properties of the films, evaluated by changing the methacrylation degree and polymer concentration for better mechanical performance, indicated the best results in terms of elastic modulus (2.55 ± 0.15 MPa), tensile strength (2.48 ± 0.12 MPa), and elongation at break (848 ± 111 %). Additionally, the incorporation of PRO into wound dressing films has demonstrated strong antibacterial activity against Escherichia coli and Staphylococcus aureus, and it has also improved the release profile. The obtained films have scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH). The wound dressing films were not cytotoxic to NIH/3T3 cells, a fibroblast cell line, according to the cytotoxicity assay. The in vitro scratch test showed that PRO incorporated films induced cell migration, suggesting that they have the potential to close wounds and promote healing. According to the image analysis conducted following the in ovo chorioallantoic membrane (CAM) test, PRO inclusion boosted different angiogenesis parameters stemming from the films. Clear evidence has been found that PRO loaded into high mechanical performance PUL based films can be suitable for advanced wound dressing applications.

Novel antibacterial pullulan derivatives modified with quaternary phosphonium salts for infected wound treatments

The development of novel antibacterial agents is urgently needed to tackle bacterial infection, the major global issue menacing human health. Among them, polymeric quaternary phosphonium salts are worth noticing owing to their strong antibacterial activities and other merits including low bacterial drug resistance. Herein, pullulan modified with quaternary phosphonium salts (PQP) was synthesized using esterification reactions of pullulan and (5-carboxypentyl)triphenylphosphonium bromide (CPTPPB) mediated by N,N′‑carbonyldiimidazole (CDI), and was evaluated as novel antibacterial agents for treating wound infection for the first time. The chemical structures, chemical bonding, elemental compositions, crystalline properties and thermostability of PQP were systematically investigated. PQP exhibited in vitro antibacterial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), which were unveiled by the spread plate method and possibly resulted from the damage of bacterial cell walls/membranes mediated by electrostatic and hydrophobic interactions according to preliminary mechanism studies. Weak cytotoxicity and excellent hemocompatibility of PQP at the effective bactericidal concentration were observed. Moreover, in the infected wound model of mice, PQP was capable of disinfecting the wound and accelerating the healing. We opine PQP in this work is promising for antibacterial applications and will inspire the synthesis of novel antibacterial agents derived from natural polymers.

Omiganan-Based Synthetic Antimicrobial Peptides for the Healthcare of Infectious Endophthalmitis.

Bacterial endophthalmitis is a severe infection of the aqueous or vitreous humor of the eye that can lead to permanent vision loss. Due to the rapid emergence of antibiotic resistance and dose-limiting toxicities, the standard treatment of bacterial endophthalmitis via the intravitreal injection of broad-spectrum antibiotics remains inadequate. Membrane active cationic antimicrobial peptides (AMPs) have emerged as a promising class of effective and broad-spectrum antimicrobial agents with potential to overcome antibiotic resistance. In this work, we investigate, for the first time, the use of omiganan (IK-12), a 12-amino acid indolicidin derivative for the treatment of bacterial endophthalmitis. Additionally, IK-12 was used as a template to perform amino acid rearrangements, without altering the length or type of amino acids, to yield a series of new derivative AMPs with varying extents of secondary structure formation under membrane mimicking conditions. IK-12 and its derivatives demonstrated strong and broad-spectrum antibacterial activities against a panel of clinically isolated Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus commonly implicated in bacterial endophthalmitis. Interestingly, two of the new IK-12 derivatives, IP-12 and WP-12, showed lower geometric mean minimum inhibitory concentration and higher 50% hemolysis concentration values, which effectively translated into 2- to 3.4-fold higher bacterial selectivity than the parent IK-12. Furthermore, the intravitreal injection of IK-12, IP-12, and WP-12 in a rabbit model of MRSA-induced endophthalmitis led to considerably improved clinical presentation and reduced recruitment of inflammatory cells. In all, these results demonstrate the potential of IK-12 and its derivatives, IP-12 and WP-12, as promising candidates for the treatment of bacterial endophthalmitis.

Diversity and Anti-Infectious Components of Cultivable Rhizosphere Fungi Derived from Three Species of Astragalus Plants in Northwestern Yunnan, China.

Astragalus, a group of legume plants, has a pronounced rhizosphere effect. Many species of Astragalus with limited resource reserves are distributed in the high-altitude area of northern Yunnan, China. Although some of these plants have high medicinal value, the recognition of them is still at a low level. The aim of this research is to explore the species diversity of cultivable rhizofungi derived from Astragalus acaulis, A. forrestii and A. ernestii growing in a special high-cold environment of northwest Yunnan and discover anti-infective components from these fungi. A total of 93 fungal strains belonging to 38 species in 18 genera were isolated and identified. Antibacterial and antimalarial screening yielded 10 target strains. Among them, the ethyl acetate crude extract of the fermented substrate of the rhizofungus Aspergillus calidoustus AA12 derived from the plant A. acaulis showed broad-spectrum antibacterial activity and the best antimalarial activity. Further chemical investigation led to the first discovery of seven compounds from the species A. calidoustus, including sesterterpine 6-epi-ophiobolin G; three sesquiterpenes, penicisochroman A, pergillin and 7-methyl-2-(1-methylethylethlidene)-furo [3,2-H]isoquinoline-3-one; and three polyketides, trypacidin, 1,2-seco-trypacidin and questin. Among them, the compound 6-epi-ophiobolin G exhibited moderate to strong antibacterial activity against six Gram-positive pathogens with the minimum inhibitory concentration (MIC) ranging from 25 to 6.25 μg/mL and a prominent inhibitory effect on the biofilm of Streptococcus agalactiae at an MIC value of 3.125 μg/mL. This compound also displayed potent antimalarial activity against Plasmodium falciparum strains 3D7 and chloroquine-resistant Dd2 at the half-maximal inhibitory concentration (IC50) values of 3.319 and 4.340 µmol/L at 72 h, respectively. This study contributed to our understanding of the cultivable rhizofungi from characteristic Astragalus plants in special high-cold environments and further increased the library of fungi available for natural anti-infectious product screening.

Correlation analysis between phytochemical composition and biological activities of Artemisiascoparia

As a homologous plant of medicine and food, Artemisia scoparia has rich nutritional value and medicinal components. The main contents are to analyze the phytochemical composition and various biological activities of A. scoparia, and to explore the Pearson correlation between the contents of each phytochemical composition and biological activities. The ethanol extract (EA) and its fractions (n-hexane extract (NHE), ethyl acetate extract (EAC), n-butanol extract (NBA), and water extract (HO)) of A. scoparia were rich in polyphenols, polysaccharides, terpenoids, coumarins, flavonoids and showed potential for antibacterial, antioxidant, hypoglycemic, lipid-lowering, and anti-inflammatory activities. EAC contains the highest amount of coumarins and flavonoids, shows strong antibacterial, antioxidant, hypoglycemic, lipid-lowering and anti-inflammatory (COX-2) activities. In addition, the inhibition rate of NHE on LOX was higher, and Pearson correlation reveled a strong association between phytochemical composition and biological activities: Coumarins had antimicrobial properties, flavonoids had antioxidant and hypoglycemic effects, and flavonoids and terpenoids had anti-inflammatory effects. There was a significant negative correlation between coumarins and MBC of S. aureus (r = 0.84, p < 0.001) and C. albicans (r = 0.84, p < 0.001). Flavonoids (r = 0.86, p < 0.001) showed a significant negative correlation with α-glucosidase scavenging ability. Terpenoids also showed a significantly negative correlation with LOX scavenging ability (r = 0.70, p < 0.001). A comprehensive understanding of both physiological functionalities and potential applications related to the bioactive elements present in extracts from A. scoparia could potentially provide valuable scientific insights to guide its medical or health-related utilization.

Bimetallic FeCo metal–organic framework based cascade reaction system: Enhanced peroxidase activity for antibacterial performance

Metal-organic frameworks (MOFs), as a peroxidase (POD), can catalyze the conversion of H2O2 to reactive oxygen species (ROS) for antibacterial application. To achieve strong antibacterial activity, it is necessary to improve the enzyme-like activity of MOFs. In this study, FexCoMOF was synthesized by incorporating Co(II) to improve the electron transfer of Fe(III)/Fe(II), which enhanced its redox capacity as a nanozyme and further promoted the generation of hydroxyl radical (⋅OH), exhibiting higher POD activity. Doping with different amounts of Co(II) altered the particle size, specific surface area, and surface defects of FexCoMOF, thus exhibiting differential enzyme-like activities. Additionally, a glucose-responsive enzyme cascade reaction system based on Fe4CoMOF/glucose oxidase (GOx) was established. In the presence of glucose, the in situ-generated substrate H2O2 was in contact with the catalytic site and the generated gluconic acid enabled Fe4CoMOF to maintain maximum enzyme activity under physiological pH conditions, avoiding damage caused by the use of exogenous high concentrations of H2O2. In the in vitro antibacterial experiment, the minimum inhibitory concentration (MIC) of Fe4CoMOF/GOx was 10 μg mL−1 for Escherichia coli (E. coli) and 5 μg mL−1 for Staphylococcus aureus (S. aureus) (∼108 CFU mL−1). The increase in enzyme activity resulted in a considerable reduction in the dose of the antibacterial agent, which was conducive to improving bio-safety. The in vivo experiment in mice demonstrated that the glucose-responsive Fe4CoMOF-based cascade reaction system had excellent antibacterial properties and remarkably promoted wound healing. The antibacterial agent based on bimetallic MOF developed in this work provides a new idea for cascade catalytic antibacterial therapy and will have remarkable application prospects in biomaterials and nanomedicine.

Therapeutic Potential of Insect Defensin DLP4 Against Staphylococcus hyicus-Infected Piglet Exudative Epidermitis.

Background/Objectives: The emergence of resistance to Staphylococcus hyicus (S. hyicus), the major cause of exudative epidermatitis (EE) in piglets, has led to the need for new antimicrobial agents. The study aimed to evaluate the potential efficacy of the insect defensin DLP4 against EE in piglets caused by clinically isolated S. hyicus ACCC 61734. Methods and Results: DLP4 showed strong antibacterial activity against S. hyicus ACCC 61734 (minimum inhibitory concentration, MIC: 0.92 μM, median effect concentration, EC50: 3.158 μM). DLP4 could effectively inhibit the formation of S. hyicus early biofilm with an inhibition rate of 95.10-98.34% and eradicate mature biofilm with a clearance rate of 82.09-86.41%, which was significantly superior to that of ceftriaxone sodium (CRO). Meanwhile, DLP4 could efficiently inhibit bacteria in early and mature biofilm, killing up to 95.3% of bacteria in early biofilm and 87.2-90.3% of bacteria in mature biofilm. The results showed that DLP4 could be effective in alleviating the clinical symptoms of EE by down-regulating the nuclear factor κB (NF-κB) signaling pathway, balancing cytokines, inhibiting bacterial proliferation, and reducing organ tissue damage. Conclusions: This study firstly demonstrated the potential efficacy of DLP4 against EE caused by S. hyicus ACCC 61734 infection in piglets, which may be used as an alternative to antibiotics in treating EE.

Broad-spectrum antimicrobial activities of a food fermentate of Aspergillus oryzae.

The development of NP, a potent broad-spectrum antimicrobial, is a significant breakthrough in the ongoing challenge against microbial foodborne illnesses and the growing threat of antibiotic resistance. This food-grade culture broth of Aspergillus oryzae demonstrates exceptional broad-spectrum efficacy against a variety of harmful bacteria and fungi, including drug-resistant strains such as methicillin-resistant Staphylococcus aureus and prevalent food spoilage molds. NP exhibits strong bactericidal activity against various foodborne and ESKAPE pathogens, and strong antifungal activity against Penicillium species, Aspergillus fumigatus, and Candida albicans. The potent bactericidal and antifungal properties of NP are a result of its ability to disrupt microbial cell membranes leading to increased permeability. Furthermore, the genome-wide impact of NP on fungal gene expression and metabolic pathways underscores its comprehensive antimicrobial action, leading to transcriptomic and metabolic changes associated with cell death in A. fumigatus.

Multifunctional nanomaterials composed entirely of active pharmaceutical ingredients for synergistically enhanced antitumor and antibacterial effects.

Multifunctional nanomaterials are emerging as promising tools for treating both cancer and bacterial infections. However, integrating dual therapeutic capabilities into a single system remains challenging. This study presents multifunctional nanoparticles (ECI-NPs) based on Epigallocatechin gallate (EGCG) oligomers, Curcumin (CUR), and Indocyanine Green (ICG) for combined cancer and bacterial treatment. ECI-NPs were synthesized via oxidative coupling of EGCG, CUR, and ICG. The nanoparticles were characterized for stability, size, drug loading, and release profiles. Cellular uptake, phototoxicity in melanoma cells, and antibacterial activity against Escherichia coli and Staphylococcus aureus were also evaluated. ECI-NPs demonstrated optimal stability, high drug loading, and controlled release. Cellular studies showed increased uptake and greater phototoxicity in melanoma cells compared to free drugs. ECI-NPs also exhibited enhanced anticancer effects and strong antibacterial activity, outperforming the individual components. The polyphenol-based ECI-NPs offer synergistic therapeutic effects, overcoming the limitations of free drugs in terms of solubility and efficacy. This dual-function platform shows potential for broader biomedical applications, addressing challenges in cancer and bacterial infections. Further research will focus on in vivo studies and clinical translation.

Penicitrisochromans A-C, new isochromans from the marine-derived fungus Penicillium citrinum PSU-MF100.

Three new isochroman derivatives, penicitrisochromans A-C (1-3), together with 25 known polyketides were isolated from the marine-derived fungus Penicillium citrinum PSU-MF100. Their structures were elucidated by extensive spectroscopic analysis. The absolute configurations of 1 and 2 were established by comparison of specific rotations and electronic circular dichroism (ECD) data with those of the known co-metabolite whereas those of 3 were assigned based on the ECD calculation and biosynthetic consideration. Among the isolated polyketides, three known anthraquinone derivatives, ω-hydroxyemodin, penicillanthranin A and emodin, displayed moderate to strong antibacterial activity against methicillin-resistant Staphylococcus aureus with MIC values of 32, 16 and 4 µg/mL, respectively. For antifungal activity, two known benzopyranones, coniochaetones A and C, exhibited moderate antifungal activity against Candida albicans NCPF3153 and Cryptococcus neoformans ATCC90112 with the respective MIC values of 16 and 64 µg/mL.