Search Results (1,495)

Dental erosion has emerged as a significant modern oral health problem, characterized by the chemical dissolution of tooth structure resulting from frequent exposure to intrinsic or extrinsic acids. With a high global prevalence ranging from 30% to 50% in children and 20% to 40% in adults, its management is a clinical priority to prevent long-term complications like dentine hypersensitivity and functional impairment. This review outlines the multifactorial etiology of erosion, encompassing dietary acids, gastroesophageal reflux, and reduced salivary flow. The historical context of oral care is explored, leading to a discussion on contemporary management strategies centered on remineralization. Fluoride ions play a crucial role by inhibiting demineralization, facilitating the formation of acid-resistant fluorapatite, and exerting antibacterial effects. A major focus is placed on advanced biomimetic, calcium phosphate-based topical agents such as Casein Phosphopeptide–Amorphous Calcium Phosphate (CPP-ACP), functionalized Tricalcium Phosphate (fTCP), and Hydroxyapatite (HAP), which effectively replenish lost minerals. The review further explores innovative methods, such as laser-assisted and electrically enhanced remineralization. Finally, it outlines next-generation regenerative strategies, including self-assembling peptides (P11-4), stem cell therapies, 3D bioprinting, and gene-editing (CRISPR) technologies, which aim to biologically regenerate lost enamel and dentine. The field is rapidly evolving from a preventive to a restorative paradigm, with future directions focusing on biologically based, minimally invasive therapies to fully restore tooth structure and function. Full article

Bovine mastitis is a major bioeconomic and animal health challenge in dairy systems and is traditionally managed with intensive antibiotic therapy, contributing to antimicrobial resistance (AMR). This study explored the therapeutic potential of essential oils (EOs) from two native species of the Valdivian temperate rainforest, Laureliopsis philippiana (Tepa; LP_EO) and Drimys winteri (Canelo; DW_EO), against priority mastitis pathogens. Gas Chromatography–Mass Spectrometry (GC–MS) was used to characterize EO composition, and in vitro antibacterial and antifungal activities were evaluated against clinical isolates of Staphylococcus aureus, Streptococcus uberis and the azole-resistant yeast Pichia kudriavzevii by disk diffusion and broth microdilution assays. Both EOs were dominated by monoterpenes; LP_EO was richer in oxygenated monoterpenes (eucalyptol, terpinen-4-ol), whereas DW_EO showed a pinene-rich profile (β-pinene, α-pinene). DW_EO produced significantly larger inhibition zones than LP_EO against S. aureus and P. kudriavzevii and exhibited lower MIC₅₀/MIC₉₀ values for S. aureus, S. uberis and P. kudriavzevii. Notably, DW_EO showed a higher inhibitory activity against P. kudriavzevii with a MIC₉₀ of 4 mg/mL. These findings support DW_EO as a high-potential dual-action phytotherapeutic candidate for developing formulations and complementary tools within sustainable bovine udder health and antimicrobial stewardship frameworks. Full article

Background/Objectives: Multidrug resistance (MDR) remains a critical global public health concern, compromising the efficacy of currently available antibiotics. As the development of new antibiotics offers limited long-term solutions, alternative approaches such as efflux pump inhibition have gained attention. This study reports the development of nanostructured lipid carriers (NLCs) co-loaded with Norfloxacin (NOR) and the efflux pump inhibitor 2-amino-thiophen-6CN-Ethyl, to modulate NOR activity against resistant Staphylococcus aureus strains overexpressing efflux pump genes. Methods: NLCs were produced via the hot emulsion method followed by sonication. The formulations were characterized for encapsulation efficiency (EE%), particle size, polydispersity index (PDI), zeta potential, X-ray diffraction (XRD), infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), in vitro release kinetics, and stability. Antibacterial activity was evaluated against S. aureus 1199B and K2068 strains. Results: The NLC formulation containing norfloxacin and 6CN-Ethyl (NLC10NOR + 106CN) demonstrated high EE% for both compounds (99.50% for 6CN-Ethyl and 90.91% for NOR) and physicochemical stability over 60 days (particle size < 255 nm, PDI < 0.3, zeta potential < −20 mV). Structural analyses confirmed amorphization and effective encapsulation of the active constituents. Antibacterial assays showed that NLC10NOR + 106CN significantly increased NOR activity compared to the free drug and physical mixture; the effect in 1199B was notably superior to the NOR + CCCP (carbonyl cyanide m-chlorophenylhydrazone) combination. Conclusions: These findings highlight the potential of NLC-based co-delivery systems as innovative strategies to overcome bacterial resistance, particularly through efflux pump inhibition enhancing antibiotic efficacy. Full article

The global crisis concerning multidrug-resistant microorganisms necessitates the development of innovative antimicrobial strategies that avoid conventional antibiotics and overcome the toxicity and environmental persistence associated with traditional metal-based biocides. This work aims to develop safe and sustainable antibacterial filtration materials by integrating cationic hyperbranched polymer dendrimers (HBP) into electrospun nanofibers. Cationic HBPs were successfully embedded into recycled polyamide 6 nanofibers using industrial needleless electrospinning. Filtration efficiency, assessed against a 0.3 µm paraffin oil aerosol according to EN 149:2001, consistently exceeded 99.8%, meeting and surpassing the FFP3 classification threshold while maintaining low air resistance. The HBP-functionalized nanofibers exhibited pronounced contact-active antibacterial activity against Staphylococcus aureus and Escherichia coli. Quantitative plate count assays confirmed viability reductions of up to 74.1% after 2 h of co-incubation. Crucially, the absence of inhibition zones in agar diffusion tests confirmed that the active polymer was stably embedded within the nanofiber matrix and did not leach. Comprehensive toxicological tests, including cell line and 3D human skin and airway tissue models, confirmed the material’s safety for both dermal and respiratory contact. This study presents a scalable, metal-free, and environmentally responsible next-generation filtration system that combines high mechanical efficiency with active antimicrobial functionality. Full article

In this study, a silver-based metal–organic framework (Ag-MOF) nanozyme was synthesized for the synergistic eradication of drug-resistant Salmonella enteritidis in food matrices. Ag-MOF exhibits multiple enzyme-like activities, namely oxidase (OXD)-, peroxidase (POD)-, and superoxide dismutase (SOD)-like activities. It demonstrated excellent antibacterial and antibiofilm activities against erythromycin- and chloramphenicol-resistant S. enteritidis strains (N29 and P23). Specifically, treatment with 20 mg mL⁻¹ Ag-MOF resulted in nearly complete eradication of S. enteritidis in in vitro suspension assays, including 1 × 10⁷ CFU mL⁻¹ N29 strain and 6 × 10⁶ CFU mL⁻¹ P23 strain. Moreover, treatment with 1 mg mL⁻¹ Ag-MOF led to 80~90% biofilm inhibition of S. enteritidis. Mechanistic investigations revealed that Ag-MOF effectively interacted with amino-rich structures on the bacterial surface (such as membrane proteins and peptidoglycan components), generated abundant reactive oxygen species (ROS), released Ag⁺ ions, and depleted intracellular glutathione, which collectively disrupted cell membrane integrity and induced severe leakage of intracellular proteins and nucleic acids. Importantly, Ag-MOF maintained high antibacterial efficacy in complex simulated food matrices (pork, milk, and egg shell). Overall, this study offers key insights into enzyme-mimicking antibacterial materials and a promising strategy to combat multidrug resistant foodborne pathogens. Full article

The escalating challenge of antimicrobial resistance has spurred interest in probiotics as alternatives for combating bacterial infections. This study aimed to isolate and characterize probiotic Lactobacillus johnsonii (L. johnsonii) from yak feces with protective efficacy against acute Escherichia coli (E. coli) infection. In vitro, DY2 supernatant inhibited the growth of E. coli. In vivo, mice pretreated orally with DY2 (1 × 10⁹ CFU/mL) for 21 days before E. coli challenge exhibited significantly reduced weight loss (p < 0.001), lower bacterial translocation in the intestines (p < 0.001), and normalized organ indices (p < 0.05) compared to untreated infected controls. DY2 modulated host immune and oxidative responses by significantly lowering serum levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6; p < 0.001 to p < 0.05) and malondialdehyde (MDA; p < 0.001), while elevating levels of the anti-inflammatory IL-10 (p < 0.05) and antioxidant enzymes (SOD, GSH-Px, T-AOC; p < 0.001 to p < 0.01). Histologically, DY2 preserved intestinal mucosal integrity, with reduced villus shortening and inflammatory infiltration (p < 0.001 for villus length in key segments). 16S rRNA sequencing of intestinal microbiota revealed enhanced α-diversity (p < 0.05 to p < 0.001), community stability, and enrichment of beneficial genera such as Butyricimonas in DY2-treated mice. Conclusively, Lactobacillus johnsonii DY2 protects against acute E. coli infection via anti-inflammatory, antioxidant, gut barrier strengthening, and microbiota-modulating activities. Yak-derived lactobacilli are promising probiotics with excellent antibacterial properties. Full article

Due to the indiscriminate use of antimicrobial drugs in the treatment of infectious diseases, human pathogenic bacteria have developed resistance to many commercially available antibiotics. Medicinal plants such as Convolvulus arvensis represent a renewable resource for the development of alternative therapeutic agents. This study aimed to evaluate the antibacterial activity of silver nanoparticles (AgNPs) biosynthesized from C. arvensis against two clinical antibiotic-resistant bacterial isolates. The pathogenic isolates were identified as Staphylococcus aureus MRSA and Escherichia coli ESBL using 16S rRNA gene sequencing. Silver nanoparticles were synthesized via a green synthesis approach, and their physicochemical properties were characterized using UV–Vis spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, zeta potential, and dynamic light scattering (DLS). The synthesized C. arvensis–AgNPs exhibited a surface plasmon resonance peak at 475 nm and predominantly spherical morphology with particle sizes ranging from 102.34 to 210.82 nm. FTIR analysis indicated the presence of O–H, C–O, C–N, C–H, and amide functional groups. The nanoparticles showed a zeta potential of −18.9 mV and an average hydrodynamic diameter of 63 nm. The antibacterial activity of the biosynthesized AgNPs was evaluated against methicillin-resistant S. aureus (MRSA and ATCC 29213) and E. coli (ESBL and ATCC 25922) using agar diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Inhibition zones ranged from 10 to 13 mm, with MIC and MBC values of 12.5–25 µg/mL and 25–50 µg/mL, respectively. In addition, the nanoparticles exhibited antioxidant activity (DPPH assay, IC₅₀ = 0.71 mg/mL) and anti-inflammatory effects as determined by protein denaturation inhibition. No cytotoxic effects were observed in the MCF-7 cell line at the MIC level. These findings suggest that C. arvensis–AgNPs have potential as natural antimicrobial, antioxidant, and anti-inflammatory agents. Full article

The antibacterial activity of 18 phenolic compounds, including flavonoids and phenolic acids, against organisms of Escherichia coli, Klebsiella pneumoniae, and Proteus vulgaris that are resistant to several drugs was assessed in this study using the agar diffusion method. The strain’s strong resistance was confirmed by antibiotic susceptibility testing, which used fourteen drugs and only found inhibition zones for five of them. Out of the polyphenols, four compounds were effective against P. vulgaris, five against K. pneumoniae, and twelve against E. coli bacteria. The greatest inhibitory zone (18.75 ± 0.25 mm) against E. coli was shown by propyl gallate, an ester of gallic acid. Activity was significantly impacted by structural changes. Propyl substitution increased antibacterial activities across all strains, while methoxy substitution decreased them. The antibacterial effectiveness was reduced by the hydroxylation of flavonoids and the C3–C4 dihydroxylation of cinnamic acid. Propyl gallate primarily had antagonistic effects, while combination experiments demonstrated additive, synergistic, and antagonistic interactions. Propyl gallate (ΔG = −7.5 kcal/mol) exhibited substantial binding affinities with TEM-1 and NDM-1 β-lactamases via hydrogen and hydrophobic interactions, according to molecular docking. These results demonstrate propyl gallate as a viable antibacterial adjuvant option and validate the structure–activity relationship of phenolic compounds. Full article

Background/Objectives: Epilepsy is characterized by unpredictable seizures and drug resistance, along with rising antimicrobial resistance (AMR), highlighting the urgent need for innovative dual-action therapies. This study aimed to design, develop, and evaluate novel pyrazolone derivatives for a dual antimicrobial and antiepileptic potential. Methods: Novel pyrazolone derivatives were designed, synthesized (using 2,4-dinitrophenylhydrazine/semicarbazide condensation with ethyl acetoacetate), and evaluated through molecular docking against antimicrobial (4URM, 3FYV, 3FRA) and neuronal targets (4COF, 5TP9, 5L1F). The in vitro antimicrobial activity was assessed against Gram-positive (S. aureus) and in vitro Gram-negative (E. coli, P. aeruginosa) strains via agar cup plate assays, while in vivo antiepileptic efficacy was tested in a PTZ-induced seizure model in Swiss albino mice. Results: Compound IIa showed potent dual activity, inhibiting E. coli (9 mm zone at 80 μg/mL) and S. aureus (9.5 mm at 80 μg/mL), alongside a significantly delayed seizure onset in the PTZ-induced mouse model (100% survival rate, 45 sec delayed seizure onset, p < 0.001). Compounds Ia and Id showed selective activity against E. coli (6 mm at 80 μg/mL) and P. aeruginosa (7 mm at 80 μg/mL), respectively. Docking studies revealed that compound IIa has a superior binding affinity (−7.57 kcal/mol for 3FYV) compared to standards, driven by hydrogen bonds (SER X: 49) and hydrophobic interactions (LEU X: 20). Conclusions: This study presents a novel approach by proposing a rationally designed pyrazolone scaffold exhibiting both antimicrobial and antiepileptic activity, which integrates in silico modeling with experimental validation. Compound IIa emerged with preliminary dual biological activities, exhibiting strong antibacterial activity, a superior binding affinity toward both bacterial and neuronal targets, and notable seizure prevention in vivo. These findings show the potential of multifunctional pyrazolone derivatives as a new treatment strategy for addressing drug-resistant infections linked to epilepsy and support further optimization toward clinical development. Full article

The escalating threat of antibiotic resistance, particularly from Staphylococcus aureus (S. aureus), has become a critical challenge in both public health and animal husbandry. The extensive use of conventional antibiotics in livestock production accelerates the emergence of resistant strains, heightening risks to food safety and human health. Although plant-derived bioactive compounds are increasingly recognized as promising alternatives to synthetic antimicrobials, the mechanisms underlying their efficacy—and the potential for synergistic action among different plant parts—remain poorly understood. In particular, the antibacterial interactions among extracts from different tissues of Cyperus esculentus L. (C. esculentus), a plant rich in flavonoids and phenolics, have yet to be systematically evaluated. Here, we investigated the antibacterial properties and mechanisms of ethanol extracts from the tubers, stems–leaves and their mixture of C. esculentus against S. aureus. Using Oxford cup diffusion assays, scanning electron microscopy (SEM), bacterial growth kinetics, and untargeted metabolomics, we assessed both phenotypic inhibition and metabolic disruption. The mixed extract exhibited the strongest antibacterial effect, producing a 26.15 mm inhibition zone—approximately 7% greater than that of single-part extracts—and induced cell wall rupture and disintegration as observed by SEM. Growth curve analyses revealed time-dependent bacterial suppression, while metabolomic profiling identified 845 differential metabolites, indicating disturbances in amino acid, lipid, and nucleotide metabolism. Flavonoids such as acacetin, diosmetin, naringenin, and silybin A were identified as principal active compounds contributing to these effects. Full article

Background: The current rise in multidrug-resistant pathogens highlights the urgent need for the discovery of novel antibacterial agents with potential clinical applications. A considerable proportion of these developed resistances may be attributable to the intrinsic response of bacteria to antibiotic-induced stress conditions in the environment. Consequently, the identification and characterization of genetic alterations in physiological processes in response to antibiotics represent promising strategies for the discovery and characterization of naturally produced novel antibacterial agents. This study investigated the antimicrobial activity of an antimicrobial active isolate Actinomadura coerulea derived from a meerkat fecal sample. Methods: The production of secondary metabolites that potentially compromise bacterial cell wall integrity was confirmed by the induction of promoter activity in whole-cell biosensors in which an antibiotic-inducible promoter was fused to the luciferase cassette. During plate-based biosensor assays, we identified naturally resistant Bacillus subtilis colonies growing in the zone of inhibition around A. coerulea colonies. After these successive rounds of selection, highly resistant spontaneous B. subtilis mutants had evolved that were subjected to whole-genome sequencing. Results: Non-silent mutations were identified in pssA, which encodes a phosphatidylserine synthase; mdtR, as a gene for the repressor of multidrug resistance proteins, and yhbD, whose function is still unknown. A new cinnamycin-like molecule, coerumycin, was discovered based on the physiological role of PssA and comprehensive genomic analysis of A. coerulea. Additional experiments with cell extracts containing coerumycin as well as the cinnamycin-like compound duramycin confirmed that the interaction between coerumycin and the bacterial cell envelope is inhibited by a loss-of-function mutation in pssA. Conclusion: Our approach demonstrates that combining the exploration of niche habitats for actinomycetes with whole-cell biosensor screening and characterization of natural resistance development provides a promising strategy for identifying novel antibiotics. Full article

Background/Objectives: The rise in antimicrobial resistance is one of the major challenges to global health systems, which necessitates the development of new antibacterial compounds. The bioactive compounds of brown seaweed Sargassum duplicatum have demonstrated potential antibacterial activity. This study applied metabolomic profiling and molecular networking in combination with antibacterial screening assays to assess the antimicrobial properties of S. duplicatum extracts against multidrug-resistant bacteria. Methods: Two extraction methods, i.e., maceration and microwave extraction, were used. Therewith, untargeted metabolomic profiling was performed using Liquid Chromatography–High Resolution Mass Spectrometry (LC-HRMS). Molecular networks (MNs) were established and compound dereplication was conducted using the spectral database of the Global Natural Products Social Molecular Networking platform (GNPS). Additionally, antimicrobial assays were conducted against Gram-positive and Gram-negative bacterial strains, including multidrug-resistant bacteria, i.e., methicillin-resistant Staphyloccocus aureus ATCC 33592 (MRSA) and β-lactamase, producing Escherichia coli ATCC 35218 (TEM-1 positive strain). Result: Dereplication resulted in the prediction of six compounds with reported antimicrobial properties, i.e., 13-docosenamide, 9-octadecenamide, pheophorbide A, ouabain, sarmentoside B and AC1L1X1Z. Antibacterial screening of the extracts revealed that the ethyl acetate maceration extracts exhibited the strongest inhibitory activity, with inhibition values between 85 and 98% against S. aureus ATCC 33592. Conclusions: This metabolomics study requires further research to isolate, purify, confirm, and validate the dereplicated compounds that may have potential antibacterial activity. Full article

Antimicrobial resistance (AMR) is a major global health concern, which complicates treatment of microbial infections and wounds. Conventional therapies are no longer effective against drug resistant microbes; hence, novel antimicrobial approaches are urgently required. Silver nanoparticles (AgNPs) offer stronger antimicrobial activity, and in situ synthesis improves stability, uniformity, cost efficiency, and bioactivity while minimising contamination. These features make AgNPs well-suited for incorporation into textiles and wound dressings. Red wine extract (RW-E), rich in antioxidant and anti-inflammatory compounds was used to hydrothermally synthesise RW-AgNPs and RW-AgNPs-loaded on cotton (RWALC) by optimising pH and RW-E concentration. Characterisation was performed using UV–Vis spectroscopy, dynamic light scattering (DLS), and High Resolution and Scanning electron microscopy (HR-TEM and SEM). Antibacterial activities were evaluated against human pathogens through agar disc diffusion assay for RWALC and microdilution assay for RW-AgNPs. RWALC showed higher potency against both Gram-negative and Gram-positive bacteria, with inhibition zones of 12.33 ± 1.15 to 23.5 ± 5.15 mm, that surpassed those of ciprofloxacin (10 ± 3 to 19.17 ± 1.39 mm at 10 μg/mL). RW-AgNPs exhibited low minimum inhibitory concentrations (MIC: 0.195–3.125 μg/mL) and minimum bactericidal concentrations (MBC: 0.78–6.25 μg/mL). Preincubation with β-mercaptoethanol (β-ME) inhibited the antibacterial activity of RWALC, suggesting that thiolated molecules are involved in AgNPs-mediated effects. This study demonstrated that green-synthesised RW-AgNPs, incorporated in situ into cotton, conferred strong antibacterial properties, warranting further investigation into their mechanisms of action. Full article

Silver nanoparticles (AgNPs) possess distinct physicochemical characteristics and demonstrate high antibacterial potential that highlights them as promising alternatives against a wide range of pathogens. The immense antibacterial potential of AgNPs is primarily attributed to the release of silver ions that lead to the disruption of bacterial cell membrane, generation of reactive oxygen species (ROS), inhibition of protein synthesis and interference with DNA replication. Variations in AgNPs’ shape, size, and surface characteristics are also considered key factors determining their effectivity as well as specificity. AgNPs are considered potent antibacterial agents, including against antibiotic- and drug-resistant strains. However, inappropriate dosages or unoptimized application of may result in potential toxicity, consisting one of the main drawbacks of the AgNPs’ safer administration. This article reviews the recent literature on the antibacterial potential of AgNPs, focusing on their broad mechanisms of action, applicability, especially in agriculture, biomedical and environmental fields, toxicity and future perspectives. Full article

The misuse of antibacterial agents has contributed to the growing prevalence of antibiotic resistance, highlighting an urgent need to explore alternative anti-infection therapeutic strategies. Antimicrobial peptides (AMPs) are naturally occurring molecules. They exhibit broad-spectrum antimicrobial activity and represent promising candidates for the development of novel therapeutics. A cysteine-rich antimicrobial peptide was identified and characterized from the genome of Tigriopus japonicus and designated “TjRcys1”. The precursor form of TjRcys1 comprises 96 amino acids. Structural analyses of TjRcys1 revealed random coils, two α-helices, and two β-strands. Recombinant TjRcys1 had inhibitory effects upon Staphylococcus aureus and Bacillus sp. T2, with a minimum inhibitory concentration of 64 μM for both. TjRcys1 did not show complete inhibition against Vibrio alginolyticus, Klebsiella pneumoniae, or Aeromonas hydrophila at 64 μM, but it did slow their growth rate. TjRcys1 could disrupt the permeability of the cell membrane of S. aureus. Transcriptomic analyses indicated that TjRcys1 could interfere with the ribosome biosynthesis and nucleotide metabolism of K. pneumoniae. Our results provide a valuable reference for the development of new AMPs and optimization of their design. Full article