Search Results (10,797)

Developing advanced bioinspired photoprotective barrier from marine resources represents a critical frontier of bioprocessing. This study established a rational design and implementation of effective photoprotective surface-coating eumelanin from ink of an Indian squid (Uroteuthis duvaucelii). The Central Composite Design was developed to optimize extraction and functionalization parameters of eumelanin on quartz substrates, strategically developing the matrix for peak optical attenuation within the potential Far-UVC window (220 nm). Translational photoprotective efficacy of the surface, as well as finished eumelanin on quartz surface, was validated by subjecting them to a challenging macro-level biological assay using a hospital-grade 254 nm ultraviolet germicidal source (125 µWcm⁻²). Quantitative physical dosimetry established that the squid eumelanin coating (A254 = 1.00) reduced internal transmittance to approximately 10%, successfully dampening the incident fluence from 0.225 J cm⁻² down to a heavily attenuated 0.0225 J cm⁻² at the biological sample plane. While unshielded control indicator microbial strains suffered complete lethal inactivation, the eumelanin barrier maintained exceptional cell viability, yielding biological shielding efficiencies of 98% for Bacillus subtilis, 96% for Staphylococcus aureus, and 92% for Escherichia coli. Characteristic features from FE-SEM, FTIR, and XRD analysis established that this superior photoprotective property is governed by the extensively conjugated, π-π-stacked indolic architecture possessing a characteristic 3.4 Å interlayer d-spacing, which facilitates rapid, non-radiative energy dissipation. This work establishes an effective framework for translating squid biomass into high-value, transparent optical barriers, providing a potential sustainable alternative to synthetic ultraviolet absorbers. Full article

Healthcare-associated infections are prevalent in hospitals, clinics, and long-term care facilities. The use of wound dressings on active skin wounds, like burns, can cause damage to the skin barrier when removed for cleaning. Electrospun biodegradable and biocompatible membranes have emerged as promising alternatives for wound dressing applications. In the present study, an electrospun membrane composed of polyvinyl alcohol/kefiran/schizophyllan loaded with gentamicin and ascorbic acid was developed. Kefiran was obtained from kefir with a 0.61% extraction yield. Beadless electrospun membranes with a diameter of 400 nm were obtained. Antimicrobial activity of the membrane against Staphylococcus aureus and Pseudomonas aeruginosa was determined. Growth inhibition halos of 16.4 ± 2.2 mm were found for Pseudomonas aeruginosa. Furthermore, the membrane cytocompatibility assay of the membrane showed no cell toxicity in human dermal fibroblasts (HDFn cells). The produced membranes showed potential to be used as a wound dressing material in the future. Full article

The escalation of antimicrobial resistance (AMR) represents a serious global threat to public health, with AMR-associated mortality estimated to increase by 70% by 2050. As pathogens evolve through enzymatic inactivation, target modification, efflux-mediated clearance, biofilm formation, and broader genetic adaptation, conventional therapies are increasingly compromised, while the antibiotic development pipeline remains critically constrained by high discovery and development costs, weak commercial incentives, and the escalating complexity of resistance mechanisms. This review comprehensively synthesizes advanced pharmacological and biotechnological innovations designed to circumvent these entrenched resistance mechanisms. We highlight the development of novel therapeutic classes, particularly lariocidin, which disrupts bacterial protein synthesis via a previously unexploited ribosomal-binding site. Moreover, we critically evaluate molecular interventions, emphasizing CRISPR/Cas-based gene silencing and genome editing as precise tools to neutralize specific resistance determinants, such as the mecA gene in methicillin-resistant Staphylococcus aureus (MRSA). Concurrently, we explore the integration of engineered nanoparticles to revitalize existing antimicrobials by overcoming biofilm barriers, improving drug solubility, and enabling targeted delivery. Collectively, mastering the evolving AMR landscape requires a multidimensional framework that seamlessly integrates these novel molecular targets with advanced rapid diagnostics and robust international governance. Full article

Microbiological contamination of surface water represents a critical public health concern, while conventional disinfectants face limitations such as the generation of toxic by-products and the emergence of microbial resistance. In this study, the application of an ethanolic peel extract of Citrus paradisi (grapefruit), obtained by sonication at 40 kHz for 90 min at 55 °C using a 1:4 (w/v) solvent-to-solid ratio, was evaluated as a natural alternative for bacterial reduction in contaminated waters. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extract were first determined against Staphylococcus aureus and Escherichia coli. The extract was then applied to samples of slightly contaminated surface water with bacterial loads between 10³–10⁴ CFU/mL and turbidity of 150 NTU, as well as to highly contaminated surface water with bacterial loads ≥10⁵ CFU/mL and turbidity of 250 NTU. Bacterial removal was assessed at 6, 12, and 24 h. FTIR and UV-Vis characterization of the extract confirmed the presence of flavonoids (naringin), terpenes (limonene), and phenolic compounds. Results showed MIC/MBC values of 2.5/5.0 mg/mL for S. aureus and 5.0/10.0 mg/mL for E. coli. In slightly contaminated water, the extract at 5.0 mg/mL achieved complete (100%) removal of both microorganisms after 12 h, whereas in highly contaminated water, removals ranged from 80–90% for Staphylococcus spp. and E. coli. Statistical analysis (ANOVA, Bonferroni) demonstrated significant differences (p < 0.05) between the extract and ethanol. These findings indicate that Citrus paradisi extract constitutes an effective, sustainable, and low-cost natural alternative for bacterial reduction in surface waters, contributing to the valorization of agro-industrial residues and to the achievement of Sustainable Development Goal (SDG) 6. Full article

Neutrophils are essential for antimicrobial defense through reactive oxygen species (ROS) production, tumor necrosis factor-alpha (TNF-α) release, and neutrophil extracellular trap formation. Lipoic acid, a redox-active antioxidant, modulates activation in human neutrophils. Neutrophils isolated from healthy donors were pretreated with lipoic acid and then exposed to lipopolysaccharide (LPS) or whole Escherichia coli, according to the specific assay. ROS production, NET formation, TNF-α release, bacterial killing, metabolic activity, and cell death were assessed using fluorometric assays, enzyme-linked immunosorbent assay, colony-forming unit assays, MTT reduction, and Annexin V-FITC/propidium iodide flow cytometry. Lipoic acid significantly reduced ROS production and NET formation induced by LPS and Escherichia coli. at 0.5 mM, lipoic acid also reduced E. coli-induced NET formation by approximately 50% and attenuated TNF-α release at early stimulation times. In colony-forming unit assays, lipoic acid did not significantly reduce neutrophil-mediated killing of Escherichia coli or Staphylococcus aureus. Although only neutrophil preparations with high baseline viability were used, Escherichia coli challenge markedly reduced cell viability during the assay; under this condition, lipoic acid pretreatment limited bacteria-induced necrosis and preserved a higher proportion of viable neutrophils. These findings indicate that lipoic acid dampens excessive oxidative and inflammatory neutrophil responses while maintaining measurable bactericidal capacity in vitro. Full article

Mint (Mentha spp.) teas are widely consumed as functional herbal beverages and represent important dietary sources of bioactive volatile compounds. The present study comparatively evaluated the chemical composition and antimicrobial activity of essential oils (EOs) obtained from commercially available Mentha tea products purchased in Estonia, Lithuania, and Norway. In 10 EO samples studied, 85 compounds were identified by GC–MS. Carvone was the dominant constituent in the carvone chemotype (up to 58.1%), whereas menthol reached 30.7% in the menthol chemotype. Hierarchical clustering of CLR-transformed GC–MS data revealed three well-defined chemotypes among the analyzed Mentha EOs: carvone chemotype (three samples), menthol chemotype (five samples) and mixed, carvone-menthol chemotype (two samples). The antimicrobial activity of EOs was evaluated against 17 clinical antibiotic-sensitive and antibiotic-resistant microorganisms by the agar well diffusion method. The strongest antimicrobial activity was observed against resistant clinical Staphylococcus aureus strains, with MIC values as low as 0.10 mg/mL. EOs with a high carvone content consistently showed higher activity, especially against S. aureus, including resistant phenotypes. In contrast, menthol-chemotype EOs were associated with reduced antibacterial effectiveness. The obtained results demonstrate that the investigated commercial mint teas differ considerably in their phytochemical composition and biological properties, which may contribute to differences in their potential nutraceutical relevance as functional plant-derived beverages. Full article

Freshwater contamination by phosphate and pathogenic bacteria requires low-cost multifunctional treatment materials. Unlike previous studies that use a single biogenic agent to synthesize a single nanoparticle type, this work uses one fixed Aloe vera extraction protocol to generate three chemically distinct nanoparticles (Ag, CuO, Fe₃O₄) on the same waste-derived carbon support, enabling a direct, extract-controlled comparison of nanoparticle identity on water-treatment performance. Activated carbon (AC) was prepared from waste wattle bark (Acacia mearnsii) by steam activation at 700 °C and functionalized with biogenically synthesized Ag, CuO, and Fe₃O₄ nanoparticles (NPs) using Aloe vera extract as a reducing and stabilizing agent. Average nanoparticle sizes were 43 nm for Ag, 59 nm for CuO, and 13 nm for Fe₃O₄. FTIR, PXRD, SEM-EDS, TEM, DLS, TGA, and BET analysis characterized the materials. Among the composites, Fe₃O₄NPs/AC showed the best phosphate removal performance, achieving 93% removal and a maximum adsorption capacity of 9.3 mg/g under acidic conditions, compared with 3.3 mg/g for pristine AC. Equilibrium data were better described by the Freundlich model (R² = 0.999), indicating adsorption on a heterogeneous surface. Ag NPs/AC exhibited complete inactivation of both Escherichia coli and Staphylococcus aureus within 2 h, while CuO NPs/AC (a more economical alternative) achieved near-complete inactivation of both bacteria within 6 h. AC from spent wattle bark and functionalized with green-synthesized nanoparticles is thus a promising platform for combined phosphate removal and antibacterial water treatment. Consistent with their respective roles, Fe₃O₄ NPs/AC was evaluated exclusively for phosphate adsorption, while Ag NPs/AC and CuO NPs/AC were evaluated exclusively for antibacterial activity; no single composite was tested for both functions. Full article

Soybean residue, a major by-product of soy milk and tofu processing, is a large-yield and nutrient-rich substrate, but it is currently experiencing low utilization rates. In this study, a prodigiosin-producing strain, Serratia marcescens BD2025, was isolated from naturally fermented soybean residue. Subsequently, prodigiosin was produced by solid-state fermentation of soybean residue, and the fermentation conditions were further optimized by a Box–Behnken (BBD) model involving the soybean residue-to-water ratio, inoculum size, and temperature. Under the optimized conditions of a soybean residue-to-water ratio of 1:4.28, an inoculum size of 5.2%, and cultivation at 27.5 °C for 48 h, the prodigiosin yield reached 19.05 mg/g. High-performance liquid chromatography analysis showed that the major pigment peak had a retention time comparable to that of a prodigiosin standard, with an estimated purity of 96% based on peak area normalization. The results show that prodigiosin remains relatively stable at below 40 °C, in acidic conditions, and in darkness. The extracted prodigiosin inhibited both Escherichia coli and Staphylococcus aureus, with stronger activity against S. aureus. The scavenging ability of DPPH radical was dose-dependent, with the scavenging activity of 93.13% at 5 mg/mL. These findings indicate that soybean residue can serve as a solid-state fermentation substrate for prodigiosin production and provide a basis for the value-added utilization of soybean-processing residues. Full article

Background: Public fitness facilities are high-contact environments that facilitate microbial transfer via shared surfaces; however, temporal dynamics and device-specific contamination patterns remain insufficiently characterized. Methods: A repeated-measures observational study was conducted in a fitness facility over five consecutive weekdays (Monday to Friday). A total of 180 surface samples were collected from 12 gym devices, each sampled three times daily (morning, noon, and evening). Surface-associated cultivable bacteria were recovered using culture-based methods followed by MALDI-TOF MS identification. Ecological metrics, including species richness and Shannon diversity, were calculated, and taxa were classified by origin (skin-associated versus environmental). Device-specific contamination profiles were developed using a composite index incorporating pathogen presence, contamination frequency, and persistence. Temporal trends and predictors of contamination were analyzed using mixed-effects regression models. All statistical analyses were performed in R. Results: A total of 248 bacterial isolates were identified, representing 61 species across 32 families, with a predominance of skin-associated taxa (72.2%). Sampling time point was a strong independent predictor of contamination (adjusted OR for noon vs. morning: 7.19; p < 0.001). While overall microbial diversity remained stable across devices (Shannon index, p = 0.44), substantial heterogeneity was observed in pathogen prevalence, multispecies burden, and persistence. The functional trainer and leg extension showed the highest composite risk scores (42.3%), while the ab crunch machine and upper body ergometer demonstrated significantly increasing contamination trends over the sampling period (p < 0.05). Co-occurrence analysis showed nonrandom microbial associations, with the strongest positive links between Micrococcus luteus and Staphylococcus saprophyticus (Φ = 0.76) and Staphylococcus aureus (Φ = 0.61). Conclusions: Gym equipment surfaces harbor predominantly human-associated microbial communities exhibiting dynamic temporal contamination patterns, and on selected devices, increasing the baseline contamination across consecutive cleaning cycles. The findings indicate that contamination patterns on shared fitness equipment are dominated by taxa commonly associated with human skin and support targeted hygiene interventions focused on frequently contacted devices and periods of elevated contamination. Full article

Polysaccharide-based films are widely studied as topical systems due to their biocompatibility and tunable structural properties. In this study, composite films based on agar–chitosan (A-series) and gellan–chitosan (G-series) were developed with naringin as a bioactive component. The effects of polymer composition and naringin loading on structural organization, swelling behavior, antibacterial activity, and biocompatibility were evaluated. The results show that agar-based systems exhibited significantly higher swelling (~1370%), indicating a more open and highly hydrated structure, whereas gellan-based films formed more compact networks with moderate swelling (~347%). The incorporation of naringin (0.25 g per formulation) led to a pronounced increase in swelling in gellan-based systems (~777%), suggesting reduced network density, while only a slight effect was observed for agar-based films (~1444%). Antimicrobial studies against Staphylococcus aureus confirmed activity in both systems. The gellan-based formulation showed increased antibacterial activity with higher naringin loading (up to 30.0 ± 0.0 mm), whereas agar-based systems demonstrated maximum activity at lower naringin content (27.67 ± 0.58 mm). These findings indicate that antibacterial performance is influenced not only by the amount of bioactive compound but also by matrix structure and release characteristics. In vivo studies of selected A-series samples confirmed good tolerability of the naringin-loaded film (A1N1), with no signs of systemic toxicity or skin irritation, while anti-inflammatory activity under acute conditions was limited. Overall, the developed polysaccharide-based films show potential as topical systems; however, further optimization of polymer composition and formulation parameters is required to achieve a balance between structural stability and biological performance. Full article

Insects are continuously exposed to diverse microorganisms, including symbionts and pathogens, and rely on pattern-recognition receptors (PRRs) to initiate innate immune responses. Gram-negative bacteria-binding proteins (GNBPs) constitute an important class of the pivotal PRRs in insect immunity. However, whether GNBPs participate in immune responses against taxonomically distinct pathogens remains poorly understood. Red palm weevil (RPW), Rhynchophorus ferrugineus, is a notorious stem-boring insect pest that has caused huge economic loss worldwide. Our preliminary data indicated that the expression of RfGNBP5 could be induced dramatically upon the challenge of non-entomopathogenic bacteria Escherichia coli, Staphylococcus aureus and entomopathogenic fungus Beauveria bassiana. Here, it has been found that RfGNBP5 only possesses two conserved domains, a signal peptide and an intact glycoside hydrolase 16 (GH16) domain, but without the canonical carbohydrate-binding module (CBM39), implying that it might mediate insect immunity via its hydrolytic activity. RT-qPCR revealed that RfGNBP5 was expressed at the highest level in the hemolymph compared with other tissues and was significantly upregulated after exposure to pathogens, such as Escherichia coli, Staphylococcus aureus and Beauveria bassiana. Furthermore, the knockdown of RfGNBP5 potentiated the clearance efficiency of hemolymph against the invading pathogenic bacteria and fungi by increasing the expression level of two antimicrobial peptide genes, including RfAttacin in fat body and RfColeoptericin in gut, and augmenting the phenoloxidase (PO) activity in hemolymph. Taken together, these results suggested that RfGNBP5 acts as a negative regulator of RPW immunity, and it might be a potential candidate for further evaluation in RNAi-based pest management. Full article

Chronic infected wounds are often characterized by persistent bacterial colonization, biofilm formation, excessive oxidative stress, and prolonged inflammation, which severely impair tissue regeneration. To address these challenges, a multifunctional wound dressing capable of antibacterial activity and microenvironment modulation was developed. In this study, amide-modified hyaluronic acid (HA-ADH) was used as the matrix, and a dynamic coordination network was constructed via Cu²⁺-hydrazide interactions to form an in situ HA-Cu hydrogel. Curcumin-loaded DSPE-PEG2000 micelles were further incorporated to obtain a pH-responsive composite hydrogel (HA-Cu/Cur). The prepared hydrogel exhibited a porous interconnected structure, along with favorable injectability, self-healing capability, tissue adhesiveness, moderate swelling, controllable degradability, and pH-responsive behavior under acidic conditions. In vitro antibacterial assays demonstrated that both HA-Cu and HA-Cu/Cur effectively inhibited the growth and biofilm formation of Escherichia coli and Staphylococcus aureus. The antibacterial activity was associated with disruption of bacterial morphology, depletion of intracellular ATP, and induction of reactive oxygen species, while HA-Cu/Cur showed enhanced performance in antibiofilm activity and oxidative stress-related effects compared with HA-Cu. Cytocompatibility studies revealed that the hydrogel extracts exhibited negligible cytotoxicity toward L929 fibroblasts and RAW 264.7 macrophages, while promoting fibroblast migration and significantly reducing the expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in lipopolysaccharide-stimulated RAW 264.7 cells, with HA-Cu/Cur showing a more pronounced anti-inflammatory effect. In summary, the HA-Cu/Cur hydrogel integrates the antibacterial and pro-healing properties of Cu²⁺ with the antioxidant and anti-inflammatory activities of curcumin. The hydrogel effectively inhibited the growth and biofilm formation of both E. coli and S. aureus, reduced the expression of TNF-α, IL-6, and IL-1β in LPS-stimulated macrophages, and promoted fibroblast migration, demonstrating its potential as a multifunctional wound dressing for the management of infected wounds. Full article

Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), remains a leading cause of skin and soft tissue infections (SSTIs) worldwide. Patients with renal edema, including those with nephrotic syndrome and chronic kidney disease (CKD), and critical illness, are particularly susceptible because of barrier dysfunction, immune impairment, and altered antimicrobial pharmacokinetics. This narrative review examines the mechanisms linking renal edema to increased susceptibility to cutaneous S. aureus infection and discusses their diagnostic and therapeutic implications. Three interconnected pathophysiological pathways appear central to this susceptibility: disruption of the cutaneous barrier, nephrotic and uremic immune dysfunction, and impaired lymphatic immune surveillance. These abnormalities facilitate bacterial colonization, and invasion, while S. aureus further exploits the renal host through adhesins, toxins, biofilm formation, and immune-evasion mechanisms. The review also highlights the challenges of managing severe staphylococcal infections in patients with kidney disease and critical illness, where augmented renal clearance, expanded volume of distribution, extracorporeal renal support, and fluctuating renal function may substantially influence antimicrobial exposure. Current management requires early recognition, source control, individualized antimicrobial selection, renal-adapted dosing, therapeutic drug monitoring, and antimicrobial stewardship. Although emerging anti-virulence and immunomodulatory strategies show promise, most remain at the preclinical or early translational stage. Overall, renal edema should be regarded as a biologically active modifier of host–pathogen interactions that contributes to increased susceptibility to cutaneous S. aureus infection across the spectrum of kidney disease. Full article

Background: Atopic dermatitis is a chronic inflammatory skin disease in children, frequently associated with skin barrier dysfunction, immune dysregulation, and dysbiosis. Infected, treatment-resistant lesions may increase disease severity and complicate management, particularly in the presence of Staphylococcus aureus colonization. Objectives: To characterize the microbiological profile of infected, non-responsive pediatric atopic dermatitis, evaluate short-term clinical outcomes following individualized treatment, and identify predictors of disease severity. Methods: This observational analytical study included 41 children with atopic dermatitis recruited at Saint Constantin Hospital, Brașov, Romania, between September 2025 and February 2026. Eligible patients fulfilled the Hanifin and Rajka criteria and presented with infected, treatment-resistant lesions. Skin cultures were subjected to an antibiogram and antifungigram. Disease severity was assessed using the Patient-Oriented Eczema Measure (POEM) and SCORAD at baseline, 7 days, and 30 days. Repeated-measures ANOVA, mixed ANOVA, and hierarchical linear regression were used for statistical analysis. Results: Staphylococcus aureus was the predominant pathogen, followed by other bacterial species. Both POEM and SCORAD scores improved significantly over the 30-day follow-up, with marked improvement after 7 days and further reduction by day 30. Although patients with S. aureus colonization and those receiving systemic therapy tended to have higher disease severity, neither factor significantly influenced the trajectory of clinical improvement. Baseline disease severity was the strongest predictor of 30-day POEM and SCORAD outcomes, whereas demographic and perinatal characteristics did not independently predict short-term clinical outcomes. Conclusions: Individualized management was associated with significant improvements in clinician-assessed disease severity and patient-reported symptoms during the 30-day follow-up. Staphylococcus aureus, particularly methicillin-sensitive S. aureus (MSSA), was the most frequently isolated pathogen. Baseline disease severity was the strongest predictor of short-term clinical outcomes, whereas the evaluated demographic and perinatal characteristics did not provide additional predictive value in this cohort. Larger prospective controlled studies are needed to confirm these findings. Full article

Antimicrobial resistance demands intensive research on new nonantibiotics and drug repurposing to expand the arsenal of antimicrobial agents. The present work analysed the combination of diclofenac (DFNAC) and cannabidiol (CBD) and evaluated its potentiation and its biocompatibility. The formulation’s potency has been tested against Staphylococcus epidermidis (S. epidermidis), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and P. aeruginosa. The DFNAC-CBD combination showed an evident synergistic effect, a significant decrease in the minimum inhibitory concentration against Staphylococcus epidermidis, and an additive effect against Staphylococcus aureus, indicating the levels of cooperation between the two compounds. All tested treatments exhibited MBC/MIC ratios ≤ 4, indicating bactericidal activity according to accepted interpretative criteria. Overall, the DFNAC-CBD combination accelerated bacterial killing relative to the individual compounds and exhibited a clear time-dependent antibacterial effect. The combination exhibited no antibacterial activity against Gram-negative strains such as E. coli and Pseudomonas aeruginosa. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Lactate Dehydrogenase (LDH) assays demonstrated that the antibacterial concentration (3.906 µg/mL) preserves cell viability and membrane integrity. Live/dead staining confirms cell viability and normal morphology. The results indicate that the DFNAC-CBD combination achieves antimicrobial efficacy through bactericidal rather than merely bacteriostatic activities and without inducing significant cytotoxicity. Therefore, the proposed DFNAC-CBD combination has significant potential as a nonantibiotic formula, which with further profile analysis can develop into formulations that can control the use and dosage of common antibiotics. Full article