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Search Results (10,348)

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19 pages, 1272 KB  
Article
LC-MS/MS-Analysis and Biological Evaluation of Hop (Humulus lupulus): Antioxidant, Antidiabetic, Anticholinergic and Antiglaucoma Activities
by Kubra Aslan, Ulkuye Dudu Gul, Mustafa Arık, Mustafa Abdullah Yilmaz, Oğuz Cakir and İlhami Gulcin
Processes 2026, 14(7), 1073; https://doi.org/10.3390/pr14071073 (registering DOI) - 27 Mar 2026
Abstract
This study investigates the antioxidant, enzyme inhibitory, and antimicrobial activities of water (WEHL) and ethanol (EEHL) extracts of hop (Humulus lupulus) cones. Phytochemical analyses revealed higher total phenolic content in EEHL (271.52 ± 0.13 mg GAE/g) than in WEHL (251.84 ± [...] Read more.
This study investigates the antioxidant, enzyme inhibitory, and antimicrobial activities of water (WEHL) and ethanol (EEHL) extracts of hop (Humulus lupulus) cones. Phytochemical analyses revealed higher total phenolic content in EEHL (271.52 ± 0.13 mg GAE/g) than in WEHL (251.84 ± 0.06 mg GAE/g), as well as higher total flavonoid content (182.56 ± 0.45 mg QE/g for EEHL versus 179.39 ± 0.46 mg QE/g for WEHL). Antioxidant activity, determined by DPPH and ABTS assays, showed that EEHL had stronger radical scavenging capacity with IC50 values of 19.13 ± 4.66 μg/mL (DPPH) and 12.66 ± 1.94 μg/mL (ABTS), compared to WEHL (DPPH: 20.90 ± 2.39 μg/mL; ABTS: 32.41 ± 4.29 μg/mL). In reducing assays, EEHL also showed better absorbance values in FRAP (0.77 ± 0.01), CUPRAC (2.09 ± 0.05), and Fe3+ reducing (1.95 ± 0.01) tests. EEHL likely outperformed WEHL due to solvent polarity and extraction efficiency. Moderately polar ethanol extracts a broader range of phenolics and flavonoids, including fewer polar bioactive compounds that contribute to antioxidant capacity and enzyme inhibition. This matches higher TPC/TFC in EEHL and explains stronger radical scavenging, reducing power, and multi-enzyme inhibition. Enzyme inhibition studies revealed that EEHL inhibited acetylcholinesterase (IC50: 26.06 μg/mL), butyrylcholinesterase (IC50: 44.00 μg/mL), α-glycosidase (IC50: 119.31 μg/mL), and carbonic anhydrase isoenzymes hCA I (IC50: 59.78 μg/mL) and hCA II (IC50: 21.19 μg/mL). LC–MS/MS analysis identified major phenolic compounds such as isoquercitrin (3.14 ng/mL), rutin (0.60 ng/mL), and hesperidin (0.43 ng/mL) in EEHL. Antimicrobial screening showed selective activity against Staphylococcus aureus with an inhibition zone of 18.50 ± 0.58 mm, while no inhibition was observed against Escherichia coli and Candida albicans. These findings provide a solvent-dependent in vitro profile that can guide extraction strategies, support antioxidant and multi-enzyme screening (including hCA I and II), and identify candidates for selective antimicrobial evaluation and further preclinical investigation. Despite extensive use of hop extracts, comparative solvent-dependent profiling that links LC–MS/MS phenolic composition with a broad multi-enzyme inhibition panel, including the less frequently evaluated hCA I/II isoenzymes, remains limited. Therefore, the objective of this study was to systematically compare WEHL and EEHL in terms of phytochemical content and in vitro antioxidant, enzyme inhibitory, and antimicrobial activities. Overall, these results provide a solvent-dependent, comparative in vitro profile of WEHL vs. EEHL that can support antioxidant, multi-enzyme screening (including hCA I and II), and selective antimicrobial assays. Full article
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17 pages, 2362 KB  
Article
Inactivated Klebsiella pneumoniae Induces Metabolic and Hematopoietic Reprogramming to Promote Trained Immunity and Heterologous Antibacterial Protection
by Xiang Cheng, Shaoqiong Huang, Zhidong Hu and Xiaoyong Fan
Vaccines 2026, 14(4), 300; https://doi.org/10.3390/vaccines14040300 - 27 Mar 2026
Abstract
Background: Infections caused by multidrug-resistant bacteria and inadequate vaccine coverage against opportunistic pathogens highlight the need for interventions that broadly and durably enhance host defense beyond antigen-specific adaptive immunity. Trained immunity, driven by metabolic and epigenetic reprogramming of innate immune cells, has been [...] Read more.
Background: Infections caused by multidrug-resistant bacteria and inadequate vaccine coverage against opportunistic pathogens highlight the need for interventions that broadly and durably enhance host defense beyond antigen-specific adaptive immunity. Trained immunity, driven by metabolic and epigenetic reprogramming of innate immune cells, has been predominantly characterized using Bacille Calmette–Guérin and β-glucan, whereas its induction by Gram-negative bacteria remains poorly defined. To address this gap, we aimed to determine whether heat-killed Klebsiella pneumoniae (HK Kp) induces trained immunity through metabolic and hematopoietic reprogramming to confer heterologous antibacterial protection. Methods: HK Kp-trained murine bone marrow-derived macrophages and HK Kp-immunized C57BL/6 mice were employed to interrogate functional, metabolic, and transcriptomic reprogramming in vitro, hematopoietic progenitor remodeling in vivo, and protective efficacy against systemic Salmonella Typhimurium and Staphylococcus aureus infection. Results: HK Kp-trained macrophages showed markedly enhanced IL-1β secretion across all restimulation conditions, stimulus-dependent amplification of TNF-α responses, increased phagocytosis, and improved intracellular control of S. typhimurium, together with sustained upregulation of the glycolytic enzymes-encoding genes Hk2 and Pfkfb3. Transcriptomic profiling revealed extensive reprogramming enriched in glycolysis/gluconeogenesis and hematopoietic cell lineage pathways. In vivo, HK Kp immunization shifted bone marrow stem/progenitor compartments toward a myeloid-biased state. HK Kp-trained mice challenged with lethal S. typhimurium or S. aureus exhibited less weight loss, improved survival rates, and reduced bacterial burdens. Conclusions: Inactivated K. pneumoniae orchestrates metabolic and hematopoietic reprogramming to establish enhanced innate immune responsiveness and confer heterologous protection in murine S. typhimurium and S. aureus sepsis models, supporting its potential as a potent inducer of trained immunity. These findings establish HK Kp-based trained immunity as a promising strategy for combating multidrug-resistant and vaccine-evading pathogens. Full article
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12 pages, 1250 KB  
Case Report
PR3-ANCA-Associated Vasculitis in IgGκ MGUS: A Fatal Case of Rapidly Progressive Glomerulonephritis
by Carlos Berrocal, Álvaro Arbeláez-Cortés, Alyi Arellano, Antonio Peña, H. A. Nati-Castillo, Nancy Mejia, Alice Gaibor-Pazmiño, Marlon Arias-Intriago and Juan S. Izquierdo-Condoy
J. Clin. Med. 2026, 15(7), 2554; https://doi.org/10.3390/jcm15072554 - 27 Mar 2026
Abstract
Background: Rapidly progressive glomerulonephritis (RPGN) is a severe nephrological emergency, frequently secondary to anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. In older adults, the coexistence of comorbidities and monoclonal gammopathy of undetermined significance (MGUS) makes it difficult to distinguish between ANCA vasculitis and monoclonal [...] Read more.
Background: Rapidly progressive glomerulonephritis (RPGN) is a severe nephrological emergency, frequently secondary to anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. In older adults, the coexistence of comorbidities and monoclonal gammopathy of undetermined significance (MGUS) makes it difficult to distinguish between ANCA vasculitis and monoclonal gammopathy of renal significance (MGRS), which differ in prognosis and treatment. The coexistence of PR3-ANCA-associated vasculitis and MGUS is uncommon and sparsely documented. Case Presentation: A 72-year-old woman with hypertension and type 2 diabetes presented with acute deterioration and rapidly progressive renal failure, requiring hemodialysis. She had subnephrotic proteinuria, hematuria, and an active urinary sediment. The autoimmune workup showed ANCA negativity using immunofluorescence, but PR3-ANCA positivity using ELISA. Hematologic characterization documented an IgG kappa monoclonal spike; no bone lesions, amyloidosis, or criteria for multiple myeloma were found; and the patient was classified as MGUS. Renal biopsy revealed necrotizing extracapillary pauci-immune glomerulonephritis with cellular and fibrocellular crescents and no monoclonal deposits, consistent with PR3-ANCA vasculitis. Induction therapy with methylprednisolone pulses and oral prednisone was initiated; cyclophosphamide was not administered because of catheter-associated Staphylococcus aureus bacteremia and upper gastrointestinal bleeding complicated by disseminated intravascular coagulation. The patient died on day 25 due to infectious and hemorrhagic complications. Conclusions: This case provides additional documentation of an uncommon overlap between PR3-ANCA-associated vasculitis and MGUS in a Latin American patient and highlights the role of renal biopsy in distinguishing MGRS from pauci-immune vasculitis in the presence of paraproteinemia. It also underscores the need to tailor immunosuppression in frail older adults, balancing disease control against the risk of severe infection. Full article
(This article belongs to the Special Issue Personalized Therapy and Clinical Outcome for Vasculitis)
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19 pages, 1162 KB  
Article
Investigating the Sharing of Staphylococcus spp. Between Dogs and Their Owners: A Comparative Study from Two Italian Veterinary Teaching Hospitals
by Francesca Paola Nocera, Patrizia Robino, Rossana Schena, Stefano Cavalli, Alessandro Bellato, Ilaria Prandi, Davide Mancusi, Annunziata Romano, Sinem Arslan, Giulia Iamone, Matteo Olimpo, Gerardo Fatone, Luisa De Martino and Patrizia Nebbia
Pathogens 2026, 15(4), 356; https://doi.org/10.3390/pathogens15040356 (registering DOI) - 27 Mar 2026
Abstract
Animal health is a key pillar of the One Health framework, which emphasizes the interconnectedness of humans, animals, and the environment. Staphylococcus spp., common commensals of skin and mucosa, are clinically important due to their virulence factors and increasing antimicrobial resistance. This cross-sectional [...] Read more.
Animal health is a key pillar of the One Health framework, which emphasizes the interconnectedness of humans, animals, and the environment. Staphylococcus spp., common commensals of skin and mucosa, are clinically important due to their virulence factors and increasing antimicrobial resistance. This cross-sectional study aimed to isolate and characterize Staphylococcus spp. from dogs and their owners and to assess correlations within their nasal microbiota. Nasal swabs were collected from at least 100 dog–owner pairs at two Veterinary Teaching Hospitals located in Northern (Turin Province) and Southern (Naples Province) Italy. In both study areas, S. pseudintermedius was the most common species in dogs. Among owners, S. epidermidis was predominant in Naples, while S. epidermidis and S. aureus were most frequent in Turin. A subset of 54 dog–owner pairs sharing the same Staphylococcus species (42 from Turin and 12 from Naples; in total 108 isolates) was included in this analysis, with a focus on antimicrobial patterns. S. aureus was the species most frequently shared between dogs and owners, followed by S. epidermidis, with no significant differences between the two sites. In particular, methicillin resistance (phenotypically inferred) was detected in 16.7% of isolates in Turin (19.0% in dogs; 14.3% in owners) and 41.7% of isolates in Naples (33.3% in dogs; 50.0% in owners). Multidrug resistance was detected in 34.3% of paired isolates overall, with a higher prevalence in Naples (58.3%) compared to Turin (27.4%). No significant association emerged between biofilm production and multidrug resistance (MDR). Overall, these findings suggest possible species sharing between dogs and owners, while biofilm formation did not predict MDR. Full article
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18 pages, 6085 KB  
Article
Influence of Organic Salts on Molecular Interactions, Film Performance, and Antimicrobial Activity of TPS/PBAT Blown Films
by Vannet Roschhuk, Phanwipa Wongphan, Yeyen Laorenza, Phatthranit Klinmalai and Nathdanai Harnkarnsujarit
Foods 2026, 15(7), 1148; https://doi.org/10.3390/foods15071148 - 27 Mar 2026
Abstract
This study investigates the effects of organic salts, including sodium citrate (SC), calcium citrate (CC), and calcium lactate (CL), on the structure–property–function relationships of thermoplastic starch/poly(butylene adipate-co-terephthalate) (TPS/PBAT) films for active packaging applications. TPS incorporated with organic salts was prepared via twin-screw extrusion, [...] Read more.
This study investigates the effects of organic salts, including sodium citrate (SC), calcium citrate (CC), and calcium lactate (CL), on the structure–property–function relationships of thermoplastic starch/poly(butylene adipate-co-terephthalate) (TPS/PBAT) films for active packaging applications. TPS incorporated with organic salts was prepared via twin-screw extrusion, blended with PBAT, and further processed into blown films. The films were systematically characterized using 1H NMR, FTIR, and SEM, together with optical, mechanical, water vapor permeability, and antimicrobial evaluations against Staphylococcus aureus. The results revealed that SC primarily modulated hydrogen-bonding interactions within the starch matrix, resulting in improved structural homogeneity, balanced mechanical properties, and the highest antimicrobial activity among all formulations. In contrast, CL and CC promoted ionic crosslinking through Ca2+–starch interactions, leading to increased stiffness and Young’s modulus but reduced polymer chain mobility and limited release of active species, particularly in CC-containing systems. These differences in molecular interactions were consistent with variations in film microstructure, where SC-containing films exhibited more uniform morphologies, while calcium-based systems showed denser but less permeable structures. Furthermore, films containing SC and CL at appropriate concentrations achieved a favorable balance between transparency, water vapor barrier properties, and antimicrobial performance. Overall, this study provides new mechanistic insights into how monovalent and divalent organic salts govern intermolecular interactions, microstructure, and functional performance in TPS/PBAT systems. The findings highlight the critical role of additive type and concentration in designing biodegradable active packaging materials with tunable mechanical, barrier, and antimicrobial properties. Full article
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20 pages, 2260 KB  
Article
Cytotoxic Potential Evaluation of Innovative Pressurised Cyclic Solid–Liquid Extracts from Withania somnifera
by Rosanna Culurciello, Karen Power, Sergio Esposito, Ilaria Di Nardo, Simone Landi, Gionata De Vico, Domenico Palatucci, Elio Pizzo, Daniele Naviglio and Armando Zarrelli
Plants 2026, 15(7), 1027; https://doi.org/10.3390/plants15071027 - 26 Mar 2026
Abstract
Ethnopharmacological relevance. Withania somnifera (L.) Dunal, widely used in traditional medical systems such as Ayurveda, Unani, and Middle Eastern folk medicine, is valued for its adaptogenic, anti-inflammatory, neuroprotective, antimicrobial, and anticancer properties. These activities are primarily attributed to withanolides, with Withaferin A [...] Read more.
Ethnopharmacological relevance. Withania somnifera (L.) Dunal, widely used in traditional medical systems such as Ayurveda, Unani, and Middle Eastern folk medicine, is valued for its adaptogenic, anti-inflammatory, neuroprotective, antimicrobial, and anticancer properties. These activities are primarily attributed to withanolides, with Withaferin A recognized as one of the most bioactive constituents. Although traditional preparations often rely on the root, leaf use provides a more sustainable alternative and may yield significant quantities of active metabolites. Identifying efficient, modern extraction technologies that can enhance the recovery of bioactive compounds from leaves is essential for developing effective, standardized ethnopharmacological formulations. Materials and methods. Plants of W. somnifera grown from seeds were subjected to different environmental conditions (control, drought, cold, yeast extract treatment). Leaves were extracted using Pressurized Cyclic Solid–Liquid Extraction (PCSLE) with hydroalcoholic solvents and compared with conventional infusion of dried leaves. Extracts were fractionated with solvents of varying polarity and analyzed by TLC, HPLC, and NMR for quantification of Withaferin A. Expression levels of key withanolide-biosynthetic genes (CAS, SMT1, DWARF1, CYP71, CYP76) were assessed using qRT-PCR. Antimicrobial activity of pure Withaferin A, aqueous extract, and hydroalcoholic PCSLE extract was evaluated through MIC and MBC assays against Gram-positive and Gram-negative strains. Cytotoxic activity was measured via MTT assays in six human cancer cell lines after 3, 6, and 24 h of treatment. Results. PCSLE yielded substantially higher levels of Withaferin A than traditional infusion, especially in medium-polarity fractions (chloroform and ethyl acetate), with concentrations reaching 0.70% in fresh leaf mass (4.8% dry weight), compared to 0.11% obtained by infusion. Gene expression analysis revealed that 24-week-old plants exhibited the highest transcription of withanolide-biosynthetic genes, and drought stress significantly upregulated CAS, SMT1, DWARF1, CYP71, and CYP716, indicating enhanced metabolic flux toward withanolide production. Hydroalcoholic PCSLE extracts showed broad-spectrum antimicrobial activity, with MIC and MBC values comparable to pure Withaferin A and demonstrating bactericidal effects against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes. The aqueous extract showed activity only against Gram-positive strains. Cytotoxicity assays demonstrated an optimistic, dose-dependent reduction in cell viability across all tumour cell lines treated with the hydroalcoholic PCSLE extract, closely mirroring the activity of pure Withaferin A and consistently exceeding the effect of the aqueous extract. IC50 values confirmed the high bioactive content of PCSLE extracts and suggested mechanisms like those known for Withaferin A. Conclusions. PCSLE proved to be a highly efficient extraction technology for obtaining leaf extracts rich in Withaferin A, outperforming conventional extraction methods while exploiting sustainable plant tissue. Developmental stage and drought stress significantly modulated the expression of genes involved in withanolide biosynthesis, highlighting agronomic strategies capable of enhancing metabolite production. Hydroalcoholic PCSLE extracts exhibited antimicrobial and cytotoxic activities comparable to pure Withaferin A, supporting their relevance as promising therapeutic candidates. These findings advocate for the use of W. somnifera leaves as a sustainable source of bioactive compounds and demonstrate that advanced extraction technologies can contribute to the development of innovative ethnopharmacological preparations for antimicrobial and anticancer applications. Full article
17 pages, 859 KB  
Article
Use of Thermography on Dairy Goats Under Elevated Ambient Temperature and Udder Inflammation
by Joel Bueso-Ródenas, Gema Romero, Alfonso Navarro, Elena Pérez, Pilar Gascó and José Ramón Díaz
Dairy 2026, 7(2), 27; https://doi.org/10.3390/dairy7020027 - 26 Mar 2026
Abstract
Infrared thermography has been proposed as a non-invasive tool for mastitis detection in dairy ruminants; however, the extent of environmental confounding and diagnostic performance in small ruminants remain poorly characterized. This study evaluated udder thermography in dairy goats through correlation analysis under winter [...] Read more.
Infrared thermography has been proposed as a non-invasive tool for mastitis detection in dairy ruminants; however, the extent of environmental confounding and diagnostic performance in small ruminants remain poorly characterized. This study evaluated udder thermography in dairy goats through correlation analysis under winter and summer conditions, and an experimental intramammary inflammation challenge using Staphylococcus aureus lipoteichoic acid, with receiver operating characteristic analysis using somatic cell count >1500 × 103 cells/mL as the reference standard. Strong positive correlations between ambient temperature and udder surface temperatures intensified substantially from winter to summer, while surface temperatures showed weak or absent correlations with rectal temperature. Experimental inflammation induced a 12-fold increase in somatic cell count (305 vs. 3658 × 103 cells/mL, p < 0.001); however, thermographic responses remained minimal and spatially inconsistent, with area under the curve values approximating 0.5 and weak correlations between thermographic measurements and somatic cell count. Environmental temperature variation and physiological thermoregulatory adjustments substantially exceeded the minimal thermal signal generated by intramammary inflammation, limiting diagnostic utility. Infrared thermography showed poor diagnostic utility for detecting experimentally induced intramammary inflammation in dairy goats under the tested conditions. Full article
(This article belongs to the Section Dairy Small Ruminants)
23 pages, 3319 KB  
Article
Synthesis, Antibacterial Activity, and Mechanism of C-6 Aminated β-Carboline Derivatives Against MRSA
by Qiuran Wei, Weida Liang, Hongda Qiu, Xing Zhao, Yang Li, Han Ouyang, Bowen Han, Lingling Zhao, Xiao Wang and Hongze Liang
Antibiotics 2026, 15(4), 339; https://doi.org/10.3390/antibiotics15040339 - 26 Mar 2026
Abstract
Background: The escalating spread of drug-resistant bacteria is intensifying the antibiotic resistance crisis, necessitating the urgent development of novel antimicrobial agents to address the resulting high global mortality rates and significant socioeconomic burden. Objectives: This study aimed to aminate the C-6 position of [...] Read more.
Background: The escalating spread of drug-resistant bacteria is intensifying the antibiotic resistance crisis, necessitating the urgent development of novel antimicrobial agents to address the resulting high global mortality rates and significant socioeconomic burden. Objectives: This study aimed to aminate the C-6 position of β-carboline and investigate the antibacterial activity and mechanism of action of the derivatives. Results: For the first time, 16 derivatives with various nitrogen-containing moieties, including aliphatic- and phenyl-amino, imidazolium, pyridinium, and quinolinium, were synthesized via amination at the C-6 position of β-carboline. These compounds exhibited moderate to good activity against Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Bacillus subtilis, with minimum inhibitory concentration (MIC) values ranging from 1.56 to 100 μg/mL. The study reveals that elongating an alkyl chain, incorporating a cationic scaffold, and expanding a π-delocalized system can enhance antibacterial activity. The most potent derivative from each series was selected for further mechanistic investigation against MRSA. All studied compounds demonstrated low hemolytic activity and low cytotoxicity. Studies on the antibacterial mechanism indicated that the compounds exert their antibacterial effects by disrupting bacterial cell walls and membranes. Additionally, two of the compounds were found to potentially disrupt the secondary structure of DNA. All tested compounds exhibited antibiofilm activity. Conclusions: Our findings demonstrate that amination modification at the C-6 position of β-carboline can enhance antibacterial activity by disrupting the cell wall membranes and interacting with bacterial DNA. These results provide a basis for further optimization of antibacterial agents based on β-carboline. Full article
(This article belongs to the Section Novel Antimicrobial Agents)
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18 pages, 936 KB  
Article
In Vitro Antimicrobial Potential of Medicinal Plant Extracts and Their Combinations Against Mastitis-Causing Bacteria in Dairy Cows
by Yuriy Balji, Leila Sultanayeva, Raikhan Mustafina, Meruyert Alyonova, Aleko Kalandia, Indira Djafaridze and Galia Zamaratskaia
Molecules 2026, 31(7), 1089; https://doi.org/10.3390/molecules31071089 - 26 Mar 2026
Abstract
Mastitis in dairy cows, caused by pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans, leads to substantial economic losses and contributes to antimicrobial resistance, emphasizing the need for natural alternatives. This study assessed the phytochemical composition, antioxidant activity, [...] Read more.
Mastitis in dairy cows, caused by pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans, leads to substantial economic losses and contributes to antimicrobial resistance, emphasizing the need for natural alternatives. This study assessed the phytochemical composition, antioxidant activity, and in vitro antimicrobial effects of ethanol extracts from ten medicinal plants, including Populus balsamifera buds, Syzygium aromaticum, and Humulus lupulus, as well as two multi-component plant mixtures and commercial products against reference strains and field isolates of mastitis pathogens. Extracts exhibited total phenolic contents ranging from 2.5 to 43.0 mg GE/g, with Populus balsamifera and Syzygium aromaticum demonstrating the strongest DPPH radical scavenging activity (IC50 1.89–2.9 mg/g extract). Disc diffusion assays demonstrated broad-spectrum inhibition, particularly for Populus balsamifera (15.1–19.1 mm inhibition zones) and Humulus lupulus (9.0–18.4 mm) against key pathogens; phenolic and flavonoid contents positively correlated with antimicrobial activity (r = 0.63–0.99, p < 0.001). Multi-component mixtures provided consistent broad-spectrum effects (12.6–17.2 mm). These phenolic-rich plant extracts represent promising alternatives to reduce antibiotic use in dairy mastitis management. Full article
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16 pages, 1788 KB  
Article
Biofilm Formation Patterns of S. epidermidis (RP62A) and S. aureus (UAMS-1) Are Defined by Orthopaedic Implant Materials and Surface Wear
by Tatyana Sevastyanova, Cornelia Loy, Barbara Schneider-Wald, Klaus Notarbartolo, Gregor Reisig, Stefanie Gaiser, Ali Darwich, Mohamad Bdeir, Alexander Blümke, Sascha Gravius and Andreas Schilder
Antibiotics 2026, 15(4), 338; https://doi.org/10.3390/antibiotics15040338 - 26 Mar 2026
Abstract
Background/Objectives: Staphylococcus epidermidis (RP62A) and Staphylococcus aureus (UAMS-1) are clinically relevant pathogens frequently implicated in implant-associated infections due to their ability to form biofilms. RP62A is typically linked to persistent, chronic, low-grade infections, whereas UAMS-1 is associated with acute, invasive disease. Both [...] Read more.
Background/Objectives: Staphylococcus epidermidis (RP62A) and Staphylococcus aureus (UAMS-1) are clinically relevant pathogens frequently implicated in implant-associated infections due to their ability to form biofilms. RP62A is typically linked to persistent, chronic, low-grade infections, whereas UAMS-1 is associated with acute, invasive disease. Both strains serve as representative models for chronic and acute periprosthetic joint infections (PJIs). The objective of this study was to examine and compare in vitro biofilm formation by RP62A and UAMS-1 on orthopaedic materials/disc surfaces of defined composition. Methods: In vitro biofilm formation assays were performed using orthopaedic disc surfaces composed of cobalt–chromium alloy (CoCr), titanium alloy (Ti), and polyethylene (PE) after 72 h of incubation. Biofilm biomass was quantified using crystal violet staining, with absorbance measured at OD570. A polystyrene (PS) surface served as a control. Additionally, retrieved orthopaedic explant components were used as substrates for in vitro biofilm assays, in which RP62A was incubated for 72 h on the explanted surfaces. Supporting assays on glass slides were conducted to examine strain-specific biofilm-related architecture. Results: In vitro biofilm mass quantification assays showed strong biofilm formation by RP62A across all tested surfaces, with the highest absorbance on CoCr (OD570 = 5.80 ± 0.19). Notably, biofilm formation on CoCr was 76% higher compared to PS (p < 0.0001). No significant differences were observed among all three surface discs (p > 0.1). Biofilm formation was highest on PE for UAMS-1 (OD570 = 1.29 ± 0.09) and was significantly greater than on Ti (178%, p < 0.001) and CoCr (196%, p < 0.0001). In the in vitro assays performed on retrieved explant components, RP62A showed pronounced biofilm accumulation on polyethylene tibial inserts, particularly in regions of mechanical wear and friction. Supporting assays on glass slides were performed to examine strain-specific surface microstructural, revealing dense network-like structures for RP62A and thinner, discontinuous layers for UAMS-1. Conclusions: RP62A formed dense biofilms in vitro on multiple orthopaedic implant materials and retrieved explant components, consistent with its association with chronic periprosthetic joint infections. Increased biofilm accumulation was observed on mechanically worn polyethylene surfaces. In contrast, UAMS-1 showed lower biofilm formation on metallic disc surfaces, indicating strain- and material-dependent differences. These findings highlight the relevance of implant material selection and surface integrity for strategies targeting biofilm-associated implant infections. Full article
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14 pages, 3218 KB  
Article
Antibacterial Activity and Mechanism of Protocatechuic Acid Against Pathogens Isolated from Canine Endometritis
by Xiaoyu Sun, Jingwen Bi, Dongxue Shi, Haiyue Xu, Yuqi Liang, Weitao Dong, Xingxu Zhao and Yong Zhang
Animals 2026, 16(7), 1018; https://doi.org/10.3390/ani16071018 - 26 Mar 2026
Abstract
Canine endometritis is commonly associated with bacterial infections caused by Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Streptococcus canis (S. canis), leading to reproductive disorders in dogs. With increasing concern regarding antimicrobial resistance, alternative therapeutic [...] Read more.
Canine endometritis is commonly associated with bacterial infections caused by Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Streptococcus canis (S. canis), leading to reproductive disorders in dogs. With increasing concern regarding antimicrobial resistance, alternative therapeutic strategies are needed. This study evaluated the in vitro antibacterial activity and underlying mechanisms of protocatechuic acid (PCA) against clinical isolates of these pathogens obtained from dogs diagnosed with endometritis. The antibacterial efficacy of PCA was assessed by determining minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), and bacterial growth curves. PCA inhibited the growth of all three pathogens, with MIC values of 4 mg/mL for E. coli and S. aureus and 2 mg/mL for S. canis. The MBCs for E. coli and S. aureus were equal to their MICs, while the MBC for S. canis was twice the MIC, indicating bactericidal activity. Mechanistic analyses demonstrated that PCA disrupted bacterial membrane integrity, induced membrane depolarization, reduced intracellular ATP levels, and increased reactive oxygen species (ROS) accumulation. These effects were supported by SYTO9/PI fluorescence staining and scanning electron microscopy. In conclusion, PCA exhibits notable in vitro antibacterial activity against key pathogens associated with canine endometritis and represents a promising natural antimicrobial candidate. Full article
(This article belongs to the Collection Clinical Pathology in Animals)
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3 pages, 325 KB  
Correction
Correction: Hui et al. Omics Reveals the Antibacterial Mechanism of Dihydromyricetin and Vine Tea Extract Against Staphylococcus aureus via Cell Wall and Membrane Disruption. Molecules 2026, 31, 313
by Qiaoni Hui, Ting Li, Keke He, Wei Ma, Ying Guo, Yao Zhang and Liya Song
Molecules 2026, 31(7), 1081; https://doi.org/10.3390/molecules31071081 - 26 Mar 2026
Abstract
In the original publication [...] Full article
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13 pages, 658 KB  
Proceeding Paper
Nannochloropsis sp. Extract as a Potential Functional Ingredient for Food Applications
by Valter F. R. Martins, Ana I. Lopes, Manuela Machado, Manuela E. Pintado, Rui M. S. C. Morais and Alcina M. M. B. Morais
Biol. Life Sci. Forum 2026, 56(1), 25; https://doi.org/10.3390/blsf2026056025 - 25 Mar 2026
Abstract
This present study provides a comprehensive and novel assessment of Nannochloropsis sp. extracts as multifunctional ingredients for food applications, combining lipid profiling, nutritional quality indices, and antimicrobial activity. The extracts were obtained by ultrasound-assisted hydroethanolic extraction (90% EtOH solution; 20 kHz pulses of [...] Read more.
This present study provides a comprehensive and novel assessment of Nannochloropsis sp. extracts as multifunctional ingredients for food applications, combining lipid profiling, nutritional quality indices, and antimicrobial activity. The extracts were obtained by ultrasound-assisted hydroethanolic extraction (90% EtOH solution; 20 kHz pulses of 30 s during 10 min). Nannochloropsis sp. biomass exhibited a high lipid content (36.6%), and GC-FID analysis of its extract revealed high concentrations of palmitic acid, palmitoleic acid, and eicosapentaenoic acid (EPA). Nutritional quality indices—including the index of atherogenicity (AI), the index of thrombogenicity (TI), and the hypocholesterolemic/hypercholesterolemic ratio (HH)—were favorable, and the health-promoting index (HPI) was high. Although the extract exhibited low antioxidant activity in ABTS, DPPH, and ORAC assays, it demonstrated inhibitory activity against Gram-negative (Yersinia enterocolitica, Escherichia coli, Salmonella enterica Serovar Enteritidis) and Gram-positive (Staphylococcus aureus, and Listeria monocytogenes) foodborne pathogens, with a minimal inhibitory concentration of 6.3–12.5 mg/mL. These findings highlight the novelty of positioning Nannochloropsis sp. extracts as multifunctional ingredients that couple favorable lipid nutrition with antimicrobial functionality, rather than as single-purpose bioactives. The results support their potential for application in healthy food formulations and shelf-life extension strategies. Full article
(This article belongs to the Proceedings of The 6th International Electronic Conference on Foods)
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23 pages, 4126 KB  
Article
Genome and Secondary Metabolites Analysis of Fusarium oxysporum BPF55 Associated with Blaps rynchopetera and Its Anti-MRSA Biofilm Potential
by Xiaolu Zhu, Haorong Yin, Dasong Yang and Yinhe Yang
J. Fungi 2026, 12(4), 236; https://doi.org/10.3390/jof12040236 - 25 Mar 2026
Abstract
Antimicrobial resistance (AMR) represents a critical global health challenge, with methicillin-resistant Staphylococcus aureus (MRSA) posing a significant threat in both hospital-acquired and community-associated infections. Research has demonstrated that biofilm formation is a key factor contributing to drug resistance in MRSA. In this study, [...] Read more.
Antimicrobial resistance (AMR) represents a critical global health challenge, with methicillin-resistant Staphylococcus aureus (MRSA) posing a significant threat in both hospital-acquired and community-associated infections. Research has demonstrated that biofilm formation is a key factor contributing to drug resistance in MRSA. In this study, we investigated an fungus, Fusarium oxysporum BPF55, isolated from Blaps rynchopetera, which inhibits MRSA biofilm formation. The aim of this research was to identify the fungal strain and comprehensively characterize its genomic features, as well as to evaluate its anti-MRSA biofilm potential. Whole-genome sequencing revealed a genome size of 50,097,681 base pairs, a GC content of 47.36%, and 16,507 predicted coding genes. AntiSMASH analysis identified 56 secondary metabolite biosynthetic gene clusters, including those involved in the synthesis of various natural products such as terpenes, non-ribosomal peptides, and polyketides. Using UPLC-MS/MS, 15 compounds were annotated from the ethyl acetate extract. Molecular docking studies demonstrated that four compounds exhibit varying affinities for SarA and AgrA, two key proteins involved in MRSA biofilm formation. Overall, these findings suggest that the fungus F. oxysporum BPA55 produces a variety of secondary metabolites and contains bioactive compounds with potential anti-MRSA biofilm activity. Full article
(This article belongs to the Special Issue Bioactive Secondary Metabolites from Fungi)
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20 pages, 9578 KB  
Article
Virulence Phenotypes Differentiate Persistent vs. Resolving Isolates of Human Staphylococcus aureus Bacteremia
by Liana C. Chan, Hong K. Lee, Ling Wang, Huiyuan Wang, Scott G. Filler, Alexandra Ciranna, Wessam Abdelhady, Yan Q. Xiong, Liang Li, Rachelle A. Gonzales, Felicia Ruffin, Vance G. Fowler, Arnold S. Bayer, Richard A. Proctor and Michael R. Yeaman
Antibiotics 2026, 15(4), 332; https://doi.org/10.3390/antibiotics15040332 (registering DOI) - 25 Mar 2026
Abstract
Background: Staphylococcus aureus bacteremia (SAB) is a common and life-threatening bloodstream infection often caused by methicillin-resistant SA (MRSA) isolates. Up to 35% of SAB patients fail to clear infection with gold-standard anti-MRSA antibiotics, even if the isolate meets susceptibility breakpoints in conventional assays [...] Read more.
Background: Staphylococcus aureus bacteremia (SAB) is a common and life-threatening bloodstream infection often caused by methicillin-resistant SA (MRSA) isolates. Up to 35% of SAB patients fail to clear infection with gold-standard anti-MRSA antibiotics, even if the isolate meets susceptibility breakpoints in conventional assays in vitro. Such outcomes are termed persistent and may involve small colony variant (SCV) adaptation of SA in vivo. Methods: In this study, we assessed virulence phenotypes and mechanisms in persistent (PB) vs. resolving (RB) MRSA isolates from SAB. Results: Overall, PB isolates caused less hemolysis or biofilm formation than RB isolates, but proteolysis was equivalent. Attenuation of these virulence phenotypes increased longitudinally during the course of SAB. Although PB vs. RB isolates had similar human endothelial cell invasion rates, PB isolates more frequently formed SCVs intracellularly and inversely correlated with pH. Study PB and RB isolates exhibited distinct susceptibilities to prototypic human host defense peptides (HDPs), which were influenced by antibiotics and pH. Furthermore, mechanistic signatures of HDPs differed between PB and RB isolates. Conclusions: Together, these results reveal that MRSA isolates from PB vs. RB outcomes of SAB have differential virulence profiles that suggest coordinated immune subversion in PB. Understanding MRSA adaptations that promote persistence in SAB may enable innovative agents and strategies to address these challenging infections. Full article
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