Search Results (10,354)

The global rise in antimicrobial resistance has spurred increased interest in alternative antimicrobial agents, particularly essential oils (EOs). These oils are complex mixtures of volatile compounds that exhibit documented biological activity. This study evaluated antimicrobial and antibiofilm effects of selected EOs against clinically relevant bacterial and fungal pathogens. Antimicrobial activity against planktonic cells was assessed using disc diffusion assays with DMSO-diluted EO solutions against Escherichia coli (E.coli), Staphylococcus aureus (S.aureus), Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans. Antibiofilm activity of E. coli and S. aureus was examined using ethanol-based EO formulations, with biofilm viability quantified by colony forming unit (CFU) enumeration. Cinnamon (Cinnamomum verum) oil showed the strongest and most consistent activity, inhibiting planktonic and biofilm models. Tea tree (Melaleuca alternifolia), lemongrass (Cymbopogon citratus), rosemary (Rosmarinus officinalis), rose (Rosa damascena), and jasmine (Jasminum officinale) oils showed significant planktonic antimicrobial effects, while jasmine oil (Jasminum officinale) demonstrated pronounced antibiofilm activity against S. aureus, including strong biofilm eradication in several replicates. In contrast, chamomile (Matricaria chamomilla) and sandalwood (Santalum austocaledonicum) oils showed limited or no activity. These findings highlight differences between planktonic and biofilm responses, emphasizing the importance of incorporating biofilm models into antimicrobial evaluation. Overall, Cinnamomum verum and Jasminum officinale oils may serve as complementary antimicrobial agents, warranting further investigation. Full article

The bioactive compounds in thyme essential oil (TEO) have been investigated as natural preservatives. However, their direct application in foods is limited by their poor water solubility and high volatility. In this context, nanoemulsions represent promising delivery systems for bioactive compounds due to their improved physicochemical stability and functional performance. This study aimed to develop and characterize TEO nanoemulsions prepared by ultrasound-assisted encapsulation using an ultrasonic probe and whey protein concentrate as a surfactant, with potential application in chicken burgers. Different sonication times (1, 3, 5, 7, and 10 min) were evaluated, and ultrasonication time was evaluated as the experimental variable. The formulation processed for 3 min presented the smallest hydrodynamic diameter (289 nm) and a homogeneous spherical morphology. The nanoemulsions showed low cytotoxicity, maintaining cell viability above 90% at all evaluated concentrations. In vitro antibacterial assays demonstrated activity against Staphylococcus aureus and antifungal effects against Aspergillus and Penicillium species. When applied to chicken burgers, the treatment containing 100 ppm of nanoencapsulated TEO contributed to reductions in S. aureus and mesophilic aerobic microorganism counts during 7 days of refrigerated storage. These findings indicate that TEO nanoemulsions present potential as natural antimicrobial systems for food preservation applications. Full article

Bacillus subtilis is aerobic or facultatively anaerobic. After entering the gastrointestinal tract, its spores germinate and colonize the gut, inhibiting the growth of harmful aerobic bacteria (Escherichia coli, Streptococcus, Staphylococcus aureus). However, it remains unclear whether B. subtilis can inhibit Clostridium perfringens type A infection. In this study, B. subtilis PB6 was added to the diets of pregnant sows infected with Clostridium perfringens type A, which significantly improved the reproductive performance and reduced the incidence of bloat in sows and diarrhea in neonatal piglets. The treatment significantly increased the abundance of intestinal probiotics (B. subtilis, Lactobacillus, Limosilactobacillus reuteri, Lactobacillus johnsonii, Muribaculaceae, Lactobacillus amylovorus, and Lactobacillus reuteri) in sows and decreased the relative abundance of Clostridium perfringens type A after feeding B. subtilis administration. These probiotics can repair the intestinal tissue and improve intestinal histomorphology, and enhance the expression of MUC2 and sIgA in sows, thereby further strengthening the mucosal immune function. B. subtilis can also reduce the levels of inflammatory factors (CRP, IL-1β, and IFN-γ) and attenuate the inflammatory response in sows and neonatal piglets. Taken together, our results suggest that dietary supplementation with B. subtilis PB6 could reduce bloat in sows and diarrhea in piglets while improving intestinal barrier function and microbial balance in sows. Full article

Introduction: Bacterial multidrug resistance (MDR) drives treatment with expensive, toxic, or pharmacokinetically suboptimal antibiotics. Objectives: To assess the prevalence of MDR Gram-positive cocci among isolates from cardiac implantable electronic device (CIED) infections at a Polish reference center. Methods: Data come from the “EXTRACT” registry (ClinicalTrials.gov ID NCT05775783), which covers 702 transvenous lead extraction procedures. Blood samples and intraoperative swabs were collected from participants with CIED infection. Results: From 209 cases with isolated pocket infection (PI) (107, 51.2%) or systemic infections (102, 48.8%), 263 Gram-positive cocci were cultured. They were: coagulase-negative staphylococci (CoNS) (177, 67.3%), Staphylococcus aureus (62, 23.6%), enterococci (15, 5.7%), streptococci (8, 3.0%), and others (1, 0.4%). The highest MDR rate was among CoNS (46.9%). CoNS exhibited methicillin resistance (MR-CoNS) in 55.9% with co-resistance to macrolides (73.2%), lincosamides (51.0%), fluoroquinolones (56.1%), aminoglycosides (41.4%), tetracyclines (29.6%), and co-trimoxazole (29.3%). Resistance to daptomycin (5.3%) and linezolid (2.0%) in MR-CoNS was rare. The frequency of MDR S. aureus was 8.1%. Methicillin resistance in S. aureus (MRSA, 6.5%) co-occurred with resistance to macrolides/lincosamides and fluoroquinolones (100% for both) or linezolid (25.0%). All MDR staphylococci were vancomycin-susceptible. High-level aminoglycoside resistance (HLAR) in Enterococcus faecalis (53.8%) was accompanied by levofloxacin co-resistance (66.7%). Conversely, E. faecium HLAR (50.0%) strains showed 100.0% β-lactam resistance. Vancomycin-resistant enterococci (VRE) accounted for 6.7%; the VRE E. faecium strain was tigecycline- and linezolid-susceptible. Among viridans group streptococci, β-lactam and lincosamides resistance was common (40.0% for both), with 50.0% of co-resistance. Conclusions: Epidemiological data may improve the effectiveness of empirical antibiotic therapy for CIED-related infections. Full article

Quercetin, one of the most abundant flavonoids in nature, has attracted the attention of many researchers due to its chemical and biological properties. A series of metal–quercetin complexes (Cu²⁺, Co²⁺, Zn²⁺, Sn²⁺, Al³⁺, Cd²⁺ and Mg²⁺) were synthesized and systematically characterized by Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV–Vis) and nuclear magnetic resonance (NMR). These analyses confirmed that the complexes predominantly form through coordination with the 4-carbonyl group and adjacent phenolic hydroxyls. This induces measurable shifts in the ν(C=O), ν(O–H), and π→π* transition bands relative to free quercetin. The antioxidant capacity of the complexes was evaluated using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH^•) radical scavenging method, 2,2′-Azinobis(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS^•)⁺ radical activity, and Ferric Reducing Antioxidant Power (FRAP) assay. Several complexes exhibited higher radical scavenging efficiency than quercetin, with inhibition percentages exceeding 80% in the DPPH^• and ABTS^•+ assays. Others showed reduced activity due to the masking of redox-active hydroxyl groups during metal coordination. FRAP results corroborated these trends, indicating metal-dependent modulation of reducing power. Antimicrobial evaluation revealed that selected complexes were more active than free quercetin, particularly against Staphylococcus aureus and Candida spp., with minimum inhibitory concentrations (MICs) ranging from 75–250 μg mL⁻¹. Overall, metal complexation significantly alters the electronic structure and biological behavior of quercetin, highlighting the potential of metal–flavonoid complexes as multifunctional antioxidants and antimicrobials. Full article

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

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

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

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

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

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

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

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

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

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