Search Results (4,842)

Biodegradable magnesium (Mg) alloys are promising materials for temporary orthopaedic implants, combining favourable mechanical properties and superplastic behaviour with in vivo resorption. This enables (i) prolonged implant duration, (ii) fabrication of complex-shaped prostheses via superplastic forming (SPF), (iii) elimination of removal surgery, and (iv) reduced risk of long-term complications. However, rapid corrosion under physiological conditions remains a major limitation, highlighting the need for surface treatments that slow degradation while preserving implant integrity. This study investigates the effects of hydrothermal surface treatment on MgAZ31-SPF alloys, focusing on immunomodulatory responses, antibacterial potential, and degradation behaviour. Hydrothermally treated MgAZ31-SPF (MgAZ31-SPF-HT) extracts released lower Mg²⁺ concentrations (29.2 mg/dL) compared to untreated MgAZ31-SPF (47.5 mg/dL) while maintaining slightly alkaline pH (7–8.7), indicating improved control of early degradation. In vitro assays with human peripheral blood mononuclear cells (hPBMCs) and normal human dermal cells (NHDCs) showed that MgAZ31-SPF-HT extracts maintained higher cell viability over 24–72 h. Gene expression analysis revealed significant downregulation of pro-inflammatory markers CTSE and TNF-α, while protein quantification via ELISA and BioPlex confirmed reduced secretion of TNF-α, TGF-β1, TGF-β2, IL-6, and IL-8, suggesting mitigation of early immune activation. Antibacterial assays demonstrated limited Staphylococcus aureus colonisation on both MgAZ31-SPF and MgAZ31-SPF-HT scaffolds, with CFU counts (~10⁵–10⁶) well below the threshold for mature biofilm formation (~10⁸), and SEM analysis confirmed sparse bacterial distribution without dense EPS-rich layers. Overall, hydrothermal treatment improves Mg alloy biocompatibility by controlling Mg²⁺ release, modulating early immune responses, and limiting bacterial adhesion, highlighting its potential to enhance clinical performance of Mg-based implants. Full article

Background: Copper nanoparticles (CuNPs) are promising antibacterial agents, but instability and heterogeneity in ‘green’ routes limit translation. Methods: We developed a one-step synthesis in which pre-polymerized polycatechin acts as both reductant and capping agent to form copper–polycatechin core–shell nanoparticles (Cu@polycat). Physicochemical properties (TEM/DLS/XRD/FTIR/ζ), colloidal stability (pH, salt, serum), ion release, and antibacterial activity against planktonic and biofilm E. coli/S. aureus were evaluated. Results: Cu@polycat featured a ~21.5 nm metallic core and ~45 nm hydrodynamic diameter (shell ≈ 12 nm, estimated from TEM–DLS) with ζ ≈ −34 mV, conferring high stability across physiological conditions. Cu@polycat outperformed uncoated CuNPs, displaying 8-fold lower MICs and rapid bactericidal kinetics (>5-log10 in 6–8 h). Synergy between the copper core and polycatechin corona was confirmed (FICI ≈ 0.08). Cu@polycat inhibited biofilm formation by >80% and reduced viable counts in 24 h mature biofilms by ≥3-log10, whereas ampicillin was ineffective under the same biofilm conditions. Conclusions: A polycatechin-based green route furnishes a stable, synergistic nano-antibacterial platform with potent anti-biofilm activity, supporting development for wound-care and anti-fouling device coatings. Full article

Bacterial biofilms on different types of microplastics in aquatic environments have become an increasing ecological and public health concern. In this context, this study investigated biofilm formation on virgin and aged microplastics under marine conditions. Serratia marcescens biofilm formation was observed on both virgin and aged polyethylene particles after 7 days, with no significant changes by day 14. Concerning polypropylene microplastics, biofilms developed on aged particles but were not detectable on virgin particles, likely due to interference from the polypropylene red color matching S. marcescens cells. In contrast, expanded polystyrene spheres showed an initial biofilm formation that dissipated by day 14, potentially due to toxic residues from photooxidation, including potential styrene monomers and other chemical additives, inhibiting biofilm persistence. These findings indicate differences in biofilm formation across microplastics types, which may influence microplastic buoyancy and ecological impacts. Thus, microplastic color and additives should be considered in future studies on microplastics biofilm formation and biofouling. Full article

Chelerythrine (CHE) is a naturally occurring benzophenanthridine alkaloid obtained from plants such as Chelidonium majus L. It has received notable attention in pharmacology and microbial control because of its broad-spectrum activity and marked anti-inflammatory, apoptosis-inducing, and antibacterial effects. In this study, Bacillus tropicus, which frequently presents in the soil environment, was selected as the target microorganism to systematically examine the dose-dependent inhibitory influence of CHE on its growth curve, biofilm development, and survival rate. Furthermore, by simulating an antibiotic pressure environment in vitro, the original strain was subjected to continuous subculturing (30 times), and a highly drug-resistant B. tropicus strain capable of stable growth under high concentrations of CHE (300 mg/L) was successfully acclimated. After that, transcriptomics analysis was employed to compare the genetic differences between the wild-type bacterium and drug-resistant bacterium to determine how bacterial cells are able to resist CHE. A total of 868 genes in the CHE-resistant bacterium were revealed to be more active, while 539 genes were less active. These results indicate that the CHE resistance characteristics of the strain may be related to the adjustment of its sugar metabolism pathway and the biofilm formation pathway. As a widely used biological control bacterial strain, the successful acclimation of the B. tropicus strain with resistance to CHE has made it possible to use the combined formulation of these two agents for the prevention and control of plant diseases. Full article

Biofilms are structured microbial communities that adhere to biotic and abiotic surfaces embedded in an autonomous extracellular matrix. These structures contribute to persistent infections, especially in patients with indwelling medical devices, due to their resistance to antimicrobial agents; they have evolved to evade host immune responses. Despite advances in antimicrobial therapies, biofilm-associated infections remain a major challenge in clinical infectious diseases. This perspective explores the underlying mechanisms of biofilm resilience and immune evasion, emphasizing the limitations of conventional treatments and the need to develop pre-emptive measures that focus on preventing biofilm formation rather than implementing a treatment. This work discusses emerging strategies, such as quorum-sensing inhibition, hormonal modulation, matrix-degrading enzymes, anti-adhesive surface modifications, and nanotechnology-based drug delivery, that offer promising avenues to disrupt biofilm formation and maturation. Also offers a shift from the paradigm, looking into proactive prevention rather than treatment, emphasizing clinical translation, scalability, and biocompatibility. Embedding these strategies into routine care could significantly reduce healthcare-associated infections, improve patient outcomes, and mitigate the development of antimicrobial resistance. Our analysis highlights biofilm prevention as a critical frontier in the future of infectious disease management. Full article

Objectives: Pseudomonas aeruginosa is an opportunistic pathogen of high clinical relevance due to its ability to form biofilms, its inherent virulence regulated by quorum-sensing systems, and its multidrug resistance. In the present study, we evaluated the inhibitory potential of nine extracts from Inula species (chloroform and methanolic fractions, including a sesquiterpene lactone-enriched fraction) against biofilm formation and virulence-associated traits of P. aeruginosa PAO1 and three multidrug-resistant clinical isolates, as well as their cytotoxicity, biocompatibility, and ability to affect cytokine and nitric oxide production in infected skin explants. Methods: The following methods were applied: fractionation and extraction of plant extracts; cytotoxicity assessment on HFF cells; crystal violet assay for determining antibiofilm activity; fluorescence microscopy for evaluating biofilm viability; electron microscopy for assessing the 3D structure of biofilms and morphological alterations; inhibition assays of pyocyanin pigment, protease activity, bacterial motility, interleukin-17, and nitric oxide production; histological analysis of mouse skin explants. Results: Quantitative analyses of antibiofilm activity revealed that five of the tested extracts inhibited biofilm formation by more than 50%. Structural and functional analyses using confocal laser scanning microscopy and scanning electron microscopy demonstrated a substantial reduction in biofilm thickness, exfoliation of biofilm biomass, the presence of isolated bacterial clusters, metabolically inactive cell populations, and morphological abnormalities associated with cell elongation, invaginations, and polar deformations as a consequence of treatment. In addition, the plant extracts strongly affected virulence factors regulated by quorum sensing. The methanolic fractions from I. britannica and I. bifrons significantly suppressed pyocyanin synthesis. In contrast, the chloroform fractions from I. helenium and I. spiraeifolia produced the largest inhibition zones in assays for extracellular protease activity. Furthermore, all chloroform extracts suppressed bacterial motility, with the lowest swarming diameter observed for the chloroform and lactone-enriched fractions from I. britannica. The chloroform extracts of I. helenium and I. bifrons, methanolic extracts of I. britannica, and chloroform and methanolic extracts of I. spiraeifolia showed relatively low toxicity to normal diploid human fibroblasts. Methanolic and chloroform fractions from I. britannica disrupted biofilm integrity and reduced IL-17A and nitric oxide production in infected skin explants. Conclusions: All these findings indicate a possible synergistic action of the chemical constituents within the fractions on quorum-sensing regulation, biofilm formation, cellular viability, and modulation of host inflammatory responses. Full article

Cinnamon essential oil (CEO), a safe, medicinal, and edible Traditional Chinese Medicine (TCM) component, was investigated for its anti-Candida albicans property and ability to relieve intestinal inflammation. The anti-Candida albicans ability of CEO was evaluated by Minimum Inhibitory Concentration (MIC), 2,3-Bis-(2-Methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT), and Scanning Electron Microscope (SEM) methods. By constructing ulcerative colitis (UC) mice intestinally colonized by C. albicans, the CEO effects on the regulation of flora, the relief of intestinal inflammation, and possible related signal pathway were discussed. The results showed that CEO has a significant effect on inhibiting C. albicans, where the MIC₈₀ value was 265 μg/mL, and the Sessile Minimum Inhibitory Concentration (SMIC)₈₀ value was 530 μg/mL. SEM showed the CEO could inhibit C. albicans mycelium growth and biofilm formation. CEO can regulate the flora disturbance, reduce inflammatory factors level, and play a protective role in intestinal mucosal damage. Network pharmacology predicts CEO may be associated with Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) pathway. It was proved that CEO had an inhibitory effect on the JAK-STAT pathway by qPCR determination. These findings suggest CEO may have therapeutic potential for C. albicans–associated UC. Full article

Background: Small-scale food animal production is common worldwide but often underestimated as a source of antimicrobial resistance. This study aimed to determine the prevalence of MRSA and VRE-E. faecium, and ESBL-E. coli bacteria among workers and within the production environment of low-capacity slaughterhouses, as well as to analyze the antimicrobial resistance patterns of these bacteria and their ability to form biofilms. Methods: The measurements were carried out in three low-capacity slaughterhouses in Poland. Bioaerosol samples, swabs from the production environment fomite and carcasses, meat samples, and swabs from workers’ hands and nostrils were taken. The strains’ susceptibility to antibiotics was assessed using the disk diffusion method, and their biofilm-forming potential was assessed using the microplate method. Isolates were also tested for the presence of genes related to biofilm formation and resistance to antiseptics. Results: In this study, 13.8%, 20.5%, and 14.9% of the samples (n = 268) were positive for MRSA, ESBL-E. coli, and VRE-E. faecium, respectively, with the highest detection rates on pork carcasses and surfaces. MRSA and ESBL-E. coli bacteria were also detected in swabs from workers’ hands and nasal swabs, and in bioaerosol samples. Most isolates revealed multidrug resistance, including 89% of MRSA, 76% of ESBL-E. coli, and 83% of VRE-E. faecium. The majority of them were also capable of biofilm formation—81%, 65%, and 75%, respectively—emphasizing their survival capabilities in slaughterhouse environments. Conclusions: The slaughterhouse workers are regularly exposed to antibiotic-resistant bacteria such as MRSA, ESBL-E. coli, and VRE-E. faecium. To reduce these risks, it is essential for small slaughterhouses to strictly follow hygiene protocols, enhance the separation between clean and contaminated areas, improve ventilation, and ensure the use of protective measures. Full article

The escalating crisis of antibiotic resistance, particularly concerning foodborne pathogens such as Staphylococcus aureus and its biofilm contamination, has emerged as a major global challenge to food safety and public health. Biofilm formation significantly enhances the pathogen’s resistance to environmental stresses and disinfectants, underscoring the urgent need for novel antimicrobial agents. In this study, we isolated Bacillus strain B673 from the saline–alkali environment of Xinjiang, conducted whole-genome sequencing, and applied antiSMASH analysis to identify ribosomally synthesized and post-translationally modified peptide (RiPP) gene clusters. By integrating an LSTM-Attention-BERT deep learning framework, we screened and predicted nine novel antimicrobial peptide sequences. Using a SUMO-tag fusion tandem strategy, we achieved efficient soluble expression in an E. coli system, and the purified products exhibited remarkable inhibitory activity against Staphylococcus aureus (MIC = 3.13 μg/mL), with inhibition zones larger than those of the positive control. Molecular docking and dynamic simulations demonstrated that the peptides can stably bind to MurE, a key enzyme in cell wall synthesis, with negative binding free energy, suggesting an antibacterial mechanism via MurE inhibition. This study provides promising candidate molecules for the development of anti-drug-resistant agents and establishes an integrated research framework for antimicrobial peptides, spanning gene mining, intelligent screening, efficient expression, and mechanistic elucidation. Full article

Hyaluronic acid (HA) is a ubiquitous glycosaminoglycan essential for maintaining tissue hydration, structural integrity, and immunological homeostasis in vertebrates. Although traditionally regarded as a host-derived molecule, HA is also produced by a range of microorganisms, most notably Streptococcus spp., through specialized hyaluronan synthases (HAS). Microbial HA and host-derived HA fragments play key roles not only in tissue physiology but also in infection biology, influencing microbial virulence, biofilm formation, and immune evasion. In bacteria, HA-rich capsules promote adhesion, shield pathogens from complement-mediated opsonization and phagocytosis, and facilitate dissemination through host tissues. Conversely, HA-degrading enzymes and reactive oxygen species generate low-molecular-weight HA fragments that amplify inflammation by activating—toll-like receptor 2 (TLR2)/toll-like receptor 4 (TLR4) signaling, contributing to chronic inflammatory states. Furthermore, microbial HA modulates biofilm organization in both bacterial and fungal pathogens, enhancing persistence and antimicrobial tolerance. Clinically, widespread use of HA-based dermal fillers has generated increasing concern over delayed biofilm-associated infections, diagnostic challenges, and complications arising from microbial contamination and host–microbe interactions. Recent advances in HA engineering, including anti-microbial HA conjugates and receptor-targeted biomaterials, offer promising strategies to mitigate infection risk while expanding therapeutic applications. This review synthesizes current knowledge on HA biosynthesis across biological kingdoms, its dualistic role in health and disease, and its emerging relevance at the interface of microbiology, immunology, and biomedical applications. Full article

Candida and other pathogenic yeast species, able to transition from non-invasive commensal organisms to invasive pathogens, are characterized by a high ability to adapt to stress conditions encountered in the human host, such as pH and temperature shifts, CO₂ and oxygen level variations, and nutritional limitations. Although Candida albicans remains the main cause of Candida-related infections, non-albicans Candida (NAC) species, including C. tropicalis, C. parapsilosis, C. krusei, and non-Candida species such as Yarrowia lipolytica, Candidozyma auris, and Nakaseomyces glabratus, are gaining clinical importance. These species exhibit diverse mechanisms of pathogenicity, including morphological transition, modulation of gene expression pathways (cAMP-PKA/MAPK, Hsp, calcineurin, GlcNAc-mediated signaling), cell wall remodeling, post-translational reprogramming, biofilm formation, antifungal resistance, and enzyme secretion. C. albicans exhibits high morphological and metabolic plasticity for survival across body niches. N. glabratus and C. tropicalis show strong azole resistance and biofilm formation, while C. parapsilosis and C. krusei pose risks through surface adhesion and treatment resistance. C. auris stands out for heat tolerance, multidrug resistance, and outbreak potential. Y. lipolytica, though rare, forms persistent filamentous biofilms in critical care settings. Cryptococcus neoformans remains a life-threatening pathogen capable of immune evasion and crossing the blood–brain barrier. This review compares molecular mechanisms of pathogenicity across these fungi, emphasizing environmental adaptation, conserved and species-specific responses, and potentially highlighting targets for therapeutic management. Full article

Oral microbial biofilms play a critical role in the development of various oral infectious diseases, including periodontitis and tooth caries, with Streptococcus mutans recognized as a key biofilm-forming bacterium due to its strong adhesion and acidogenic capacity. Zinc oxide nanoparticles (ZnO NPs) have demonstrated antibacterial properties against various bacteria. This study investigated the antibacterial and antibiofilm properties of ZnO NPs on S. mutans and elucidated their mode of action. Bacterial cultures were exposed to increasing concentrations of ZnO NPs, and planktonic growth, biofilm biomass and biofilm metabolic activity were measured. Complementary assays assessed bacterial ATP content, pH shift in the media, reactive oxygen species (ROS) production, membrane integrity (SYTO 9/PI live/dead staining) and membrane potential. Morphological changes were examined by high-resolution scanning electron microscopy (HR-SEM), while gene expression was analyzed by real-time qPCR. We observed that ZnO NPs inhibited S. mutans growth and biofilm formation in a dose-dependent manner, with both the minimum inhibitory and biofilm inhibitory concentration of 0.5 mg/mL. ZnO NP treatment disrupted bacterial membranes, caused cytoplasmic leakage, and induced ROS production. EPS production determined by Congo Red staining was significantly reduced. Gene expression analysis revealed significant upregulation of vicR, luxS, wapA, gtpB, nox and ftsZ, and downregulation of spaP, gtpC and atpB. In conclusion, ZnO NPs compromise S. mutans viability and biofilm development through oxidative stress and membrane disruption, highlighting their potential use as bioactive materials in oral healthcare. Full article

Moraxella osloensis is an infrequently reported component of the human skin microbiota, but it has recently been recognized as a potential source of intraoperative contamination. Its pathogenic role remains poorly defined, particularly in shoulder arthroplasty. This study describes the recovery and characterization of M. osloensis from intraoperative periprosthetic tissue samples collected immediately after reverse total shoulder arthroplasty in five patients. All isolates exhibited low colony counts (10–50 CFU/mL), were uniformly susceptible to the antimicrobial agents tested, and did not produce β-lactamases. Biofilm formation—an important virulence determinant in periprosthetic joint infections—was detected in two of the five isolates. Clinically, no patient developed postoperative infection within 12 months, and only one experienced a transient superficial wound-healing delay, which resolved with a short administration of oral antibiotics. These findings indicate that M. osloensis may be present in the operative field despite stringent skin preparation and aseptic protocols, likely reflecting endogenous colonization rather than environmental contamination. Although its clinical impact appears limited in this context, the bacteria’s biofilm-forming potential and underrecognized presence in the operating room underscore the importance of continued surveillance and careful interpretation when isolated from surgical specimens. Full article

This work involved the laboratory modeling of biogenic and biogenically mediated corrosion of AISI 304 stainless steel under geochemical conditions representative of the geological disposal of radioactive waste at the Yeniseisky site (Russia). Experiments with a single glucose stimulation of a microbial community sampled from a depth of 450 m established that the initial dominance of organotrophic microflora (primarily genera such as Xanthobacterium, Novosphingobium, Hydrogenophaga, and Pseudomonas) during the first stage (up to 30 days) led to the formation of a microbial biofilm. This biofilm resulted in uniform surface corrosion at a rate of up to 16 µm/year, which is more than 30 times higher than the corrosion rate in the abiotic control. This acceleration is attributed to the accumulation of microbial metabolites, including acetate, ethanol, formate, succinate, n-butyrate, and lactate. The subsequent development of chemotrophic iron- and sulfur-cycling microflora (dominated by genera such as Sideroxydans, Pseudomonas, Geobacter, Desulfuromonas, Desulfovibrio, and Desulfomicrobium) during the second stage of microbial succession (days 60–120) led to the formation of a pit density 10 times greater than that in the abiotic control. It is important to note that the maximum corrosion rates and pit densities were observed upon the addition of a mixture of glucose and sulfate. An assessment of the role of various microbial metabolites and medium components using the potentiodynamic method demonstrated that the combined presence of hydrocarbonate, sulfide, and microbial metabolites in the solution caused a more than fivefold increase in the corrosion current. Thus, the results demonstrate the complex nature of corrosion processes under conditions modeling the geological disposal of radioactive waste, where biological and abiotic factors interact, creating a synergistic effect that significantly enhances corrosion. Full article

N-tetradecanoyl-L-homoserine lactone (C₁₄-HSL) is a long-chain signaling molecule belonging to acyl-homoserine lactones (AHLs), which is widely present in the quorum sensing (QS) system of Gram-negative bacteria. In this study, the effects of C₁₄-HSL on chalcopyrite bioleaching mediated by Acidithiobacillus ferrooxidans (A. ferrooxidans) were investigated. After cultivating A. ferrooxidans with different energy substrates and exploring the potential mechanisms of signal molecule production, chalcopyrite was selected as the energy substrate for further study. Molecular docking analysis revealed that the high binding affinity between AHL and the receptor protein AfeR in A. ferrooxidans was beneficial for the activation of transcription by the AfeR-AHL complex, promoting their biological impact. The variations in the physicochemical parameters of pH, redox potential, and copper ions revealed that after adding C₁₄-HSL, the leaching rate of chalcopyrite increased (1.15 times during the initial 12 days). Further analysis of the mechanism of extracellular polymers formation indicated that the presence of C₁₄-HSL could promote the formation of biofilms and the adhesion of bacteria, facilitating mineral leaching rate of A. ferrooxidans. This research provides a theoretical basis for regulating the biological leaching process of chalcopyrite and metal recovery using signaling molecules, which could also be used to control environmental damage caused by acid mine/rock drainage. Full article