Search Results (522)

Microbial fermentation of plant-derived materials is increasingly recognized as a strategy to enhance biological activity through phytochemical bioconversion. In this study, we investigated the antibiofilm effects of fermented Zingiber officinale rhizome extract against major periodontal pathogens and examined the underlying mechanisms. Ginger extract fermented with plant-derived lactic acid bacteria showed significantly greater inhibition of biofilm formation by Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans than non-fermented extract. The inhibitory activity increased with fermentation time, resulting in approximately 60–70% reduction in biofilm formation at higher concentrations. Chromatographic analysis revealed decreased 6-gingerol and increased 6-shogaol levels after fermentation, suggesting bioconversion of 6-gingerol to 6-shogaol. Direct treatment with 6-shogaol inhibited biofilm formation in a dose-dependent manner in all tested pathogens. Quantitative PCR analysis further showed that 6-shogaol significantly downregulated the quorum sensing-related gene luxS and multiple adhesion- and virulence-associated genes, including flp, fimA, mfa1, radD, fadA, ltxA, and rgpB. These findings indicate that lactic acid bacterial fermentation enhances the antibiofilm activity of ginger extract through increased 6-shogaol production, highlighting its potential as a natural anti-biofilm and anti-virulence agent for periodontal disease prevention and management. Full article

Chronic wounds represent a growing global healthcare burden driven by persistent inflammation, polymicrobial biofilm formation, impaired tissue regeneration, and increased antimicrobial resistance. This review examines the mechanistic interplay between chronic wound pathophysiology, biofilm persistence, and antimicrobial peptide (AMP)-based therapeutics, with particular emphasis on translational barriers and advanced biomaterial-enabled delivery strategies. Current evidence demonstrates that AMPs exert multifactorial activities extending beyond direct antimicrobial effects, including membrane disruption, quorum-sensing inhibition, extracellular polymeric substance (EPS) destabilization, immune modulation, angiogenic stimulation, and promotion of re-epithelialization. However, their clinical translation remains limited due to proteolytic degradation, poor stability, cytotoxicity, rapid clearance, and inadequate retention within the hostile chronic wound microenvironment. To address these limitations, emerging biomaterial platforms—including hydrogels, electrospun nanofibers, nanoparticles, self-assembling peptide systems, and stimuli-responsive smart dressings—have been developed to improve AMP stability, controlled release, biofilm penetration, and regenerative efficacy. This review further highlights current preclinical and clinical challenges, including the lack of standardized polymicrobial biofilm models and translationally relevant wound systems, while discussing future perspectives such as artificial intelligence-assisted peptide design and precision wound therapeutics. We argue that peptide discovery is no longer the principal bottleneck: the rate-limiting steps are now peptide stabilization, biofilm-targeted delivery, and dosing, and no current platform yet couples validated eradication of mature polymicrobial biofilms with validated tissue regeneration in a clinically representative model. Collectively, AMP-enabled smart biomaterials may support the transition from passive wound management toward responsive, biofilm-targeted regenerative therapy. Full article

One of the most pressing challenges facing healthcare today is the rise of biofilm infections and antibiotic-resistant bacteria, which demand entirely new therapeutic strategies beyond conventional antibiotic reliance. A biofilm is a structured community of microorganisms encased in a self-produced extracellular polymeric substance (EPS) matrix, which confers resistance to host immune defenses and antimicrobial agents. Accumulating evidence demonstrates that plant-derived secondary metabolites—including flavonoids, phenolic acids, tannins, terpenoids, and alkaloids—exert potent antibacterial and antibiofilm activities through diverse mechanisms of action. These natural compounds inhibit biofilm formation by disrupting bacterial adhesion, suppressing quorum sensing, degrading the EPS matrix, and impairing bacterial motility. Beyond independent bioactivity, phytochemicals demonstrate significant synergistic potential when combined with conventional antibiotics, revitalizing antimicrobial efficacy against drug-resistant pathogens. Nanoformulation and biogenic carrier technologies further enhance the bioavailability and therapeutic potency of these compounds. Despite these advances, critical challenges persist, including poor bioavailability, physicochemical instability, dose-dependent toxicity, and the risk of resistance development. This review presents a critical and integrative analysis of the pharmacological mechanisms of plant secondary metabolites, with particular emphasis on their role in combating biofilm-associated infections and antibiotic resistance, and discusses translational opportunities including structure–activity relationship (SAR)-guided optimization, high-throughput screening platforms, and advanced drug delivery systems. Collectively, plant secondary metabolites represent a scientifically compelling and clinically relevant pipeline for the development of next-generation antimicrobial and antibiofilm therapeutics. Full article

Marine biofouling on aquaculture netting compromises mass transfer and structural performance, particularly in high-fouling marine environments. Here, a biomimetic antifoulant based on a butenolide scaffold was synthesized and incorporated into silicone coatings to achieve effective antifouling performance. The antifoulant exhibited bactericidal activity against Escherichia coli, Vibrio harveyi, and Staphylococcus aureus, while coating characterization showed increased hydrophobicity and reduced water uptake with minimal loss of adhesion. Algal attachment assays revealed significant inhibition of Isochrysis zhanjiangensis, with an optimal loading of 8 wt%. Notably, planktonic algal growth remained largely unaffected, indicating a surface-mediated mechanism. Mechanistically, the antifoulant is proposed to interfere with quorum sensing-regulated microbial behavior, thereby suppressing initial colonization and biofilm formation. Field immersion tests over six months confirmed sustained antifouling performance with low fouling coverage and stable coating integrity. These findings demonstrate a promising strategy for environmentally compatible biofouling control in offshore aquaculture. Full article

Background/Objectives: Antimicrobial resistance (AMR), microbiota disruption, and chronic inflammation have intensified the search for alternative and complementary antimicrobial strategies. Probiotics and plant-derived bioactive compounds (phytochemicals) are increasingly being investigated as microbiota-supporting, immunomodulatory, and antimicrobial agents. This review synthesizes the current evidence on probiotic–phytochemical interactions, with particular emphasis on mechanisms relevant to antimicrobial synergy, gut barrier reinforcement, microbiota modulation, and translational development. Methods: A narrative literature review with a structured search strategy was conducted using major scientific databases, including PubMed, Scopus, EBSCO, Google Scholar, SpringerLink, Wiley Online Library, and Taylor & Francis, and open repositories. Publications from January 2016 to April 2026 were considered, with an emphasis on experimental, preclinical, clinical, and mechanistic studies addressing the combined use of probiotics, postbiotics, plant extracts, or defined phytochemicals. Results: Available evidence indicates that selected probiotic–phytochemical combinations may enhance antimicrobial activity through complementary mechanisms, including pathogen membrane destabilization, inhibition of adhesion and biofilm formation, quorum-sensing interference, stimulation of probiotic viability and metabolite production, and biotransformation of phytochemicals into more active derivatives. These interactions may also support epithelial barrier integrity and immune regulation. However, the evidence remains heterogeneous and is strongly influenced by probiotic strain identity, phytochemical composition, dose, formulation, and the experimental model. Most studies are still limited to in vitro or animal models, and clinical validation remains scarce. Conclusions: Probiotic–phytochemical combinations represent a promising but insufficiently standardized strategy for antimicrobial and microbiota-targeted interventions. Future progress requires chemically characterized plant preparations, strain-level probiotic selection, harmonized synergy assays, advanced delivery systems, and well-designed clinical trials. Full article

Lactic acid bacteria (LAB), particularly members of the genus Lactobacillus, have emerged as promising biological agents with antimicrobial and anti-biofilm properties. While numerous individual studies have reported their inhibitory effects against pathogenic microorganisms, a systematic understanding that integrates their functional components, molecular mechanisms, and material-based applications remains lacking. In this review, we provide a comprehensive and component-oriented overview of LAB-mediated antimicrobial strategies. We first summarize secreted factors, including organic acids, bacteriocins, hydrogen peroxide, and extracellular vesicles, which collectively contribute to direct pathogen inhibition and environmental modulation. We then discuss cell-associated components such as surface-layer proteins and exopolysaccharides, highlighting their roles in adhesion interference and competitive exclusion. In addition, we examine whole-cell effects, including niche competition, quorum sensing disruption, and host immune modulation. Importantly, we place particular emphasis on the anti-biofilm activity of lactobacilli, detailing mechanisms involved in the prevention of the pathogen initial adhesion, disruption of extracellular polymeric substance matrices, and destabilization of mature biofilms. Finally, we explore emerging strategies that integrate lactobacilli with biomaterials, particularly hydrogel-based systems, to achieve controlled delivery, enhanced stability, and sustained antimicrobial activity. These biohybrid approaches represent a promising direction for the development of next-generation antimicrobial materials. These findings support the concept of LAB-based living antimicrobial materials as a next-generation strategy to combat biofilm-associated infections. Overall, this review aims to bridge the gap between molecular functions and translational applications of lactobacilli, providing new insights into its potential as a versatile platform for antimicrobial and anti-biofilm interventions. Full article

Background: The World Health Organization has identified the growing ineffectiveness of antibiotics against resistant pathogens as a global threat to public health, linked to increased morbidity and mortality. In this context, Pseudomonas aeruginosa stands out as a multidrug-resistant, biofilm-forming pathogen whose biofilm formation increases its tolerance to antimicrobials, which has driven the development of anti-virulence strategies as a therapeutic alternative. In this regard, the present study aimed to evaluate extracts and compounds from Piper species in assays targeting the inhibition of biofilm and virulence factors in Pseudomonas aeruginosa, as well as their anti-quorum sensing activity using Chromobacterium violaceum as a biosensor model. Methods: For this purpose, quorum sensing interference was first assessed through inhibition of violacein production using C. violaceum ATCC 12472 as a biosensor model. The modulation of virulence-associated phenotypes in P. aeruginosa ATCC BAA-47 was subsequently examined through inhibition of biofilm formation by crystal violet staining and spectrophotometric quantification of elastase, protease and pyocyanin production. Results: It was found that extracts from P. aduncum, P. sucrense, P. grande, and P. cumanense inhibited biofilm formation in P. aeruginosa and showed potential activity against quorum sensing in the C. violaceum model, while P. ceanothifolium exhibited only antibiofilm activity. Furthermore, hydroquinone-type compounds and benzoic acid derivatives reduced biofilm formation and virulence factors in P. aeruginosa. Conclusions: The results obtained demonstrate antibiofilm and anti-virulence activity, as well as a possible modulation of quorum sensing in model systems, suggesting that Piper species represent a promising source of bioactive compounds. Full article

Background/Objectives: Numerous natural compounds have been reported to exhibit anti-virulence properties against pathogenic bacteria. Particularly, plants constitute a rich source of anti-quorum-sensing (QS) and anti-biofilm compounds with highly diverse chemical structures. Notably, several studies reported that plant-derived pentacyclic triterpenoids exert anti-biofilm activity against Pseudomonas aeruginosa without affecting bacterial viability, suggesting that this class of naturally occurring chemical compounds may represent a source of potent and clinically relevant anti-biofilm agents. Methods: To further investigate this hypothesis, we evaluated several commercially available pentacyclic triterpenoid acids of the oleanane, ursane and lupane types for their potential impact on QS mechanisms and biofilm formation in the P. aeruginosa PAO1 model strain. Results: Oleanane-type (oleanolic acid and maslinic acid), ursane-type (ursolic acid and corosolic acid) and lupane-type (betulinic acid) triterpenoids inhibited the expression of the QS-regulated lasB and rhlA genes as well as biofilm formation, without affecting bacterial growth. Among tested compounds, oleanolic and ursolic acids, at 400 µM, exhibited the strongest anti-biofilm activities, with 45% and 40% inhibition, respectively. Fluorescence microscopy revealed a marked disorganization of biofilm architectures, with bacterial communities failing to establish compact cell-to-cell attachment and confluent microcolonies. Further analyses indicated that these triterpenoid acids did not affect the expression of QS-regulator genes (lasR/I and rhlR/I), suggesting that their impact on lasB and rhlA expression and biofilm formation is independent of the las and rhl systems. Conclusions: These findings suggest that oleanane and ursane triterpenoid acids represent promising chemical backbones for the development of strategies aimed at inhibiting P. aeruginosa biofilm formation. Full article

(1) Background: The increasing antibiotic resistance of pathogens is necessitating new therapies that target virulence factors. Virulence factors include biofilm formation, which is a key pathogenic factor involved in bacterial pathogenicity and resistance. (2) Methods: Initially, biofilm formation assays were performed to screen the biofilm formation inhibition effects of gastrodin. A bacterial growth assay was performed to examine the synergistic effects and qRT-PCR was performed to identify the underlying molecular regulatory mechanisms. (3) Results: Gastrodin inhibits biofilm formation by bacteria such as E. faecalis (IC₅₀ = 1.56 μg/mL), E. faecium (IC₅₀ = 0.19 μg/mL), S. aureus (IC₅₀ = 6.25 μg/mL), C. acnes (IC₅₀ = 0.78 μg/mL), S. sobrinus (IC₅₀ = 12.5 μg/mL), P. aeruginosa (IC₅₀ = 25.00 μg/mL), and E. coli (IC₅₀ = 25. 10 μg/mL) without directly affecting bacterial growth, as shown by bacterial growth assay. Gastrodin also reduced the expression of cytolysin genes (cylLS, cylR2, and cylM), quorum sensing genes (fsrB, fsrC, gelE, ebpA, ebpB, acm, scm, and bps) and biofilm virulence genes (esp) as shown by qRT-PCR analysis and exhibited dramatic synergistic antibacterial effects in the growth assay. (4) Conclusions: These results suggest that gastrodin may be a promising novel antibacterial adjuvant for biofilm-related bacterial infections, but further experiments, including in vivo assays, are still needed. Full article

Pseudomonas aeruginosa, an opportunistic pathogen, is a major threat to hospital infection control and global public health due to its strong environmental adaptability, complex virulence systems, efficient biofilm formation capability, and widespread multidrug resistance. Traditional single-target antibiotics are often inadequate for clinical treatment. The research into Plant-Derived Bioactive Compounds for combating P. aeruginosa infections is reviewed, highlighting their advantages (many of which are extensively studied in Traditional Chinese Medicine) over conventional antibiotics. The antimicrobial mechanisms of these compounds include the inhibition of bacterial quorum sensing (QS) systems to suppress virulence factor expression rather than direct anti-bactericidal effects, delaying the development of resistance. The abundant natural medicinal plants and their diverse chemical structures provide ample material for active compound screening to identify unique chemical compositions with specific binding to pathogen targets. Plant-Derived Bioactive Compounds exhibit excellent safety profiles, targeting bacterial-specific pathways or host immune regulation, resulting in minimal off-target toxicity. Plant-Derived Bioactive Compounds exert anti-P. aeruginosa effects via inhibition of QS systems to reduce pathogenicity by disrupting intercellular signaling, suppressing biofilm formation/maturity to overcome biofilm-associated resistance, directly interacting with bacterial structure. Plant-Derived Bioactive Compounds are promising treatments for drug-resistant P. aeruginosa infections, providing lead compounds for novel anti-infective drug development. Full article

Bacterial–fungal interactions are prevalent in microbial communities, and fungi often facilitate bacterial dispersal along networks created by fungal hyphae. Using a microfluidic device, we examined how diverse bacterial species disperse in monoculture versus travel in coculture with Aspergillus flavus. Most of the bacteria traveled further when in coculture, although this was not absolute. Two bacteria showing significant dispersal rates only in coculture were the human pathogens Listeria monocytogenes and Staphylococcus aureus. Mechanistically, L. monocytogenes dispersal required flagella, with dispersal impaired in flagellar mutants but enhanced in ∆mogR strains that upregulate flagellar expression. In contrast, the non-flagellar bacterium S. aureus exhibited a unique, wave-like dispersal pattern along the hyphae, a phenomenon that was abolished in agr quorum-sensing mutants deficient in phenol-soluble modulins (PSMs). In a triculture of L. monocytogenes, S. aureus, and A. flavus, L. monocytogenes limited S. aureus dispersal along the fungal hyphae; however, this inhibition was dependent on an intact L. monocytogenes quorum system. Our findings reveal that bacterial motility on fungal networks arises from diverse, species-specific mechanisms, including flagella, transcriptional regulation, potential quorum-sensing-mediated interactions, as well as other notable dispersal phenomena that warrant further investigation. Full article

Antimicrobial resistance (AMR) is one of the most serious threats to global public health, driven in part by extensive antibiotic use in food-producing animals. The poultry industry, a major contributor to the global animal protein supply, has depended on antibiotics for growth promotion and disease control, thereby contributing to the emergence and dissemination of AMR zoonotic bacteria. This review synthesizes current evidence on the potential of phytochemicals (PCs), plant-derived bioactive compounds, as sustainable non-antibiotic alternatives for controlling bacterial foodborne pathogens in poultry. Relevant literature including in vitro and in vivo studies assessing PCs against major poultry-associated zoonotic bacteria, including Salmonella enterica, Campylobacter spp., Clostridium perfringens, Listeria monocytogenes, and pathogenic Escherichia coli, is examined. Evidence indicates that PCs exert antimicrobial and anti-virulence effects through mechanisms like bacterial membrane disruption, inhibition of quorum sensing and virulence gene expression, modulation of gut microbiota, and enhancement of host immune responses. In vivo studies demonstrate reductions in pathogen colonization and improvements in gut health and performance metrics in poultry. Despite these promising findings, challenges remain in bioavailability, dose optimization, standardization, and regulatory approval. Overall, PCs represent a promising component of integrated antimicrobial stewardship strategies in poultry production, with significant implications for mitigating zoonotic AMR transmission. Full article

Periodontal disease is a chronic inflammatory condition driven by polymicrobial biofilms whose interaction with the host immune response drives the destruction of tooth-supporting tissues. Within these communities, bacterial cell–cell communication—particularly quorum sensing (QS)—coordinates virulence factor expression, biofilm maturation, and interspecies behaviour, allowing pathogens to mount population-dependent attacks on the host. Disrupting these signals has therefore drawn growing attention as an anti-virulence strategy for biofilm-associated oral infection. Quorum quenching (QQ)—the inhibition or disruption of QS pathways—prevents bacteria from coordinating these virulence-related activities. The candidate inhibitors investigated to date fall into three broad classes: conventional antibiotics used at sub-inhibitory concentrations, plant-derived natural compounds, and synthetic molecules designed to interfere with signal synthesis, signal reception, or signal transduction. In experimental work on periodontal pathogens, agents from each class reduce biofilm formation, suppress virulence factor production, and disrupt microbial communication within polymicrobial biofilms. Clinical translation, however, lags behind the laboratory evidence. Most data still come from in vitro systems and animal models, and the ecological complexity of the oral biofilm makes therapeutic targeting difficult: signals that drive virulence in pathogens also support cooperation among commensals. Toxicity profiles, pharmacokinetics, and well-powered clinical trials are needed before quorum-quenching agents can be considered for routine periodontal care. Even with these caveats, targeting bacterial communication offers a different therapeutic logic from conventional antimicrobials: attenuating virulence rather than killing cells, and so exerting weaker selective pressure for resistance. Further dissection of QS networks in oral biofilms—and the rational design of quenching agents that act on pathogenic rather than commensal signalling—may yield useful adjuncts to current periodontal therapy. Full article

Biofilm formation constitutes a major factor in antibiotic treatment failure, shielding bacteria from drugs and promoting persistence. This study demonstrates that the anti-biofilm action of clove oil enhances the efficacy of fosfomycin against Escherichia coli O157:H7 (E. coli O157). Using a luxS-eGFP reporter system, it was found that clove oil inhibited E. coli O157 biofilm formation by up to 80% via suppression of the LuxS/AI-2 quorum sensing (QS) system and bacterial motility. Crucially, this disruption was shown to correlate with a strong synergistic effect when combined with fosfomycin in vitro. In a murine peritoneal infection model, the combination therapy demonstrated superior efficacy compared to monotherapy. Specifically, bacterial loads in the liver, spleen, and small intestine were significantly reduced, and histopathological damage was alleviated. Mechanistically, these effects were linked to the downregulation of the QS. These findings indicate that clove oil acts as a potent adjuvant to fosfomycin by disrupting biofilms, offering a promising strategy against systemic infections caused by E. coli O157. Full article

In intensive animal production, the overuse of antibiotics has exacerbated bacterial antimicrobial resistance and environmental pollution. Together with gut microbiota dysbiosis and recurrent disease outbreaks, these challenges severely constrain the sector’s high-quality development. Quorum sensing (QS), a cell-density-dependent bacterial communication mechanism, can be modulated through agents that specifically inhibit or activate QS circuitry to regulate microbial community functions. Such QS modulators possess notable advantages, such as environmental benignity and high target specificity, and thus offer innovative strategies to decrease antibiotic reliance, enhance production efficiency, and reduce environmental emissions. This review examines QS modulators sourced from plants, microorganisms, animals, and synthetic processes, while highlighting key challenges such as environmental interference, resistance development, high costs, and the lack of standardized biosafety evaluations. Future research should focus on enhancing specificity, stability, affordability, and safety, with an emphasis on rational design, synergistic systems, improved manufacturing processes, and multi-target modulators. This review may provide a theoretical basis for translating QS-regulation technologies into farm-level applications, thereby advancing sustainable animal production and antibiotic-free husbandry. Full article