Search Results (589)

The genus Lavandula represents one of the most valuable aromatic and medicinal plants, holding significant economic importance in the pharmaceutical, food, perfumery, and cosmetics industries. Among them, L. multifida is a traditionally used medicinal plant in the Mediterranean region. This work provides a comprehensive review of L. multifida, focusing on its traditional uses, phytochemistry, and pharmacological properties. Unlike conventional lavenders, its essential oil is dominated by phenolic monoterpenes, principally carvacrol, alongside significant concentrations of β-bisabolene, 1,8-cineole, and camphor. This distinct phytochemical profile is further complemented by a rich range of non-volatile constituents, including flavonoids, phenolic acids, and triterpenoids. Pharmacological investigations have validated its broad-spectrum antimicrobial activity, demonstrating efficacy against multidrug-resistant bacterial strains and fungal pathogens through mechanisms such as membrane disruption, metabolic interference, and quorum sensing inhibition. Furthermore, the species exhibits significant antioxidant and anti-inflammatory properties, mediated primarily through radical scavenging, cyclooxygenase inhibition, and cytokine modulation. Owing to its distinct chemistry, specific traditional uses for respiratory and digestive ailments, limited endemic habitat, and underexplored status, L. multifida presents a promising candidate for future research with high potential for novel drug discovery, particularly in antiparasitic and respiratory therapies. This review concludes by identifying key research priorities for L. multifida, including a detailed analysis of its non-volatile compounds, mechanistic elucidation, toxicological assessments, and standardization of extracts. Addressing these gaps is essential to validate its traditional applications and advance its development into evidence-based phytomedicines, adjuvant therapies, and natural agrochemicals. Full article

This study, grounded in traveling wave theory, develops a cross-scale reaction-diffusion model to describe nutrient-dependent bacterial growth on agar surfaces and applies it to in silico investigations of microbial population dynamics. The approach is based on the coupling of a modified Allen–Cahn equation with the formulation of quorum sensing signal dynamics, incorporating a nutrient-dependent regulatory threshold and stochastic diffusion. A closed-loop model of bacterial growth regulated by quorum sensing is developed through theoretical analysis, numerical simulations, and computational experiments.The model is implemented using Yanenko’s computational scheme, which incorporates corrective refinement via Heun’s method to account for nonlinear components. Numerical simulations are carried out in MATLAB, allowing for accurate computation of spatio-temporal patterns and facilitating the identification of key mechanisms governing the collective behavior of bacterial communities. Full article

The global escalation of antimicrobial resistance (AMR) among Gram-negative bacteria poses a severe threat to public health. Traditional antibiotic development struggles to keep pace with emerging resistant strains, necessitating innovative strategies to enhance therapeutic options. This review explores the potential of drug repurposing as a strategic approach to combat Gram-negative bacterial infections, focusing on clinically approved drugs with antibacterial properties or the capacity to enhance antibiotic efficacy through direct or host-directed mechanisms. Within the review, a special section is dedicated to the potential usage of repurposed drugs against bacteria that can be used as biological warfare agents, exposure to which may lead to mass casualties, in particular if these pathogens are resistant to antibiotics. Repurposed drugs exhibit diverse antibacterial mechanisms, including membrane disruption, efflux pump inhibition, iron metabolism interference, quorum sensing suppression, and biofilm inhibition. Additionally, many agents demonstrated host-directed therapeutic effects by modulating inflammatory responses, enhancing autophagy, or boosting innate immune functions. Drug repurposing offers a promising avenue to mitigate the AMR crisis by providing rapid, cost-effective therapeutic solutions. Combining repurposed drugs with existing antibiotics or employing them as host-directed therapies holds significant potential for treating infections caused by multidrug-resistant Gram-negative pathogens. Continued research and clinical validation are essential to translate these findings into effective treatment regimens. Full article

Bacteriophages (phages) play a pivotal role in shaping microbial communities and driving bacterial evolution. Among the diverse mechanisms governing phage–host interactions, the Arbitrium (ARM) communication system represents a recently discovered paradigm in phage decision-making between the lytic and lysogenic cycles. Initially identified in Bacillus-infecting phages, the ARM system employs a quorum-sensing-like peptide signaling mechanism to modulate infection dynamics and optimize population-level survival strategies. Recent studies have elucidated the structural and functional basis of ARM regulation, highlighting its potential applications in antimicrobial therapy, microbiome engineering, and synthetic biology. The significance of ARM systems lies in their ability to regulate bacterial population stability and influence the evolutionary trajectories of microbial ecosystems. Despite being a relatively recent discovery, ARM systems have garnered considerable attention due to their role in decoding phage population dynamics at the molecular level and their promising biotechnological applications. This review synthesizes current advancements in understanding ARM systems, including their molecular mechanisms, ecological implications, and translational potential. By integrating recent findings, we provide a comprehensive framework to guide future research on phage–host communication and its potential for innovative therapeutic strategies. Full article

The emergence of bacterial strains resistant to available antibiotics due to overprescription has prompted a search for alternative treatments. Among the most promising is baicalin, a flavonoid extracted from the roots of Scutellaria baicalensis. Roots, the primary natural source of baicalin, have been extensively explored using emerging extraction technologies such as ultrasonic-assisted extraction and supercritical fluid extraction. These methods offer significant advantages over traditional reflux extraction for baicalin preparation, including shorter extraction times, lower energy consumption, and improved environmental sustainability. Baicalin exhibits remarkable antibacterial activity in vitro and has demonstrated therapeutic efficacy against gastrointestinal infections, meningitis, pulmonary diseases, and sepsis, among other infectious disorders, in animal models. Documented mechanisms of action include disrupting the Escherichia coli membrane, downregulating quorum-sensing gene expression in Pseudomonas aeruginosa, and inhibiting host inflammatory pathways such as PI3K/Akt/NF-κB. However, its clinical translation faces several bottlenecks, including reliance on animal experiment data, low bioavailability, and regulatory compliance issues. This review compares baicalin extraction yields from different natural sources, summarizes the advantages and disadvantages of various extraction technologies, analyzes possible mechanisms of action in treating different bacterial diseases, and discusses outstanding challenges and best strategies for expanded clinical use against bacterial infection. Our aim is to provide a valuable reference for future research and clinical applications. Full article

Microbial reduction in hexavalent chromium (Cr(VI)) is a well characterized bioremediation strategy, yet the mechanistic diversity among bacterial taxa necessitates detailed investigations into strain-specific pathways. Here, we report the isolation and characterization of Bacillus safensis BSF-4, a halophilic bacterium derived from saline-alkali soil, which demonstrates efficient Cr(VI) reduction capacity. Physiological assays showed that BSF-4 achieved 89.15% reduction of 20 mg/L Cr(VI) within 72 h, with Cr(III) identified as the primary extracellular end product. Resting cell assays and subcellular fractionation analyses confirmed that Cr(VI) reduction predominantly occurs in the extracellular milieu. X-ray photoelectron spectroscopy (XPS) further revealed soluble Cr(III) complexed with extracellular polymeric substances (EPS). Transcriptomic profiling indicated upregulation of membrane-associated transport systems (facilitating Cr(VI) exclusion) and quorum sensing (QS) pathways (mediating adaptive stress responses). These findings highlight a dual mechanism: (1) extracellular enzymatic reduction mediated by EPS-bound redox proteins, and (2) intracellular detoxification via QS-regulated defense pathways. Collectively, Bacillus safensis BSF-4 exhibits robust Cr(VI) reduction capacity under saline conditions, positioning it as a promising candidate for bioremediation of Cr(VI)-contaminated saline soils and aquatic ecosystems. Full article

Molecularly imprinted polymers (MIPs) have emerged as promising materials for selectively targeting biomolecules, including quorum sensing autoinducers that regulate bacterial communication and biofilm formation. In this study, both single-template and dual-template strategies were employed to design and synthesize MIPs capable of capturing autoinducer-2 analogs using (3R,4S)-tetrahydro-3,4-furandiol (T1) or (R/S) 2,2-dimethyl-1,3-dioxolane-4-methanol (T2) as the templates. This approach offers translational potential of a complementary or non-antibiotic strategy to conventional antimicrobial therapies in mitigating biofilm-associated infections. Computational modeling guided the rational selection of functional monomers, predicting favorable interaction energies (ΔE_C up to −135 kcal·mol⁻¹) and optimal hydrogen-bonding patterns to enhance template–polymer affinity. The synthesized MIPs were characterized using spectroscopic and microscopic techniques to confirm imprinting efficiency and structural integrity. The adsorption capacity measurements demonstrated higher adsorption capacity and selectivity of MIPs compared to non-imprinted polymers, with the highest selectivity equal to 3.36 for T1 and 3.14 for T2 on MIPs fabricated from methacrylic acid. Preliminary microbiological evaluations using Chromobacterium violaceum ATCC 12472 reveal that the MIPs prepared from 2-hydroxyethyl methacrylate effectively inhibited violacein production by up to 78.2% at 5.0 mg·mL⁻¹, consistent with quorum sensing interference. These findings highlight the feasibility of employing molecular imprinting to target autoinducer-2 analogs, introducing a novel synthetic strategy for disrupting bacterial communication. This further suggests that molecular imprinting can be leveraged to develop potent quorum-sensing inhibitors, an approach that offers translational potential as an alternative to conventional antimicrobial strategies to mitigate biofilm-associated infections. Full article

Biofilms are complex microbial communities embedded in a self-produced extracellular polymeric matrix. These structures confer increased resistance/tolerance to antimicrobial agents and immune responses, posing a serious challenge in both clinical and industrial contexts. In response to these challenges, increasing attention has been given to the development of novel antibiofilm strategies. Among the promising alternatives are lectins—carbohydrate-binding proteins. This review explores the structural and functional features of biofilms and critically discusses recent studies reporting the antibiofilm effects of lectins. Additionally, it addresses the main challenges and limitations surrounding the practical application of lectins to combat biofilms. Lectins from plants, animals, and microorganisms have shown potential to inhibit biofilm formation by disrupting the extracellular matrix, modulating quorum sensing, and affecting bacterial motility and metabolism. Additionally, they can eradicate established biofilms by degrading the matrix, killing or removing microbial cells, and/or preventing biofilm reformation. Together, the findings reviewed here support the continued investigation of lectins as potential agents against biofilm-associated infections as well as highlight the need to address existing gaps, such as the lack of in vivo studies and limited research on the structure–function relationships of lectins and their antibiofilm activity. Full article

The global rise in antimicrobial resistance poses a major threat to public health, with multidrug-resistant bacterial infections expected to surpass cancer in mortality by 2050. As traditional antibiotic pipelines stagnate, novel therapeutic alternatives are critically needed. Antimicrobial peptides (AMPs), particularly those derived from marine organisms, have emerged as promising antimicrobial candidates due to their broad-spectrum activity, structural diversity, and distinctive mechanisms of action. Unlike conventional antibiotics, AMPs can disrupt microbial membranes, inhibit biofilm formation, and even modulate immune responses, making them highly effective against resistant bacteria. This review highlights the potential of marine AMPs as next-generation therapeutics, emphasizing their efficacy against multidrug-resistant pathogens and biofilm-associated infections. Furthermore, marine AMPs show promise in combating persister cells and disrupting quorum sensing pathways, offering new strategies for tackling chronic infections. Despite their potential, challenges such as production scalability and limited clinical validation remain; nevertheless, the use of new technologies and bioinformatic tools is accelerating the discovery and optimization of these peptides, paving the way for bypassing these challenges. This review consolidates current findings on marine AMPs, advocating for their continued exploration as viable tools in the fight against antimicrobial resistance. Full article

In this study, a series of novel alkoxylated resorcinarenes were synthesized using secondary and tertiary alcohols under mild catalytic conditions involving iminodiacetic acid. Structural characterization, including single-crystal X-ray diffraction, confirmed the successful incorporation of branched alkyl chains and highlighted the influence of substitution patterns on molecular packing. Notably, detailed mass spectrometric analysis revealed that, under specific conditions, the reaction pathway may shift toward the formation of defined oligomeric species with supramolecular characteristics—an observation that adds a new dimension to the synthetic potential of this system. To complement the chemical analysis, selected derivatives were evaluated for biological activity, focusing on bacterial growth and biofilm formation. Using four clinically relevant strains (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis), we assessed both planktonic proliferation (OD₆₀₀) and biofilm biomass (crystal violet assay). Compound 2c (2-pentanol derivative) consistently promoted biofilm formation, particularly in S. aureus and B. subtilis, while having limited cytotoxic effects. In contrast, compound 2e and the DMSO control exhibited minimal impact on biofilm development. The results suggest that specific structural features of the alkoxy chains may modulate microbial responses, potentially via membrane stress or quorum sensing interference. This work highlights the dual relevance of alkoxylated resorcinarenes as both supramolecular building blocks and modulators of microbial behavior. Full article

Pseudomonas aeruginosa poses significant health threats due to its multidrug-resistant profile, particularly affecting immunocompromised individuals. The pathogen’s ability to produce virulence factors and antibiotic-resistant biofilms, orchestrated through quorum-sensing (QS) mechanisms, complicates conventional therapeutic interventions. This review aims to critically assess the potential of anti-QS strategies as alternatives to antibiotics against P. aeruginosa infections. Comprehensive literature searches were conducted using databases such as PubMed, Scopus, and Web of Science, focusing on studies addressing QS inhibition strategies published recently. Anti-QS strategies significantly attenuate bacterial virulence by disrupting QS-regulated genes involved in biofilm formation, motility, toxin secretion, and immune evasion. These interventions reduce the selective pressure for resistance and enhance antibiotic efficacy when used in combination therapies. Despite promising outcomes, practical application faces challenges, including specificity of inhibitors, pharmacokinetic limitations, potential cytotoxicity, and bacterial adaptability leading to resistance. Future perspectives should focus on multi-target QS inhibitors, advanced delivery systems, rigorous preclinical validations, and clinical translation frameworks. Addressing current limitations through multidisciplinary research can lead to clinically viable QS-targeted therapies, offering sustainable alternatives to traditional antibiotics and effectively managing antibiotic resistance. Full article

Biofilms are structured communities of microorganisms encased in a self-produced extracellular matrix, and they represent one of the most widespread forms of microbial life on Earth. Their presence poses serious challenges in both environmental and clinical settings. In natural and industrial systems, biofilms contribute to water contamination, pipeline corrosion, and biofouling. Clinically, biofilm-associated infections are responsible for approximately 80% of all microbial infections, including endocarditis, osteomyelitis, cystic fibrosis, and chronic sinusitis. A particularly critical concern is their colonization of medical devices, where biofilms can lead to chronic infections, implant failure, and increased mortality. Implantable devices, such as orthopedic implants, cardiac pacemakers, cochlear implants, urinary catheters, and hernia meshes, are highly susceptible to microbial attachment and biofilm development. These infections are often recalcitrant to conventional antibiotics and frequently necessitate surgical revision. In the United States, over 500,000 biofilm-related implant infections occur annually, with prosthetic joint infections alone projected to incur revision surgery costs exceeding USD 500 million per year—a figure expected to rise to USD 1.62 billion by 2030. To address these challenges, surface modification of medical devices has emerged as a promising strategy to prevent bacterial adhesion and biofilm formation. This review focuses on recent advances in chemical surface functionalization using non-antibiotic agents, such as enzymes, chelating agents, quorum sensing quenching factors, biosurfactants, oxidizing compounds and nanoparticles, designed to enhance antifouling and mature biofilm eradication properties. These approaches aim not only to prevent device-associated infections but also to reduce dependence on antibiotics and mitigate the development of antimicrobial resistance. Full article

Biofilms are a spontaneously formed slimy matrix of extracellular polymeric substances (EPS) enveloping miniature bacterial colonies, which aid in pathogen colonization, shielding the bacteria from antibiotics, as well as imparting them resistance towards the same. Biofilms employ a robust communication mechanism called quorum sensing that serves to keep their population density constant. What is most significant about biofilms is that they contribute to the development of bacterial virulence by providing protection to pathogenic species, allowing them to colonize the host, and also inhibiting the activities of antimicrobials on them. They grow on animate surfaces (such as on teeth and intestinal mucosa, etc.) and inanimate objects (like catheters, contact lenses, pacemakers, endotracheal devices, intrauterine devices, and stents, etc.) alike. It has been reported that as much as 80% of human infections involve biofilms. Serious implications of biofilms include the necessity of greater concentrations of antibiotics to treat common human infections, even contributing to antimicrobial resistance (AMR), since bacteria embedded within biofilms are protected from the action of potential antibiotics. This review explores various contemporary strategies for controlling biofilms, focusing on their modes of action, mechanisms of drug resistance, and innovative approaches to find a solution in this regard. This review interestingly targets the extracellular polymeric matrix as a highly effective strategy to counteract the potential harm of biofilms since it plays a critical role in biofilm formation and significantly contributes to antimicrobial resistance. Full article

This review explores the biofilm architecture and drug resistance of Enterococcus faecalis in clinical and environmental settings. The biofilm in E. faecalis is a heterogeneous, three-dimensional, mushroom-like or multilayered structure, characteristically forming diplococci or short chains interspersed with water channels for nutrient exchange and waste removal. Exopolysaccharides, proteins, lipids, and extracellular DNA create a protective matrix. Persister cells within the biofilm contribute to antibiotic resistance and survival. The heterogeneous architecture of the E. faecalis biofilm contains both dense clusters and loosely packed regions that vary in thickness, ranging from 10 to 100 µm, depending on the environmental conditions. The pathogenicity of the E. faecalis biofilm is mediated through complex interactions between genes and virulence factors such as DNA release, cytolysin, pili, secreted antigen A, and microbial surface components that recognize adhesive matrix molecules, often involving a key protein called enterococcal surface protein (Esp). Clinically, it is implicated in a range of nosocomial infections, including urinary tract infections, endocarditis, and surgical wound infections. The biofilm serves as a nidus for bacterial dissemination and as a reservoir for antimicrobial resistance. The effectiveness of first-line antibiotics (ampicillin, vancomycin, and aminoglycosides) is diminished due to reduced penetration, altered metabolism, increased tolerance, and intrinsic and acquired resistance. Alternative strategies for biofilm disruption, such as combination therapy (ampicillin with aminoglycosides), as well as newer approaches, including antimicrobial peptides, quorum-sensing inhibitors, and biofilm-disrupting agents (DNase or dispersin B), are also being explored to improve treatment outcomes. Environmentally, E. faecalis biofilms contribute to contamination in water systems, food production facilities, and healthcare environments. They persist in harsh conditions, facilitating the spread of multidrug-resistant strains and increasing the risk of transmission to humans and animals. Therefore, understanding the biofilm architecture and drug resistance is essential for developing effective strategies to mitigate their clinical and environmental impact. Full article

Nosocomial infections caused by ESKAPE pathogens represent a significant burden to global health. These pathogens may exhibit multidrug resistance (MDR) mechanisms, of which mechanisms such as efflux pumps and biofilm formation are gaining significant importance. Multidrug resistance mechanisms in ESKAPE pathogens have led to an increase in the effective costs in health care and a higher risk of mortality in hospitalized patients. These pathogens utilize antimicrobial efflux pump mechanisms and bacterial biofilm-forming capabilities to escape the bactericidal action of antimicrobials. ESKAPE bacteria forming colonies demonstrate increased expression of efflux pump-encoding genes. Efflux pumps not only expel antimicrobial agents but also contribute to biofilm formation by bacteria through (1) transport of molecules and transcription factors involved in biofilm quorum sensing, (2) bacterial fimbriae structure transport for biofilm adhesion to surfaces, and (3) regulation of a transmembrane gradient to survive the difficult conditions of biofilm microenvironments. The synergistic role of these mechanisms complicates treatment outcomes. Given the mechanistic link between biofilms and efflux pumps, therapeutic strategies should focus on targeting anti-biofilm mechanisms alongside efflux pump inactivation with efflux pump inhibitors. This review explores the molecular interplay between efflux pumps and biofilm formation, emphasizing potential therapeutic strategies such as efflux pump inhibitors (EPIs) and biofilm-targeting agents. Full article