ADJUVANTS - Word Related Documents




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905000.9768Cationic Polysaccharide Conjugates as Antibiotic Adjuvants Resensitize Multidrug-Resistant Bacteria and Prevent Resistance. In recent years, traditional antibiotic efficacy has rapidly diminished due to the advent of multidrug-resistant (MDR) bacteria, which poses severe threat to human life and globalized healthcare. Currently, the development cycle of new antibiotics cannot match the ongoing MDR infection crisis. Therefore, novel strategies are required to resensitize MDR bacteria to existing antibiotics. In this study, novel cationic polysaccharide conjugates Dextran-graft-poly(5-(1,2-dithiolan-3-yl)-N-(2-guanidinoethyl)pentanamide) (Dex-g-PSS(n) ) is synthesized using disulfide exchange polymerization. Critically, bacterial membranes and efflux pumps are disrupted by a sub-inhibitory concentration of Dex-g-PSS(30) , which enhances rifampicin (RIF) accumulation inside bacteria and restores its efficacy. Combined Dex-g-PSS(30) and RIF prevents bacterial resistance in bacteria cultured over 30 generations. Furthermore, Dex-g-PSS(30) restores RIF effectiveness, reduces inflammatory reactions in a pneumonia-induced mouse model, and exhibits excellent in vivo biological absorption and degradation capabilities. As an antibiotic adjuvant, Dex-g-PSS(30) provides a novel resensitizing strategy for RIF against MDR bacteria and bacterial resistance. This Dex-g-PSS(30) research provides a solid platform for future MDR applications.202235962720
843710.9758Tocopherol polyethylene glycol succinate-modified hollow silver nanoparticles for combating bacteria-resistance. Multiple drug resistance and the increase in the appearance of superbugs together with the exceedingly scant development of new potent antibiotic drugs pose an urgent global medical threat and imminent public security crisis. In the present study, we fabricated well-dispersed tocopherol polyethylene glycol succinate (TPGS)-capped silver nanoparticles (AgNPs) of about 10 nm in size. The hollow structure of the TPGS-capped AgNPs (TPGS/AgNPs) was confirmed and applied to load antibiotics. The TPGS/AgNPs proved to be able to cross the bacterial cell wall and penetrate into bacteria, thereby delivering more of the antibiotic to the interior of bacteria and thus enhancing the in vitro antibacterial effect of the antibiotic, even overcoming the drug-resistance in drug-resistant E. coli and Acinetobacter baumannii. It was found that the TPGS modification in the TPGS/AgNPs could decrease the activity of the efflux pumps AdeABC and AdeIJK in drug-resistant Acinetobacter baumannii via inhibiting the efflux pump genes adeB and adeJ, thus increasing the accumulation of the delivered antibiotic and overcoming the drug-resistance. Tigecycline delivered by TPGS/AgNPs could effectively antagonize drug-resistance in an acute peritonitis model mice, thereby increasing the survival rate and alleviating the inflammatory response. TPGS/AgNPs were developed as a novel and effective antibiotic delivery system and TPGS was demonstrated to have great potential as a pharmaceutical excipient for use in drug-resistant infection therapy.201930968093
600820.9757Photopolymerized keratin-PGLa hydrogels for antibiotic resistance reversal and enhancement of infectious wound healing. Infectious wounds have become serious challenges for both treatment and management in clinical practice, so development of new antibiotics has been considered an increasingly difficult task. Here, we report the design and synthesis of keratin 31 (K31)-peptide glycine-leucine-amide (PGLa) photopolymerized hydrogels to rescue the antibiotic activity of antibiotics for infectious wound healing promotion. K31-PGLa displayed an outstanding synergistic effect with commercial antibiotics against drug-resistant bacteria by down-regulating the synthesis genes of efflux pump. Furthermore, the photopolymerized K31-PGLa/PEGDA hydrogels effectively suppressed drug-resistant bacteria growth and enhanced skin wound closure in murine. This study provided a promising alternative strategy for infectious wound treatment.202337810750
843630.9753NIR-Activated Hydrogel with Dual-Enhanced Antibiotic Effectiveness for Thorough Elimination of Antibiotic-Resistant Bacteria. Antibiotic resistance has become a critical health crisis globally. Traditional strategies using antibiotics can lead to drug-resistance, while inorganic antimicrobial agents can cause severe systemic toxicity. Here, we have developed a dual-antibiotic hydrogel delivery system (PDA-Ag@Levo/CMCS), which can achieve controlled release of clinical antibiotics levofloxacin (Levo) and classic nanoscale antibiotic silver nanoparticles (AgNPs), effectively eliminating drug-resistant P. aeruginosa. Benefiting from the photothermal (PTT) effect of polydopamine (PDA), the local high temperature generated by PDA-Ag@Levo/CMCS can quickly kill bacteria through continuous and responsive release of dual-antibiotics to restore sensitivity to ineffective antibiotics. Moreover, AgNPs could significantly improve the efficiency of traditional antibiotics by disrupting bacterial membranes and reducing their toxicity to healthy tissues. A clever combination of PTT and drug-combination therapy can effectively eliminate biofilms and drug-resistant bacteria. Mechanism studies have shown that PDA-Ag@Levo might eliminate drug-resistant P. aeruginosa by disrupting biofilm formation and protein synthesis, and inhibit the resistance mutation of P. aeruginosa by promoting the expression of related genes, such as rpoS, dinB, and mutS. Collectively, the synergistic effect of this dual-antibiotic hydrogel combined with PTT provides a creative strategy for eliminating drug-resistant bacteria in chronic infection wounds.202539760335
922140.9751Breaking antimicrobial resistance by disrupting extracytoplasmic protein folding. Antimicrobial resistance in Gram-negative bacteria is one of the greatest threats to global health. New antibacterial strategies are urgently needed, and the development of antibiotic adjuvants that either neutralize resistance proteins or compromise the integrity of the cell envelope is of ever-growing interest. Most available adjuvants are only effective against specific resistance proteins. Here, we demonstrate that disruption of cell envelope protein homeostasis simultaneously compromises several classes of resistance determinants. In particular, we find that impairing DsbA-mediated disulfide bond formation incapacitates diverse β-lactamases and destabilizes mobile colistin resistance enzymes. Furthermore, we show that chemical inhibition of DsbA sensitizes multidrug-resistant clinical isolates to existing antibiotics and that the absence of DsbA, in combination with antibiotic treatment, substantially increases the survival of Galleria mellonella larvae infected with multidrug-resistant Pseudomonas aeruginosa. This work lays the foundation for the development of novel antibiotic adjuvants that function as broad-acting resistance breakers.202235025730
916050.9750Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective. Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS) to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs), as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs) to block the action of AIs and quorum quenching (QQ) enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.201829563876
815860.9749Nanobioconjugates: Weapons against Antibacterial Resistance. The increase in drug resistance in pathogenic bacteria is emerging as a global threat as we swiftly edge toward the postantibiotic era. Nanobioconjugates have gained tremendous attention to treat multidrug-resistant (MDR) bacteria and biofilms due to their tunable physicochemical properties, drug targeting ability, enhanced uptake, and alternate mechanisms of drug action. In this review, we highlight the recent advances made in the use of nanobioconjugates to combat antibacterial resistance and provide crucial insights for designing nanomaterials that can serve as antibacterial agents for nanotherapeutics, nanocargos for targeted antibiotic delivery, or both. Also discussed are different strategies for treating robust biofilms formed by bacteria.202035019602
816170.9747Integrative strategies against multidrug-resistant bacteria: Synthesizing novel antimicrobial frontiers for global health. Concerningly, multidrug-resistant bacteria have emerged as a prime worldwide trouble, obstructing the treatment of infectious diseases and causing doubts about the therapeutic accidentalness of presently existing drugs. Novel antimicrobial interventions deserve development as conventional antibiotics are incapable of keeping pace with bacteria evolution. Various promising approaches to combat MDR infections are discussed in this review. Antimicrobial peptides are examined for their broad-spectrum efficacy and reduced ability to develop resistance, while phage therapy may be used under extreme situations when antibiotics fail. In addition, the possibility of CRISPR-Cas systems for specifically targeting and eradicating resistance genes from bacterial populations will be explored. Nanotechnology has opened up the route to improve the delivery system of the drug itself, increasing the efficacy and specificity of antimicrobial action while protecting its host. Discovering potential antimicrobial agents is an exciting prospect through developments in synthetic biology and the rediscovery of natural product-based medicines. Moreover, host-directed therapies are now becoming popular as an adjunct to the main strategies of therapeutics without specifically targeting pathogens. Although these developments appear impressive, questions about production scaling, regulatory approvals, safety, and efficacy for clinical employment still loom large. Thus, tackling the MDR burden requires a multi-pronged plan, integrating newer treatment modalities with existing antibiotic regimens, enforcing robust stewardship initiatives, and effecting policy changes at the global level. The international health community can gird itself against the growing menace of antibiotic resistance if collaboration between interdisciplinary bodies and sustained research endeavours is encouraged. In this study, we evaluate the synergistic potential of combining various medicines in addition to summarizing recent advancements. To rethink antimicrobial stewardship in the future, we provide a multi-tiered paradigm that combines pathogen-focused and host-directed strategies.202540914328
843580.9747Antimicrobial Zeolitic Imidazolate Frameworks with Dual Mechanisms of Action. The horizontal transfer of drug-resistant genes and the formation of biofilm barriers have threatened the therapeutic efficacy of conventional antibiotic drugs. Development of non-antibiotic agents with high delivery efficiency through bacterial biofilms is urgently required. A pyrithione (PT)-loading zeolitic imidazolate framework (ZIF-8@PT) is synthesized to destroy biofilms and improve the sensitivity of bacteria to PT. ZIF-8@PT can target and destroy the biofilm as well as the cell membrane, promoting the intracellular delivery of PT and possibly its interaction with SmpB, a protein that could regulate the drug resistance of bacteria. ZIF-8@PT effectively suppresses abdominal infections induced by multiresistant Aeromonas veronii C4 in rodent models without systemic toxicity. ZIF-8@PT promises wide applications in treating infections caused by multidrug-resistant bacteria through a dual mechanism of action.202336815744
902290.9746Drug repositioning: doxazosin attenuates the virulence factors and biofilm formation in Gram-negative bacteria. The resistance development is an increasing global health risk that needs innovative solutions. Repurposing drugs to serve as anti-virulence agents is suggested as an advantageous strategy to diminish bacterial resistance development. Bacterial virulence is controlled by quorum sensing (QS) system that orchestrates the expression of biofilm formation, motility, and virulence factors production as enzymes and virulent pigments. Interfering with QS could lead to bacterial virulence mitigation without affecting bacterial growth that does not result in bacterial resistance development. This study investigated the probable anti-virulence and anti-QS activities of α-adrenoreceptor blocker doxazosin against Proteus mirabilis and Pseudomonas aeruginosa. Besides in silico study, in vitro and in vivo investigations were conducted to assess the doxazosin anti-virulence actions. Doxazosin significantly diminished the biofilm formation and release of QS-controlled Chromobacterium violaceum pigment and virulence factors in P. aeruginosa and P. mirabilis, and downregulated the QS encoding genes in P. aeruginosa. Virtually, doxazosin interfered with QS proteins, and in vivo protected mice against P. mirabilis and P. aeruginosa. The role of the membranal sensors as QseC and PmrA was recognized in enhancing the Gram-negative virulence. Doxazosin downregulated the membranal sensors PmR and QseC encoding genes and could in silico interfere with them. In conclusion, this study preliminary documents the probable anti-QS and anti-virulence activities of doxazosin, which indicate its possible application as an alternative or in addition to antibiotics. However, extended toxicological and pharmacological investigations are essential to approve the feasible clinical application of doxazosin as novel efficient anti-virulence agent. KEY POINTS: • Anti-hypertensive doxazosin acquires anti-quorum sensing activities • Doxazosin diminishes the virulence of Proteus mirabilis and Pseudomonas aeruginosa • Doxazosin could dimmish the bacterial espionage.202337079062
9157100.9744Potential Emergence of Multi-quorum Sensing Inhibitor Resistant (MQSIR) Bacteria. Expression of certain bacterial genes only at a high bacterial cell density is termed as quorum-sensing (QS). Here bacteria use signaling molecules to communicate among themselves. QS mediated genes are generally involved in the expression of phenotypes such as bioluminescence, biofilm formation, competence, nodulation, and virulence. QS systems (QSS) vary from a single in Vibrio spp. to multiple in Pseudomonas and Sinorhizobium species. The complexity of QSS is further enhanced by the multiplicity of signals: (1) peptides, (2) acyl-homoserine lactones, (3) diketopiperazines. To counteract this pathogenic behaviour, a wide range of bioactive molecules acting as QS inhibitors (QSIs) have been elucidated. Unlike antibiotics, QSIs don't kill bacteria and act at much lower concentration than those of antibiotics. Bacterial ability to evolve resistance against multiple drugs has cautioned researchers to develop QSIs which may not generate undue pressure on bacteria to develop resistance against them. In this paper, we have discussed the implications of the diversity and multiplicity of QSS, in acting as an arsenal to withstand attack from QSIs and may use these as reservoirs to develop multi-QSI resistance.201626843692
9159110.9744Quorum sensing inhibitors (QSIs): a patent review (2019-2023). INTRODUCTION: The collective behavior of bacteria is regulated by Quorum Sensing (QS), in which bacteria release chemical signals and express virulence genes in a cell density-dependent manner. Quorum Sensing inhibitors (QSIs) are a large class of natural and synthetic compounds that have the potential to competitively inhibit the Quorum Sensing (QS) systems of several pathogens blocking their virulence mechanisms. They are considered promising compounds to deal with antimicrobial resistance, providing an opportunity to develop new drugs against these targets. AREAS COVERED: The present review represents a comprehensive analysis of patents and patent applications available on Espacenet and Google Patent, from 2019 to 2023 referring to the therapeutic use of Quorum Sensing inhibitors. EXPERT OPINION: Unlike classical antibiotics, which target the basic cellular metabolic processes, QSIs provide a promising alternative to attenuating virulence and pathogenicity without putting selective pressure on bacteria. The general belief is that QSIs pose no or little selective pressure on bacteria since these do not affect their growth. To date, QSIs are seen as the most promising alternative to traditional antibiotics. The next big step in this area of research is its succession to the clinical stage.202540219759
9222120.9744Bacterial proton motive force as an unprecedented target to control antimicrobial resistance. Novel antibacterial therapies are urgently required to tackle the increasing number of multidrug-resistant pathogens. Identification of new antimicrobial targets is critical to avoid possible cross-resistance issues. Bacterial proton motive force (PMF), an energetic pathway located on the bacterial membrane, crucially regulates various biological possesses such as adenosine triphosphate synthesis, active transport of molecules, and rotation of bacterial flagella. Nevertheless, the potential of bacterial PMF as an antibacterial target remains largely unexplored. The PMF generally comprises electric potential (ΔΨ) and transmembrane proton gradient (ΔpH). In this review, we present an overview of bacterial PMF, including its functions and characterizations, highlighting the representative antimicrobial agents that specifically target either ΔΨ or ΔpH. At the same time, we also discuss the adjuvant potential of bacterial PMF-targeting compounds. Lastly, we highlight the value of PMF disruptors in preventing the transmission of antibiotic resistance genes. These findings suggest that bacterial PMF represents an unprecedented target, providing a comprehensive approach to controlling antimicrobial resistance.202336896761
9164130.9741Quorum quenching: role of nanoparticles as signal jammers in Gram-negative bacteria. Quorum sensing (QS) is a cell density dependent regulatory process that uses signaling molecules to manage the expression of virulence genes and biofilm formation. The study of QS inhibitors has emerged as one of the most fascinating areas of research to discover novel antimicrobial agents. Compounds that block QS have become candidates as unusual antimicrobial agents, as they are leading players in the regulation of virulence of drug-resistant pathogens. Metal and metal oxide nanoparticles offer novel alternatives to combat antibiotic resistance in Gram-negative bacteria aiming their capacity as QS inhibitors. This review provides an insight into the quorum quenching potential of metal and metal oxide nanoparticles by targeting QS regulated virulence of Gram-negative bacteria.201930539663
8432140.9741A 0D-2D Heterojunction Bismuth Molybdate-Anchored Multifunctional Hydrogel for Highly Efficient Eradication of Drug-Resistant Bacteria. Due to the increasing antibiotic resistance and the lack of broad-spectrum antibiotics, there is an urgent requirement to develop fresh strategies to combat multidrug-resistant pathogens. Herein, defect-rich bismuth molybdate heterojunctions [zero-dimensional (0D) Bi(4)MoO(9)/two-dimensional (2D) Bi(2)MoO(6), MBO] were designed for rapid capture of bacteria and synergistic photocatalytic sterilization. The as-prepared MBO was experimentally and theoretically demonstrated to possess defects, heterojunctions, and irradiation triple-enhanced photocatalytic activity for efficient generation of reactive oxygen species (ROS) due to the exposure of more active sites and separation of effective electron-hole pairs. Meanwhile, dopamine-modified MBO (pMBO) achieved a positively charged and rough surface, which conferred strong bacterial adhesion and physical penetration to the nanosheets, effectively trapping bacteria within the damage range and enhancing ROS damage. Based on this potent antibacterial ability of pMBO, a multifunctional hydrogel consisting of poly(vinyl alcohol) cross-linked tannic acid-coated cellulose nanocrystals (CPTB) and pMBO, namely CPTB@pMBO, is developed and convincingly effective against methicillin-resistant Staphylococcus aureus in a mouse skin infection model. In addition, the strategy of combining a failed beta-lactam antibiotic with CPTB@pMBO to photoinactivation with no resistance observed was developed, which presented an idea to address the issue of antibiotic resistance in bacteria and to explore facile anti-infection methods. In addition, CPTB@pMBO can reduce excessive proteolysis of tissue and inflammatory response by regulating the expression of genes and pro-inflammatory factors in vivo, holding great potential for the effective treatment of wound infections caused by drug-resistant bacteria.202337531599
8159150.9740Quaternary Ammonium Salts: Insights into Synthesis and New Directions in Antibacterial Applications. The overuse of antibiotics has led to the emergence of a large number of antibiotic-resistant genes in bacteria, and increasing evidence indicates that a fungicide with an antibacterial mechanism different from that of antibiotics is needed. Quaternary ammonium salts (QASs) are a biparental substance with good antibacterial properties that kills bacteria through simple electrostatic adsorption and insertion into cell membranes/altering of cell membrane permeability. Therefore, the probability of bacteria developing drug resistance is greatly reduced. In this review, we focus on the synthesis and application of single-chain QASs, double-chain QASs, heterocyclic QASs, and gemini QASs (GQASs). Some possible structure-function relationships of QASs are also summarized. As such, we hope this review will provide insight for researchers to explore more applications of QASs in the field of antimicrobials with the aim of developing systems for clinical applications.202336748912
9155160.9739Polyphenols and their nanoformulations as potential antibiofilm agents against multidrug-resistant pathogens. The emergence of multidrug-resistant (MDR) pathogens is a major problem in the therapeutic management of infectious diseases. Among the bacterial resistance mechanisms is the development of an enveloped protein and polysaccharide-hydrated matrix called a biofilm. Polyphenolics have demonstrated beneficial antibacterial effects. Phenolic compounds mediate their antibiofilm effects via disruption of the bacterial membrane, deprivation of substrate, protein binding, binding to adhesion complex, viral fusion blockage and interactions with eukaryotic DNA. However, these compounds have limitations of chemical instability, low bioavailability, poor water solubility and short half-lives. Nanoformulations offer a promising solution to overcome these challenges by enhancing their antibacterial potential. This review summarizes the antibiofilm role of polyphenolics, their underlying mechanisms and their potential role as resistance-modifying agents.202438305223
8176170.9738Overcoming Multidrug Resistance in Bacteria Through Antibiotics Delivery in Surface-Engineered Nano-Cargos: Recent Developments for Future Nano-Antibiotics. In the recent few decades, the increase in multidrug-resistant (MDR) bacteria has reached an alarming rate and caused serious health problems. The incidence of infections due to MDR bacteria has been accompanied by morbidity and mortality; therefore, tackling bacterial resistance has become an urgent and unmet challenge to be properly addressed. The field of nanomedicine has the potential to design and develop efficient antimicrobials for MDR bacteria using its innovative and alternative approaches. The uniquely constructed nano-sized antimicrobials have a predominance over traditional antibiotics because their small size helps them in better interaction with bacterial cells. Moreover, surface engineering of nanocarriers offers significant advantages of targeting and modulating various resistance mechanisms, thus owe superior qualities for overcoming bacterial resistance. This review covers different mechanisms of antibiotic resistance, application of nanocarrier systems in drug delivery, functionalization of nanocarriers, application of functionalized nanocarriers for overcoming bacterial resistance, possible limitations of nanocarrier-based approach for antibacterial delivery, and future of surface-functionalized antimicrobial delivery systems.202134307323
8799180.9738The membrane-active polyaminoisoprenyl compound NV716 re-sensitizes Pseudomonas aeruginosa to antibiotics and reduces bacterial virulence. Pseudomonas aeruginosa is intrinsically resistant to many antibiotics due to the impermeability of its outer membrane and to the constitutive expression of efflux pumps. Here, we show that the polyaminoisoprenyl compound NV716 at sub-MIC concentrations re-sensitizes P. aeruginosa to abandoned antibiotics by binding to the lipopolysaccharides (LPS) of the outer membrane, permeabilizing this membrane and increasing antibiotic accumulation inside the bacteria. It also prevents selection of resistance to antibiotics and increases their activity against biofilms. No stable resistance could be selected to NV716-itself after serial passages with subinhibitory concentrations, but the transcriptome of the resulting daughter cells shows an upregulation of genes involved in the synthesis of lipid A and LPS, and a downregulation of quorum sensing-related genes. Accordingly, NV716 also reduces motility, virulence factors production, and biofilm formation. NV716 shows a unique and highly promising profile of activity when used alone or in combination with antibiotics against P. aeruginosa, combining in a single molecule anti-virulence and potentiator effects. Additional work is required to more thoroughly understand the various functions of NV716.202236008485
9158190.9736Quorum sensing pathways in Gram-positive and -negative bacteria: potential of their interruption in abating drug resistance. Quorum sensing (QS) is an inter-cell communication between bacterial populations through release of tiny diffusible compounds as signalling agents, called auto-inducers, abetting bacteria to track population density. QS allows bacterial population to perform collectively in coordination to wide phenotypes like alterations in expression of virulence genes to achieve advancement over their competitors, drug resistance and biofilm formation. Several classes of autoinducers have been described that are involved in bacterial virulence. This review gives an insight into the multitudinous QS systems in Gram-positive and Gram-negative bacteria to explore their role in microbial physiology and pathogenesis. Bacterial resistance to antibiotics has clinically become a super challenge. Strategies to interrupt QS pathways by natural and synthetic QS inhibitors or quorum quenchers or analogs provide a potential treatment. We highlight the advancements in discovery of promising new targets for development of next generation antimicrobials to control infections caused by multidrug resistant bacterial pathogens.201931007147