Nano-Strategies to Fight Multidrug Resistant Bacteria-"A Battle of the Titans"

Neutering pathogens through green synthesized nanoparticles

The rise of multidrug-resistant (MDR) pathogens in animal diseases poses a severe threat to veterinary care and public health, necessitating the development of alternative therapeutic strategies. Traditional antimicrobial treatments are becoming increasingly less effective, creating an urgent need for innovative solutions. One among several other promising avenues is the use of plant-based nanoparticles (NPs), which exhibit powerful antimicrobial properties while offering a sustainable and low-toxicity approach. These nanoparticles, synthesized via green methods using plant-derived phytochemicals as natural reducing and stabilizing agents, provide an eco-friendly, cost-effective, and biocompatible option for addressing MDR pathogens. Additionally, the physicochemical properties of these nanoparticles, including size, shape, and surface characteristics, can be fine-tuned to enhance their antimicrobial potency and target-specific action. This review explores the potential of plant-based nanoparticles as a groundbreaking strategy for tackling MDR pathogens in animal diseases, focusing on their mechanisms of action, green synthesis techniques, and applications in veterinary medicine. By optimizing synthesis processes, assessing toxicity, and evaluating in vivo efficacy, plant-based nanoparticles could emerge as an essential tool in the fight against antimicrobial resistance (AMR) in animals, with implications for global health.

Nanomaterial-based drug delivery systems in overcoming bacterial resistance: Current review

Antimicrobial resistance is one of the most serious contemporary global health concerns, threatening the effectiveness of existing antibiotics and resulting in morbidity, mortality, and economic burdens. This review examines the contribution of nanomaterial-based drug delivery systems to solving the problems associated with bacterial resistance and provides a thorough overview of their mechanisms of action, efficiency, and perspectives for the future. Owing to their unique physicochemical properties, nanomaterials reveal new ways of passing through the traditional mechanisms of bacterial defence connected to the permeability barrier of membranes, efflux pumps, and biofilm formation. This review addresses the different types of nanomaterials, including metallic nanoparticles, liposomes, and polymeric nanoparticles, in terms of their antimicrobial properties and modes of action. More emphasis has been placed on the critical discussion of recent studies on such active systems. Both in vitro and in vivo models are discussed, with particular attention paid to multidrug-resistant bacteria. This review begins by reviewing the urgency for antimicrobial resistance (AMR) by citing recent statistics, which indicate that the number of deaths and reasons for financial losses continue to increase. A background is then provided on the limitations of existing antibiotic therapies and the pressing need to develop innovative approaches. Nanomaterial-based drug delivery systems have been proposed as promising solutions because of their potential to improve drug solubility, stability, and targeted delivery, although side effects can also be mitigated. In addition to established knowledge, this review also covers ongoing debates on the continuous risks associated with the use of nanomaterials, such as toxicity and environmental impact. This discussion emphasizes the optimization of nanomaterial design to target specific bacteria, and rigorous clinical trials to establish safety and efficacy in humans. It concludes with reflections on the future directions of nanomaterial-based drug delivery systems in fighting AMR, underlining the need for an interdisciplinary approach, along with continuous research efforts to translate these promising technologies into clinical practice. As the fight against bacterial resistance reaches its peak, nanomaterials may be the key to developing next-generation antimicrobial therapies.

Green Biosynthesis of Bimetallic Copper Oxide-Selenium Nanoparticles Using Leaf Extract of Lagenaria Siceraria: Antibacterial, Anti-Virulence Activities Against Multidrug-Resistant Pseudomonas Aeruginosa

Introduction

Clinical isolates of Pseudomonas aeruginosa (P. aeruginosa) are among the most recovered bacteria with phenotypic antimicrobial resistance. Bimetallic nanoparticles (BNPs) have received much attention for antimicrobial activity in the last decade. This research aimed to biosynthesize bimetallic copper oxide-selenium nanoparticles (CuO-Se BNPs) and to assess its bioactivity on various P. aeruginosa clinical isolates.

Methodology

Based on the possible synergistic effects, CuO-Se BNPs were selected and biosynthesized using leaf extract of Lagenaria siceraria (L. siceraria) for the first time. The obtained BNPs were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and transmission and scanning electron microscopes. The capability of Cu-Se BNPs to cease the growth of P. aeruginosa isolates and to reduce their virulence characters was evaluated. Also, different cell lines were used to assess its cytotoxicity and anticancer activity.

Results

The elemental composition of CuO and Se was revealed by the UV, XRD, and EDX data, indicating the synthesis of CuO-Se core shell BNPs with a size of 50 nm. In well diffusion assay, CuO-Se BNPs P. aeruginosa growth with 10-21 mm inhibition zone diameter and 38-95% inhibition. Also, the minimum inhibitory concentration and minimum bactericidal concentration were in a relatively wide range of 7.8-250 μg/mL and 31.2-500 μg/mL, respectively, with tolerance level range of 2-16. Additionally, CuO-Se BNPs shown anti-pyocyanin activity of 4.35-63.21% inhibition while the anti-proteolytic activity was in a range of 4.96-12.59% and anti-pyoverdine effect was in a range of 0.24-83.41%. The IC50 against Wi-38 normal cells was 267.2 µg/mL while the IC50 were 31.1 and 83.4 µg/mL against MCF-7 and Hep-G2, respectively, indicating promising anticancer activity.

Conclusion

This research demonstrates the promising antibacterial, anti-virulence, and antitumor properties with safe low concentrations of CuO-Se NPs, synthesized via an eco-friendly green synthesis method without the use of toxic chemicals, offering a sustainable and cost-effective alternative.

Nanoparticles of banana peels as a potential source of bioactive compounds and their activities on HepG2

Nanoparticles of blanched green banana peels (BGBP) were prepared using physical technique (by grinding) in order to avoid any harm effect on human health that could occurred when metals were used for preparing nanoparticles size (NPs) of banana peels. This work was designed to study the preparation of nano scale (70-135 nm for TEM) (243.4-933.9 nm for SEM) and normal size (0.12-0.25 µm for TEM) (1.150 µm for SEM) from BGBP after milling and evaluate the activities of their extracts as antioxidant, antimicrobial and anticancer agents. The size and shape of nanoparticles were analyzed using Scanning Electron Microscope (SEM) and it cleared the appearance of particle aggregation was attributed to mechanical pressure and friction resulting from the interaction between the abrasive balls and the pulverizing vessel's inner surface. Also, Transmission Electron Microscope (TEM) shows presence of different spherical shapes ranging between 70 and 135 nm, along with the emergence of slender fibrillary shapes., on the other hand, Fourier transform IR (FT-IR) cleared that the higher extraction yields of phenolic compounds and greater antioxidant activities were achieved due to the increased surface area of nano-scale samples following milling. In addition, X-ray diffraction (XRD) determined the materials crystalline structure. Bioactive compounds (mainly phenolic compounds) were recovered by extracting banana peels weather from normal size or (NPs). The extracted bioactive compounds were subjected to evolution as antioxidant, antimicrobial and anticancer agents. Dealing with this study, it was concluded that bioactive compounds extracted from NPS of BGBP showed antioxidant, antimicrobial and anticancer activities higher than those extracted from the normal size ones. So, it is strongly recommended to use NPs of BGBP for producing these bioactive compounds since these compounds are important to protect humans against a lot of dangerous diseases. Finally, the potential applications of these compounds in the pharmaceutical or food industries would be beneficial.

Nanomedicine approaches to enhance the effectiveness of meropenem: a strategy to tackle antimicrobial resistance

Meropenem, a carbapenem typically reserved for treating severe infections, has encountered resistance from certain bacteria, including multidrug-resistant (MDR) strains of Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumonia (K. pneumonia). Nanoparticles (NPs) have emerged as a promising strategy to combat drug-resistant bacteria. By targeting specific biosynthetic and enzymatic pathways and penetrating bacterial membranes, NPs can function as antibiotic delivery systems (nanocarriers) or exhibit intrinsic antibacterial properties. When combined with various types of nanoparticles-such as lipid- and polymer-based NPs, metallic NPs, silica NPs, nanoemulsions, niosomes, carbon NPs, and nanocomposites-meropenem has shown enhanced effectiveness in overcoming resistance to MDR bacteria and reducing adverse effects. However, several challenges persist, including scaling up industrial production, ensuring safety and favorable toxicity profiles, and addressing the limited availability of in vivo evidence. This review explores nanoparticle strategies to combat resistance to meropenem.

Beyond antibiotics: exploring multifaceted approaches to combat bacterial resistance in the modern era: a comprehensive review

Antibiotics represent one of the most significant medical breakthroughs of the twentieth century, playing a critical role in combating bacterial infections. However, the rapid emergence of antibiotic resistance has become a major global health crisis, significantly complicating treatment protocols. This paper provides a narrative review of the current state of antibiotic resistance, synthesizing findings from primary research and comprehensive review articles to examine the various mechanisms bacteria employ to counteract antibiotics. One of the primary sources of antibiotic resistance is the improper use of antibiotics in the livestock industry. The emergence of drug-resistant microorganisms from human activities and industrial livestock production has presented significant environmental and public health concerns. Today, resistant nosocomial infections occur following long-term hospitalization of patients, causing the death of many people, so there is an urgent need for alternative treatments. In response to this crisis, non-antibiotic therapeutic strategies have been proposed, including bacteriophages, probiotics, postbiotics, synbiotics, fecal microbiota transplantation (FMT), nanoparticles (NPs), antimicrobial peptides (AMPs), antibodies, traditional medicines, and the toxin-antitoxin (TA) system. While these approaches offer innovative solutions for addressing bacterial infections and preserving the efficacy of antimicrobial therapies, challenges such as safety, cost-effectiveness, regulatory hurdles, and large-scale implementation remain. This review examines the potential and limitations of these strategies, offering a balanced perspective on their role in managing bacterial infections and mitigating the broader impact of antibiotic resistance.

A Comprehensive Overview of Antibacterial Agents for Combating Multidrug-Resistant Bacteria: The Current Landscape, Development, Future Opportunities, and Challenges

Background/Objectives: Antimicrobial resistance poses a major public health challenge. The World Health Organization has identified 15 priority pathogens that require prompt development of new antibiotics. This review systematically evaluates the antibacterial resistance of the most significant bacterial pathogens, currently available treatment options, as well as complementary approaches for the management of infections caused by the most challenging multidrug-resistant (MDR) bacteria. For carbapenem-resistant Gram-negative bacteria, treatment options include combinations of beta-lactam antibiotics and beta-lactamase inhibitors, a novel siderophore cephalosporin, known as cefiderocol, as well as older antibiotics like polymixins and tigecycline. Treatment options for Gram-positive bacteria are vancomycin, daptomycin, linezolid, etc. Although the development of new antibiotics has stagnated, various agents with antibacterial properties are currently in clinical and preclinical trials. Non-antibiotic strategies encompass antibiotic potentiators, bacteriophage therapy, antivirulence therapeutics, antimicrobial peptides, antibacterial nanomaterials, host-directed therapy, vaccines, antibodies, plant-based products, repurposed drugs, as well as their combinations, including those used alongside antibiotics. Significant challenges exist in developing new antimicrobials, particularly related to scientific and technical issues, along with policy and economic factors. Currently, most of the alternative options are not part of routine treatment protocols. Conclusions and Future Directions: There is an urgent need to expedite the development of new strategies for treating infections caused by MDR bacteria. This requires a multidisciplinary approach that involves collaboration across research, healthcare, and regulatory bodies. Suggested approaches are crucial for addressing this challenge and should be backed by rational antibiotic use, enhanced infection control practices, and improved surveillance systems for emerging pathogens.

Synergistic antibacterial activity of chitosan-polyethylene glycol nanocomposites films containing ZIF-8 and doxycycline

BACKGROUND

Antibiotic resistance is a growing global threat due to antibiotic overuse and limited treatment options. Multidrug-resistant bacteria, like Staphylococcus aureus and Escherichia coli, increase infection complexity and mortality. This study explores nanocomposite films of ZIF-8 nanoparticles and Doxycycline (Dox) to enhance antibacterial efficacy. In this study, nanocomposite films composed of chitosan (CS) and polyethylene glycol (PEG), incorporating zeolitic imidazolate framework-8 (ZIF-8) nanoparticles and DOX, were developed. These films were characterized by their morphological, mechanical, antibacterial, and drug-release properties. Antibacterial efficacy was evaluated using disk diffusion, broth microdilution, and checkerboard assay methods to determine MICs and potential synergistic effects.

RESULTS

The nanocomposite films demonstrated flexibility, semi-transparency, and a yellowish-brown hue, with films containing ZIF-8 nanoparticles being thicker (79 ± 0.2 μm) than those without (54 ± 0.5 μm). The tensile strength was enhanced with the incorporation of ZIF-8, peaking at 53.12 MPa for the CS-PEG-G-10% DOX-4% ZIF-8 film. XRD analysis confirmed the crystallinity of the ZIF-8 and DOX, with distinct peaks observed for each material. The drug release studies revealed an initial burst followed by sustained release, with higher release rates in acidic environments compared to neutral and alkaline media. The CS-PEG-G-10% DOX-4% ZIF-8 nanocomposite film demonstrated significantly higher antibacterial activity, achieving the lowest MIC values, particularly against S. aureus (22.5 mm inhibition zone) compared to E. coli (14 mm inhibition zone). Additionally, a notable synergistic effect was observed between CS-PEG-G-10% DOX and CS-PEG-G-10% DOX, with FICI values below 0.5.

CONCLUSIONS

The CS-PEG-G-10% DOX-4% ZIF-8 nanocomposite exhibits enhanced antibacterial efficacy and optimal properties, positioning it as a strong candidate for developing effective treatments against multidrug-resistant pathogens.

Staphylococcal Drug Resistance: Mechanisms, Therapies, and Nanoparticle Interventions

The increasing incidence of antibiotic resistance in Staphylococcus aureus (S. aureus) poses a substantial threat to global public health. In recent decades, the evolution of bacteria and the misuse of antibiotics have led to a progressive development in drug resistance of S. aureus, resulting in a worldwide rise in methicillin-resistant S. aureus (MRSA) infection rates. Understanding the molecular mechanisms underlying staphylococcal drug resistance, the treatments for staphylococcal infections, and the efficacy of nanomaterials in addressing multi-drug resistance is crucial. This review explores the resistance mechanisms, which include limiting drug uptake, target modification, drug inactivation through the production of degrading enzymes, and active efflux of drugs. It also examines the current therapeutic strategies, such as antibiotic combination therapy, phage therapy, monoclonal antibody therapy, and nanoparticle therapy, with a particular emphasis on the role of silver-based nanomaterials. Nanoparticles possess the ability to overcome multi-drug resistance, offering a novel avenue for the management of drug-resistant bacteria. The nanomaterials have demonstrated potent antibacterial activity against S. aureus through various mechanisms, including cell membrane disruption, generation of reactive oxygen species (ROS), and inhibition of essential cellular processes. It also highlights the need for further research to optimize nanoparticle design, enhance their antibacterial potency, and ensure their biocompatibility and biodegradability. The review ultimately concludes by emphasizing the importance of a multifaceted approach to treatment, including the development of new antibiotics, investment in stewardship programs to prevent antibiotic misuse, and the exploration of natural compounds and bacteriocins as potential antimicrobial agents.

An Australian perspective on clinical, economic and regulatory considerations in emerging nanoparticle therapies for infections

Antimicrobial resistance (AMR) poses a growing global health threat. Nanomedicine, combined with drug repurposing, may help extend the effective lifespan of current and new antimicrobials. This review, presents an Australian perspective on nanotechnology-based therapies, highlighting scientific and clinical challenges. Early consideration of the potential barriers to market access may help to accelerate research translation, regulatory approval and patient access to nano-antimicrobial (NAM) drugs for resistant pathogens, not only in Australia, but globally.

Frontiers in superbug management: innovating approaches to combat antimicrobial resistance

Anti-microbial resistance (AMR) is a global health issue causing significant mortality and economic burden. Pharmaceutical companies' discontinuation of research hinders new agents, while MDR pathogens or "superbugs" worsen the problem. Superbugs pose a threat to common infections and medical procedures, exacerbated by limited antibiotic development and rapid antibiotic resistance. The rising tide of antimicrobial resistance threatens to undermine progress in controlling infectious diseases. This review examines the global proliferation of AMR, its underlying mechanisms, and contributing factors. The study explores various methodologies, emphasizing the significance of precise and timely identification of resistant strains. We discuss recent advancements in CRISPR/Cas9, nanoparticle technology, light-based techniques, and AI-powered antibiogram analysis for combating AMR. Traditional methods often fail to effectively combat multidrug-resistant bacteria, as CRISPR-Cas9 technology offers a more effective approach by cutting specific DNA sequences, precision targeting and genome editing. AI-based smartphone applications for antibiogram analysis in resource-limited settings face challenges like internet connectivity, device compatibility, data quality, energy consumption, and algorithmic limitations. Additionally, light-based antimicrobial techniques are increasingly being used to effectively kill antibiotic-resistant microbial species and treat localized infections. This review provides an in-depth overview of AMR covering epidemiology, evolution, mechanisms, infection prevention, control measures, antibiotic access, stewardship, surveillance, challenges and emerging non-antibiotic therapeutic approaches.

Adoptive cell transfer of piezo-activated macrophage rescues immunosuppressed rodents from life-threating bacterial infections

Bacterial infections pose a significant threat to human health. Catalytic antibacterial nanoparticles that generate reactive oxygen species (ROS) are emerging, as a promising therapeutic approach in treating bacterial infection by boosting the innate immune defenses. However, the interaction between innate immune cells and these catalytic nanoparticles remains poorly understood. Here, by using rodent models of bacterial infection, we test the antimicrobial properties of ultrasound-responsive piezo-catalytic nanoparticles (piezoNP). We show that piezoNPs strongly interact with macrophages within subcutaneous abscesses caused by Staphylococcus aureus (S. aureus) infections, and demonstrate that this interaction enhances the macrophage-mediated antibacterial phagocytosis and killing activity through intracellular piezocatalysis. Moreover, we test the use of these piezo-activated macrophages (piezoMϕ) as adoptive cell therapy (ACT) for treating various immunosuppressive bacterial infections, including sepsis, pneumonia and peritonitis. Our study thus highlights the potential application of catalytic nanoparticles as a promising alternative to conventional infection treatment to effectively modulate the innate immune responses and to engineer macrophages for immunotherapy purposes.

Current developments and prospects of the antibiotic delivery systems

Antibiotics have remained the cornerstone for the treatment of bacterial infections ever since their discovery in the twentieth century. The uproar over antibiotic resistance among bacteria arising from genome plasticity and biofilm development has rendered current antibiotic therapies ineffective, urging the development of innovative therapeutic approaches. The development of antibiotic resistance among bacteria has further heightened the clinical failure of antibiotic therapy, which is often linked to its low bioavailability, side effects, and poor penetration and accumulation at the site of infection. In this review, we highlight the potential use of siderophores, antibodies, cell-penetrating peptides, antimicrobial peptides, bacteriophages, and nanoparticles to smuggle antibiotics across impermeable biological membranes to achieve therapeutically relevant concentrations of antibiotics and combat antimicrobial resistance (AMR). We will discuss the general mechanisms via which each delivery system functions and how it can be tailored to deliver antibiotics against the paradigm of mechanisms underlying antibiotic resistance.

A Comprehensive Review on Exploring the Potential of Phytochemicals and Biogenic Nanoparticles for the Treatment of Antimicrobial-Resistant Pathogenic Bacteria

Antimicrobial resistance (AMR) is an escalating global health concern that results in approximately 700,000 deaths annually owing to drug-resistant infections. It compromises the effectiveness of conventional antibiotics, as well as fundamental medical procedures, such as surgery and cancer treatment. Phytochemicals, natural plant constituents, and biogenic nanoparticles synthesized through biological processes are pharmacological alternatives for supplementing or replacing traditional antibiotics. These natural compounds exhibit a diverse range of bioactive properties, including antibacterial, anti-inflammatory, and antioxidant activities, and have the potential to overcome bacterial resistance mechanisms. However, their limited solubility, bioavailability, and stability have limited their therapeutic potential. Nanotechnology, particularly the utilization of biogenic nanoparticles, offers the potential to overcome these limitations by enhancing the biosafety, stability, and controlled release of phytochemical compounds, thereby enabling a more effective combination of resistant pathogens. This review examines current research on the combinatorial application of phytochemicals and biogenic nanoparticles, with emphasis on their capacity to address AMR. This study presents a novel perspective on the concurrent utilization of phytochemicals and biogenic nanoparticles, which may enhance antibacterial efficacy while mitigating toxicity. This review provides specific and innovative insights into the novelty, sustainability, and eco-friendly aspects of these approaches to address multidrug-resistant infections, highlighting their role in emerging as a transformative strategy for AMR management through the integration of natural and biogenic resources.

Unveiling the nanoworld of antimicrobial resistance: integrating nature and nanotechnology

A significant global health crisis is predicted to emerge due to antimicrobial resistance by 2050, with an estimated 10 million deaths annually. Increasing antibiotic resistance necessitates continuous therapeutic innovation as conventional antibiotic treatments become increasingly ineffective. The naturally occurring antibacterial, antifungal, and antiviral compounds offer a viable alternative to synthetic antibiotics. This review presents bacterial resistance mechanisms, nanocarriers for drug delivery, and plant-based compounds for nanoformulations, particularly nanoantibiotics (nAbts). Green synthesis of nanoparticles has emerged as a revolutionary approach, as it enhances the effectiveness, specificity, and transport of encapsulated antimicrobials. In addition to minimizing systemic side effects, these nanocarriers can maximize therapeutic impact by delivering the antimicrobials directly to the infection site. Furthermore, combining two or more antibiotics within these nanoparticles often exhibits synergistic effects, enhancing the effectiveness against drug-resistant bacteria. Antimicrobial agents are routinely obtained from secondary metabolites of plants, including essential oils, phenols, polyphenols, alkaloids, and others. Integrating plant-based antibacterial agents and conventional antibiotics, assisted by suitable nanocarriers for codelivery, is a potential solution for addressing bacterial resistance. In addition to increasing their effectiveness and boosting the immune system, this synergistic approach provides a safer and more effective method of tackling future bacterial infections.

Nanozymes as Antibacterial Agents: New Concerns in Design and Enhancement Strategies

Nanozymes exhibiting natural enzyme-mimicking catalytic activities as antibacterial agents present several advantages, including high stability, low cost, broad-spectrum antibacterial activity, ease of preparation and storage, and minimal bacterial resistance. Consequently, they have attracted significant attention in recent years. However, the rapid expansion of antimicrobial nanozyme research has resulted in pioneering reviews that do not comprehensively address emerging concerns and enhancement strategies within this field. This paper first summarizes the factors influencing the intrinsic activity of nanozymes; subsequently, we outline new research considerations for designing antibacterial nanozymes with enhanced functionality and biosafety features such as degradable, imageable, targeted, and bacterial-binding nanozymes as well as those capable of selectively targeting pathogenic bacteria while sparing normal cells and probiotics. Furthermore, we review novel enhancement strategies involving external physical stimuli (light or ultrasound), the introduction of extrinsic small molecules, and self-supplying H2O2 to enhance the activity of antibacterial nanozymes under physiological conditions characterized by low concentrations of H2O2 and O2. Additionally, we present non-redox nanozymes that operate independently of highly toxic reactive oxygen species (ROS) alongside those designed to combat less common pathogenic bacteria. Finally, we discuss current issues, challenges faced in the field, and future prospects for antibacterial nanozymes.

Synergistic Antibacterial Effect of ZnO Nanoparticles and Antibiotics against Multidrug-resistant Biofilm Bacteria

BACKGROUND

The misuse of antibiotics leads to a global increase in antibiotic resistance. Therefore, it is imperative to search for alternative compounds to conventional antibiotics. ZnO nanoparticles (Zn NP) are one of these alternatives because they are an effective option to overcome biofilm bacterial cells and a novel way to overcome multidrug resistance in bacteria. The current research study aims to characterize the efficacy of ZnO nanoparticles alone and in combination with other antibacterial drugs against bacterial biofilms.

METHODS

ZnO NPs were prepared by co-precipitation method, and their anti-biofilm and antibacterial activities alone or combined with four types of broad-spectrum antibacterial (Norfloxacin, Colistin, Doxycycline, and Ampicillin) were evaluated against E. coli and S. aureus bacterial strains. Finally, the cytotoxicity and the hemolytic activity were evaluated.

RESULTS

ZnO NPs were prepared, and results showed that their size was around 10 nm with a spherical shape and a zeta potential of -21.9. In addition, ZnO NPs were found to have a strong antibacterial effect against Gram-positive and Gram-negative microorganisms, with a minimum inhibitory concentration (MIC) of 62.5 and 125 μg/mL, respectively. Additionally, they could eradicate biofilmforming microorganisms at a concentration of 125 μg/m. ZnO NPs were found to be non-toxic to erythrocyte cells. Still, some toxicity was observed for Vero cells at effective concentration ranges needed to inhibit bacterial growth and eradicate biofilm-forming organisms. When combined with different antibacterial, ZnO NP demonstrated synergistic and additive effects with colistin, and the MIC and MBEC of the combination decreased significantly to 0.976 μg/mL against planktonic and biofilm strains of MDR Gram-positive bacteria, resulting in significantly reduced toxicity.

CONCLUSION

The findings of this study encourage the development of alternative therapies with high efficacy and low toxicity. ZnO nanoparticles have demonstrated promising results in overcoming multi-drug resistant bacteria and biofilms, and their combination with colistin has shown a significant reduction in toxicity. Further studies are needed to investigate the potential of ZnO nanoparticles as a viable alternative to conventional antibiotics.

Effectiveness of a Novel Liposomal Methylglyoxal-Tobramycin Formulation in Reducing Biofilm Formation and Bacterial Adhesion

Background: The emergence of multidrug-resistant bacteria presents a significant global health threat. Liposomal antibiotics have shown a potential to improve antibiotic delivery and efficacy. This study aimed to develop liposomes encapsulating tobramycin (TOB) and methylglyoxal (MGO) to enhance TOB activity while reducing bacterial adhesion and biofilm formation. Methods: Clinical isolates of Pseudomonas aeruginosa and Klebsiella pneumoniae were characterized using whole-genome sequencing. Liposomes (Lip-MGO-TOB) were formulated using Manuka honey as a surfactant and loaded with MGO and TOB. Antibacterial activity, biofilm formation, and bacterial cell adhesion assays were performed to compare the efficacy of Lip-MGO-TOB against free TOB. Liposome characterization included analyses of morphology, zeta potential, TOB encapsulation efficiency, and stability under various biological conditions. Results: The Lip-MGO-TOB formulation, at a minimum inhibitory concentration (MIC) of 32 µg/mL, reduced the biofilm formation of the P. aeruginosa isolate (PA85) by 68%. Conversely, free TOB, at a MIC of 64 µg/mL, achieved only a 21% reduction. For the K. pneumoniae isolate (KP57), Lip-MGO-TOB inhibited bacterial adhesion to A549 cells at a lower concentration (256 µg/mL) compared to free TOB (512 µg/mL). Lip-MGO-TOB demonstrated sustained drug release over 24 h under tested conditions and retained over 99% of TOB. Conclusions: The Lip-MGO-TOB formulation significantly enhanced TOB activity against resistant bacteria compared to free TOB. Additionally, it provided a stable drug delivery system with controlled drug release. Liposomal TOB represents a promising advancement in combating antibiotic resistance by improving the efficacy and delivery of conventional antibiotics.

E. coli and S. aureus resist silver nanoparticles via an identical mechanism, but through different pathways

Nanostructured materials with antibacterial activity face the same threat as conventional antibiotics - bacterial resistance, which reduces their effectiveness. However, unlike antibiotics, research into the emergence and mechanisms of bacterial resistance to antibacterial nanomaterials is still in its early stages. Here we show how Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria develop resistance to silver nanoparticles, resulting in an increase in the minimum inhibitory concentration from 1.69 mg/L for S. aureus and 3.38 mg/L for E. coli to 54 mg/L with repeated exposure over 12 and 6 cultivation steps, respectively. The mechanism of resistance is the same for both types of bacteria and involves the aggregation of silver nanoparticles leading to the formation of black precipitates. However, the way in which Gram-positive and Gram-negative bacteria induce aggregation of silver nanoparticles is completely different. Chemical analysis of the surface of the silver precipitates shows that aggregation is triggered by flagellin production in E. coli and by bacterial biofilm formation in S. aureus. However, resistance in both types of bacteria can be overcome by using pomegranate rind extract, which inhibits both flagellin and biofilm production, or by stabilizing the silver nanoparticles by covalently binding them to a composite material containing graphene sheets, which protects the silver nanoparticles from aggregation induced by the bacterial biofilm produced by S. aureus. This research improves the understanding of bacterial resistance mechanisms to nanostructured materials, which differ from resistance mechanisms to conventional antibiotics, and provides potential strategies to combat bacterial resistance and develop more effective antimicrobial treatments.

Immobilization of Silver Nanoparticles with Defensive Gum of Moringa oleifera for Antibacterial Efficacy Against Resistant Bacterial Species from Human Infections

Background: The worldwide misuse of antibiotics is one of the main factors in microbial resistance that is a serious threat worldwide. Alternative strategies are needed to overcome this issue. Objectives: In this study, a novel strategy was adopted to suppress the growth of resistant pathogens through immobilization of silver nanoparticles (AgNPs) in gum of Moringa oleifera. Methods: The AgNPs were prepared from the leaves of Moringa oleifera and subsequently characterized through UV-spectrophotometry, FTIR, SEM, and XRD. The differential ratios of characterized AgNPs were immobilized with gum of M. oleifera and investigated for antimicrobial potential against highly resistant pathogens. Results: The immobilized AgNPs displayed promising activities against highly resistant B. subtilis (23.6 mm; 50 µL:200 µL), E. coli (19.3 mm; 75 µL:200 µL), K. pneumoniae (22 mm; 200 µL:200 µL), P. mirabilis (16.3 mm; 100 µL:200 µL), P. aeruginosa (22 mm; 175 µL:200 µL), and S. typhi (19.3; 25 µL:200 µL) than either AgNPs alone or gum. The immobilized AgNPs released positive sliver ions that easily attached to negatively charged bacterial cells. After attachment and permeation to bacterial cells, the immobilized NPs alter the cell membrane permeability, protein/enzymes denaturation, oxidative stress (ROS), damage DNA, and change the gene expression level. It has been mechanistically considered that the immobilized AgNPs can kill bacteria by damaging their cell membranes, dephosphorylating tyrosine residues during their signal transduction pathways, inducing cell apoptosis, rupturing organelles, and inhibiting cell division, which finally leads to cell death. Conclusions: This study proposes a potential alternative drug for curing various infections.

Restoring vancomycin activity against resistant Enterococcus faecalis using a transcription factor decoy as a vanA operon-inhibitor

BACKGROUND

Vancomycin-resistant enterococci (VRE) represent a public health threat due to the few available treatments. Such alarm has triggered worldwide initiatives to develop effective antimicrobial compounds and novel delivery and therapeutic strategies. vanA operon is responsible for most cases of acquired vancomycin resistance in enterococci.

OBJECTIVES

Development of a transcription factor decoy (TFD) system as a vanA gene transcription-inhibitor.

METHODS

Vancomycin MIC was determined in the presence of TFD-lipoplexes. Additionally, the effect of TFD-lipoplexes on the expression level of the vanA gene and the growth pattern of E. faecalis was evaluated. The haemolytic activity of the developed TFD-lipoplexes and their cytotoxicity were examined. TFD-lipoplexes efficiency in treating vancomycin-resistant E. faecalis (VREF) infection was tested in vivo using a systemic mice infection model.

RESULTS

A reduction in vancomycin MIC against VRE from 256 mg/L (resistant) to 16 mg/L (intermediate susceptible), in the presence of TFD-lipoplexes, was recorded. The developed TFD-lipoplexes lacked any effect on E. faecalis growth and significantly reduced the transcription level of the vanA gene by about 3-fold. In an initial evaluation of the safety of TFD-lipoplexes, they were found not to be overtly haemolytic to human blood or cytotoxic to human skin fibroblast cells. The co-administration of TFD-lipoplexes and vancomycin efficiently eradicated VREF infection in vivo.

CONCLUSIONS

The developed TFD-lipoplexes successfully restored vancomycin activity against VREF. They offer a safe effective unconventional therapy against this stubborn organism and present a revolution in gene therapy that can be applied to other resistance-encoding genes in various organisms.

The Syntheses of Chromium Aluminum Carbide (Cr2AlC) MAX Phase and Cr2CTx MXene and Investigation of Their Antimicrobial Properties

Chromium aluminum carbide (Cr2AlC) MAX phase and Cr2CTx (MXene-Cr) were synthesized by the pressureless sintering method and hydrothermal method, respectively. In addition to this, the free radical scavenging activities (FRSA) of MAX-Cr phase and MXene-Cr compounds were tested and compared with ascorbic acid and trolox as standard compounds. The obtained FRSA results of MAX-Cr phase and MXene-Cr were 42.82 and 59.64%, respectively, at 100 mg/L concentration. MXene-Cr showed a 66.90% inhibitory effect on α-amylase at 200 mg/L. The DNA nuclease activity of compounds was determined to be extremely satisfactory at 50, 100, and 200 mg/L concentrations. Moreover, the prepared MAX-Cr phase and MXene-Cr were investigated for antimicrobial activity against six bacterial and two fungal strains by the broth microdilution method. Compounds provided more significant inhibition against Gram-positive bacteria than Gram-negative bacteria and fungi. MAX-Cr phase and MXene-Cr almost completely inhibited microbial cell viability at a 25 mg/L concentration. Additionally, MXene-Cr showed 89.86% and 87.01% antibiofilm activity against S. aureus and P. aeruginosa, respectively, while the antibiofilm activity of the MAX-Cr phase was over 90%.

Green engineering of NiO nanoparticles decorated with Arachis hypogaea shell extract for biomedical applications

We attempted to synthesize nickel oxide nanoparticles (NiO-NPs) utilizing waste Arachis hypogaea (peanut) shell extract and studied their structural, morphological, and biological performance for biomedical applications. The green engineered NiO-NPs possessed a face-centered cubic structure with an average particle size of 20 nm in highly crystalline form. NiO-NPs were shown to have an optical resonance peak at 327 nm with 3 eV as the optical band gap according to the UV–visible spectra, and the stretching band between Ni–O were evidenced from the FTIR and Raman spectrum. Utilizing green approach the stable nanoparticles were obtained with average particle size of 31 nm from SEM analysis; zeta potential value of −17.6 mV, and PDI as 0.68, revealed the formation of spherical nanoparticles with distinct morphologies without aggregation. XPS analysis confirmed the oxidation states of the elements Ni (2p) and O (1s). This approach may help to increase the surface area, increasing the possibility of nanoparticles interacting with bacterial cells. Furthermore, the presence of nickel and the oxygen oxidation state were confirmed by XPS. Proteus vulgaris, Streptococcus oralis, Bacillus subtilis, and Escherichia coli were found to be susceptible to the antibacterial action of the produced NiO-NPs, with a maximal zone of inhibition of 10.25 mm at 500 μg/ml for P. vulgaris. For P. vulgaris and E. coli, the minimum inhibitory concentrations of NiO were 5.36 and 12.55 %, respectively, at 31.25 μg mL−1. We hereby claim that green engineered NiO NPs decorated with A. hypogaea shell extract have great potential for pharmaceutical and biomedical applications.

Prevention and potential remedies for antibiotic resistance: current research and future prospects

The increasing threat of antibiotic resistance and shrinking treatment options for infections have pushed mankind into a difficult position. The looming threat of the return of the pre-antibiotic era has caused a sense of urgency to protect and conserve the potency of antibiotic therapy. One of the perverse effects of antibiotic resistance is the dissemination of its causative agents from non-clinically important strains to clinically important strains and vice versa. The popular saying "Prevention is better than cure" is appropriate for tackling antibiotic resistance. On the one hand, new and effective antibiotics are required; on the other hand, better measures for the use of antibiotics, along with increased awareness in the general public related to antibiotic use, are essential. Awareness, especially of appropriate antibiotic use, antibiotic resistance, its dissemination, and potential threats, can help greatly in controlling the use and abuse of antibiotics, and the containment of antibiotic resistance. Antibiotic drugs' effectiveness can be enhanced by producing novel antibiotic analogs or adding adjuvants to current antibiotics. Combinatorial therapy of antibiotics has proven successful in treating multidrug-resistant (MDR) bacterial infections. This review aims to highlight the current global situation of antibiotic resistance and discuss the methods used to monitor, prevent, inhibit, or reverse bacterial resistance mechanisms in the fight against antibiotic resistance.

Cellulose from bacteria as a delivery system for improved treatment of infectious diseases: A review of updates and prospects

Cellulose from bacteria is a high-purity biomaterial naturally produced by bacteria as part of their metabolic process. Although it inherently lacks antimicrobial activity, its modification with bioactive substances can significantly enhance its efficacy beyond that of the original compounds. This biomaterial features a unique ability to retain substantial quantities of liquids within its three-dimensional network, making it a prime candidate for biomedical applications. Versatile in its properties, it can be utilized across various industries. Previous research has highlighted its capacity to exhibit antimicrobial properties and to encapsulate nanostructured materials, thereby augmenting its antibacterial effectiveness. This review focuses on the use of cellulose from bacteria as a carrier for active compounds, specifically targeting antibacterial activity against drug-resistant strains. We explore its role in innovative bacterial cellulose-based systems, which present a promising solution for tackling bacterial resistance. This review aims to showcase the potential of bacterial cellulose in developing new devices and treatment strategies that address critical concerns in global health.

Chitosan-Clay Mineral Nanocomposites with Antibacterial Activity for Biomedical Application: Advantages and Future Perspectives

Polymers of natural origin, such as representatives of various polysaccharides (e.g., cellulose, dextran, hyaluronic acid, gellan gum, etc.), and their derivatives, have a long tradition in biomedical applications. Among them, the use of chitosan as a safe, biocompatible, and environmentally friendly heteropolysaccharide has been particularly intensively researched over the last two decades. The potential of using chitosan for medical purposes is reflected in its unique cationic nature, viscosity-increasing and gel-forming ability, non-toxicity in living cells, antimicrobial activity, mucoadhesiveness, biodegradability, as well as the possibility of chemical modification. The intuitive use of clay minerals in the treatment of superficial wounds has been known in traditional medicine for thousands of years. To improve efficacy and overcome the ubiquitous bacterial resistance, the beneficial properties of chitosan have been utilized for the preparation of chitosan-clay mineral bionanocomposites. The focus of this review is on composites containing chitosan with montmorillonite and halloysite as representatives of clay minerals. This review highlights the antibacterial efficacy of chitosan-clay mineral bionanocomposites in drug delivery and in the treatment of topical skin infections and wound healing. Finally, an overview of the preparation, characterization, and possible future perspectives related to the use of these advancing composites for biomedical applications is presented.

Green synthesis of silver and gold-doped zinc oxide nanocomposite with propolis extract for enhanced anticancer activity

Metal and metal oxide nanocomposites have unique properties and are promising for antibacterial and anticancer applications. In this work, we aimed to highlight the relationship between the biosynthesis ways of silver and gold-doped zinc oxide nanocomposites and their functions as anticancer on cell lines (MCF-7 and HepG2). The propolis was used to biosynthesize four different nanoparticles with the same components, including zinc, gold and silver. The nanocomposites were characterized using various techniques, including ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy Dispersive X-ray analysis (EDX) and cytotoxicity assays. The result of this study showed that formed nanocomposites have a similar level of Zn, Au, and Ag, ranging from 23-34%, 2-6%, and 2-3%, respectively. In addition, adding the components simultaneously produces the fastest color change, and the fabricated nanoparticles have spherical shapes with different layers. In addition, the prepared nanoparticles influenced the cell viability of the cancer cell lines, with the most effective one when Zn, Au, and Ag were added spontaneously to form a nanocomposite called (All) with IC50 of 24.5 µg/mL for MCF7 cells and 29.1 µg/mL for HepG2 cells. Thus, the study illustrates that the preparation of nanocomposite generated through green synthesis with different methods significantly affects the structure and function and may improve the synthesis of nanocomposite to be developed into an efficacious therapeutic agent for cancers. In addition, this study opens the door toward a novel track in the field of nanocomposites as it links the synthesis with structure and function. Further anti-cancer properties, as well as animal testing are needed for those nanocomposites.

Ecofriendly biosynthesis of copper nanoparticles from novel marine S. rhizophila species for enhanced antibiofilm, antimicrobial and antioxidant potential

Marine microorganisms offer a promising avenue for the eco-friendly synthesis of nanoparticles due to their unique biochemical capabilities and adaptability to various environments. This study focuses on exploring the potential of a marine bacterial species, Stenotrophomonas rhizophila BGNAK1, for the synthesis of biocompatible copper nanoparticles and their application for hindering biofilms formed by monomicrobial species. The study begins with the isolation of the novel marine S. rhizophila species from marine soil samples collected from the West coast region of Kerala, India. The isolated strain is identified through 16S rRNA gene sequencing and confirmed to be S. rhizophila species. Biosynthesis of copper nanoparticles using S. rhizophila results in the formation of nanoparticles with size of range 10-50 nm. The nanoparticles exhibit a face-centered cubic crystal structure of copper, as confirmed by X-Ray Diffraction analysis. Furthermore, the synthesized nanoparticles display significant antimicrobial activity against various pathogenic bacteria and yeast. The highest inhibitory activity was against Staphylococcus aureus with a zone of 27 ± 1.00 mm and the least activity was against Pseudomonas aeruginosa with a zone of 22 ± 0.50 mm. The zone of inhibition against Candida albicans was 16 ± 0.60 mm. The antibiofilm activity against biofilm-forming clinical pathogens was evidenced by the antibiofilm assay and SEM images. Additionally, the copper nanoparticles exhibit antioxidant activity, as evidenced by their scavenging ability against DPPH, hydroxyl, nitric oxide, and superoxide radicals, as well as their reducing power in the FRAP assay. The study highlights the potential of the marine bacterium S. rhizophila BGNAK1 for the eco-friendly biosynthesis of copper nanoparticles with diverse applications. Synthesized nanoparticles exhibit promising antibiofilm, antimicrobial, and antioxidant properties, suggesting their potential utility in various fields such as medicine, wastewater treatment, and environmental remediation.

Escaping the ESKAPE pathogens: A review on antibiofilm potential of nanoparticles

ESKAPE pathogens, a notorious consortium comprising Enterococcusfaecium, Staphylococcusaureus, Klebsiellapneumoniae, Acinetobacterbaumannii, Pseudomonasaeruginosa, and Enterobacter species, pose formidable challenges in healthcare settings due to their multidrug-resistant nature. The increasing global cases of antimicrobial-resistant ESKAPE pathogens are closely related to their remarkable ability to form biofilms. Thus, understanding the unique mechanisms of antimicrobial resistance of ESKAPE pathogens and the innate resilience of biofilms against traditional antimicrobial agents is important for developing innovative strategies to establish effective control methods against them. This review offers a thorough analysis of biofilm dynamics, with a focus on the general mechanisms of biofilm formation, the significant contribution of persister cells in the resistance mechanisms, and the recurrence of biofilms in comparison to planktonic cells. Additionally, this review highlights the potential strategies of nanoparticles for managing biofilms in the ESKAPE group of pathogens. Nanoparticles, with their unique physicochemical properties, provide promising opportunities for disrupting biofilm structures and improving antimicrobial effectiveness. The review has explored interactions between nanoparticles and biofilms, covering a range of nanoparticle types such as metal, metal-oxide, surface-modified, and functionalized nanoparticles, along with organic nanoparticles and nanomaterials. The additional focus of this review also encompasses green synthesis techniques of nanoparticles that involve plant extract and supernatants from bacterial and fungal cultures as reducing agents. Furthermore, the use of nanocomposites and nano emulsions in biofilm management of ESKAPE is also discussed. To conclude, the review addresses the current obstacles and future outlooks in nanoparticle-based biofilm management, stressing the necessity for further research and development to fully exploit the potential of nanoparticles in addressing biofilm-related challenges.

A Comprehensive Review of Silver and Gold Nanoparticles as Effective Antibacterial Agents

The increasing threat from antibiotic-resistant bacteria has necessitated the development of novel methods to counter bacterial infections. In this context, the application of metallic nanoparticles (NPs), especially gold (Au) and silver (Ag), has emerged as a promising strategy due to their remarkable antibacterial properties. This review examines research published between 2006 and 2023, focusing on leading journals in nanotechnology, materials science, and biomedical research. The primary applications explored are the efficacy of Ag and Au NPs as antibacterial agents, their synthesis methods, morphological properties, and mechanisms of action. An extensive review of the literature on NPs synthesis, morphology, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and effectiveness against various Gram(+/-) bacteria confirms the antibacterial efficacy of Au and Ag NPs. The synthesis methods and characteristics of NPs, such as size, shape, and surface charge, are crucial in determining their antibacterial activity, as these factors influence their interactions with bacterial cells. Furthermore, this review underscores the urgent necessity of standardizing synthesis techniques, MICs, and reporting protocols to enhance the comparability and reproducibility of future studies. Standardization is essential for ensuring the reliability of research findings and accelerating the clinical application of NP-based antimicrobial approaches. This review aims to propel NP-based antimicrobial strategies by elucidating the properties that enhance the antibacterial activity of Ag and Au NPs. By highlighting their inhibitory effects against various bacterial strains and relatively low cytotoxicity, this work positions Ag and Au NPs as promising materials for developing antibacterial agents, making a significant contribution to global efforts to combat antibiotic-resistant pathogens.

Advancements in Green Nanoparticle Technology: Focusing on the Treatment of Clinical Phytopathogens

Opportunistic pathogenic microbial infections pose a significant danger to human health, which forces people to use riskier, more expensive, and less effective drugs compared to traditional treatments. These may be attributed to several factors, such as overusing antibiotics in medicine and lack of sanitization in hospital settings. In this context, researchers are looking for new options to combat this worrying condition and find a solution. Nanoparticles are currently being utilized in the pharmaceutical sector; however, there is a persistent worry regarding their potential danger to human health due to the usage of toxic chemicals, which makes the utilization of nanoparticles highly hazardous to eukaryotic cells. Multiple nanoparticle-based techniques are now being developed, offering essential understanding regarding the synthesis of components that play a crucial role in producing anti-microbial nanotherapeutic pharmaceuticals. In this regard, green nanoparticles are considered less hazardous than other forms, providing potential options for avoiding the extensive harm to the human microbiome that is prevalent with existing procedures. This review article aims to comprehensively assess the current state of knowledge on green nanoparticles related to antibiotic activity as well as their potential to assist antibiotics in treating opportunistic clinical phytopathogenic illnesses.

Multi-Hydrogen Bonding on Quaternized-Oligourea Receptor Facilitated Its Interaction with Bacterial Cell Membranes and DNA for Broad-Spectrum Bacteria Killing

Herein, we report a new strategy for the design of antibiotic agents based on the electrostatic interaction and hydrogen bonding, highlighting the significance of hydrogen bonding and the increased recognition sites in facilitating the interaction with bacterial cell membranes and DNA. A series of quaternary ammonium functionalized urea-based anion receptors were studied. While the monodentate mono-urea M1, bisurea M2, and trisurea M3 failed to break through the cell membrane barrier and thus could not kill bacteria, the extended bidentate dimers D1-D3 presented gradually increased membrane penetrating capabilities, DNA conformation perturbation abilities, and broad-spectrum antibacterial activities against E. coli, P. aeruginosa, S. aureus, E. faecalis, and S. epidermidis.

Antibiotic resistance and nanotechnology: A narrative review

The rise of antibiotic resistance poses a significant threat to public health worldwide, leading researchers to explore novel solutions to combat this growing problem. Nanotechnology, which involves manipulating materials at the nanoscale, has emerged as a promising avenue for developing novel strategies to combat antibiotic resistance. This cutting-edge technology has gained momentum in the medical field by offering a new approach to combating infectious diseases. Nanomaterial-based therapies hold significant potential in treating difficult bacterial infections by circumventing established drug resistance mechanisms. Moreover, their small size and unique physical properties enable them to effectively target biofilms, which are commonly linked to resistance development. By leveraging these advantages, nanomaterials present a viable solution to enhance the effectiveness of existing antibiotics or even create entirely new antibacterial mechanisms. This review article explores the current landscape of antibiotic resistance and underscores the pivotal role that nanotechnology plays in augmenting the efficacy of traditional antibiotics. Furthermore, it addresses the challenges and opportunities within the realm of nanotechnology for combating antibiotic resistance, while also outlining future research directions in this critical area. Overall, this comprehensive review articulates the potential of nanotechnology in addressing the urgent public health concern of antibiotic resistance, highlighting its transformative capabilities in healthcare.

Synthesis of biopolymer blends nanocomposites embedded with mono-(Ag, Fe) and bi-(Ag-Fe) metallic nanoparticles using an eco-friendly approach for antimicrobial activities

Plant-mediated solution casting is used to develop eco-friendly polymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) doped with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were studied to understand their electromagnetic interface (EMI) shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties. The Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) characterization techniques were used to examine the interactions between the polymers, the presence of silver and ferrous particles in the composites, the crystallinity shift, the surface morphology, the shape and size of the nanoparticles and the distribution of the nanoparticles in the composites. The FTIR spectra showed the interactions among the components of the composites. According to XRD spectra, the incorporation of nanoparticles into the PVA polymer significantly reduced the crystalline character of the polymer from 0.38 to 0.24 for the composition consisting of silver and iron nanoparticles in equal proportion. The results from SEM, EDX and XRD corroborate the presence of nanoparticle forms. The thermogravimetric analysis (TGA) tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites. The tensile properties showed that the addition of nanoparticles to the PVA/PVP polymer matrix increased its mechanical strength from 59.3 MPa to 85.5 MPa. We examined its efficacy against Escherichia coli, Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown enhanced, loss due to reflection, loss due to absorption, and the total EMI shielding efficiency at 8 GHz (X-band) and 16 GHz (Ku-band) frequency. All these results ratify, that these newly developed bio nanocomposites are most suitable in many applications, in EMI shielding, nanotechnology, and medical fields.

Quorum Quenching Approaches against Bacterial-Biofilm-Induced Antibiotic Resistance

With the widespread phenomenon of antibiotic resistance and the diffusion of multiple drug-resistant bacterial strains, enormous efforts are being conducted to identify suitable alternative agents against pathogenic microorganisms. Since an association between biofilm formation and antibiotic resistance phenotype has been observed, a promising strategy pursued in recent years focuses on controlling and preventing this formation by targeting and inhibiting the Quorum Sensing (QS) system, whose central role in biofilm has been extensively demonstrated. Therefore, the research and development of Quorum Quenching (QQ) compounds, which inhibit QS, has gradually attracted the attention of researchers and has become a new strategy for controlling harmful microorganisms. Among these, a number of both natural and synthetic compounds have been progressively identified as able to interrupt the intercellular communication within a microbial community and the adhesion to a surface, thus disintegrating mature/preformed biofilms. This review describes the role played by QS in the formation of bacterial biofilms and then focuses on the mechanisms of different natural and synthetic QS inhibitors (QSIs) exhibiting promising antibiofilm ability against Gram-positive and Gram-negative bacterial pathogens and on their applications as biocontrol strategies in various fields.

Nanoparticles of Cs0.33WO3 as Antibiofilm Agents and Photothermal Treatment to Inhibit Biofilm Formation

Metal oxide nanoparticles with photothermal properties have attracted considerable research attention for their use in biomedical applications. Cesium tungsten oxide (Cs0.33WO3) nanoparticles (NPs) exhibit strong absorption in the NIR region due to localized surface plasmon resonance, through which they convert light to heat; hence, they can be applied to photothermal treatment for bacteria and biofilm ablation. Herein, Cs0.33WO3 NPs were synthesized through solid-phase synthesis, and their physical properties were characterized through Zetasizer, energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer, and scanning and transmission electron microscopy (SEM and TEM, respectively). Burkholderia cenocepacia isolates were cultured in tryptic soy broth supplemented with glucose, and the biofilm inhibition and antibiofilm effects of the NPs were determined using a crystal violet assay and the Cell Counting Kit-8 (CCK-8) assay. The biofilm morphology and viability of NP-treated cultures after NIR irradiation were evaluated through SEM and confocal microscopy, respectively. The cytotoxicity of NPs to human macrophages was also assessed using the CCK-8 assay. The NPs effectively inhibited biofilm formation, with a formation rate of <10% and a viability rate of <50% at the concentration of ≥200 μg/mL. The confocal analysis revealed that NIR irradiation markedly enhanced biofilm cytotoxicity after treatment with the NPs. The assay of cytotoxicity to human macrophages demonstrated the biocompatibility of the NPs and NIR irradiation. In sum, the Cs0.33WO3 NPs displayed effective biofilm inhibition and antibiofilm activity at 200 μg/mL treatment concentration; they exhibited an enhancement effect under the NIR irradiation, suggesting Cs0.33WO3 NPs are a potential candidate agent for NIR-irradiated photothermal treatment in bacterial biofilm inhibition and antibiofilm.

Possible Molecular Targeting of Biofilm-Associated Genes by Nano-Ag in Candida albicans

The treatment of candidiasis infections is hindered by the presence of biofilms. Here, we report the biofilm-associated genes as potential molecular targets by silver nanoparticles (nano-Ag) in Candida albicans. Nano-Ag was biosynthesized using Bacillus licheniformis, Bacillus cereus, and Fusarium oxysporum. The physicochemical properties of the microbial-synthesized of nano-Ag are widely characterized by visual observation, ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. Characterization results revealed the formation of nano-Ag. Antiplanktonic cells and antibiofilm activities of nano-Ag were also demonstrated by minimum inhibition concentrations (MIC), minimum fungicidal concentration (MFC), MFC/MIC ratio, crystal violet staining, 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT), and microscopic image analysis. We have analyzed the expressions of biofilm-associated genes in C. albicans treated with different concentrations of nano-Ag based on MIC. The expression profile of BCR1, ALS1, ALS3, HWP1, and ECE1 showed downregulated genes involved in these pathways by the treatment with nanoparticles. Negative regulators, TUP1, NRG1, and TOR1, were upregulated by the treatment of nano-Ag. Our study suggests that nano-Ag affects gene expression and may subsequently decrease the pathogenesis of C. albicans by inhibiting biofilm formation. Molecular targeting of biofilm-associated genes involved in biofilm formation by nano-Ag may be an effective treatment strategy for candidiasis infections.

Silk Sericin and Its Composite Materials with Antibacterial Properties to Enhance Wound Healing: A Review

Wound infections may disrupt the normal wound-healing process. Large amounts of antibiotics are frequently used to prevent pathogenic infections; however, this can lead to resistance development. Biomaterials possessing antimicrobial properties have promising applications for reducing antibiotic usage and promoting wound healing. Silk sericin (SS) has been increasingly explored for skin wound healing applications owing to its excellent biocompatibility and antioxidant, antimicrobial, and ultraviolet-resistant properties. In recent years, SS-based composite biomaterials with a broader antimicrobial spectrum have been extensively investigated and demonstrated favorable efficacy in promoting wound healing. This review summarizes various antimicrobial agents, including metal nanoparticles, natural extracts, and antibiotics, that have been incorporated into SS composites for wound healing and elucidates their mechanisms of action. It has been revealed that SS-based biomaterials can achieve sustained antimicrobial activity by slow-release-loaded antimicrobial agents. The antimicrobial-loaded SS composites may promote wound healing through anti-infection, anti-inflammation, hemostasis, angiogenesis, and collagen deposition. The manufacturing methods, benefits, and limitations of antimicrobial-loaded SS materials are briefly discussed. This review aims to enhance the understanding of new advances and directions in SS-based antimicrobial composites and guide future biomedical research.

Use of nanotechnology-based nanomaterial as a substitute for antibiotics in monogastric animals

Nanotechnology has emerged as a promising solution for tackling antibiotic resistance in monogastric animals, providing innovative methods to enhance animal health and well-being. This review explores the novel use of nanotechnology-based nanomaterials as substitutes for antibiotics in monogastric animals. With growing global concerns about antibiotic resistance and the need for sustainable practices in animal husbandry, nanotechnology offers a compelling avenue to address these challenges. The objectives of this review are to find out the potential of nanomaterials in improving animal health while reducing reliance on conventional antibiotics. We examine various forms of nanomaterials and their roles in promoting gut health and also emphasize fresh perspectives brought by integrating nanotechnology into animal healthcare. Additionally, we delve into the mechanisms underlying the antibacterial properties of nanomaterials and their effectiveness in combating microbial resistance. By shedding light on the transformative role of nanotechnology in animal production systems. This review contributes to our understanding of how nanotechnology can provide safer and more sustainable alternatives to antibiotics.

Synergistic activity of gold nanoparticles with amphotericin B on persister cells of Candida tropicalis biofilms

AIM

The antifungal activity was studied on sessile and persister cells (PCs) of Candida tropicalis biofilms of gold nanoparticles (AuNPs) stabilized with cetyltrimethylammonium bromide (CTAB-AuNPs) and those conjugated with cysteine, in combination with Amphotericin B (AmB).

MATERIALS/METHODS

The PC model was used and synergistic activity was tested by the checkerboard assay. Biofilms were studied by crystal violet and scanning electron microscopy.

RESULTS/CONCLUSIONS

After the combination of both AuNPs and AmB the biofilm biomass was reduced, with significant differences in architecture being observed with a reduced biofilm matrix. In addition, the CTAB-AuNPs-AmB combination significantly reduced PCs. Understanding how these AuNPs aid in the fight against biofilms and the development of new approaches to eradicate PCs has relevance for chronic infection treatment.

Antibacterial efficacy, mode of action, and safety of a novel nano-antibiotic against antibiotic-resistant Escherichia coli strains

Globally rising antibiotic-resistant (AR) and multi-drug resistant (MDR) bacterial infections are of public health concern due to treatment failure with current antibiotics. Enterobacteria, particularly Escherichia coli, cause infections of surgical wound, bloodstream, and urinary tract, including pneumonia and sepsis. Herein, we tested in vitro antibacterial efficacy, mode of action (MoA), and safety of novel amino-functionalized silver nanoparticles (NH2-AgNP) against the AR bacteria. Two AR E. coli strains (i.e., ampicillin- and kanamycin-resistant E. coli), including a susceptible strain of E. coli DH5α, were tested for susceptibility to NH2-AgNP using Kirby-Bauer disk diffusion and standard growth assays. Dynamic light scattering (DLS) was used to determine cell debris and relative conductance was used as a measure of cell leakage, and results were confirmed with transmission electron microscopy (TEM). Multiple oxidative stress assays were used for in vitro safety evaluation of NH2-AgNP in human lung epithelial cells. Results showed that ampicillin and kanamycin did not inhibit growth in either AR bacterial strain with doses up to 160 μg/mL tested. NH2-AgNP exhibited broad-spectrum bactericidal activity, inhibiting the growth of all three bacterial strains at doses ≥1 μg/mL. DLS and TEM revealed cell debris formation and cell leakage upon NH2-AgNP treatment, suggesting two possible MoAs: electrostatic interactions followed by cell wall damage. Safety evaluation revealed NH2-AgNP as noncytotoxic and antioxidative to human lung epithelial cells. Taken together, these results suggest that NH2-AgNP may serve as an effective and safer bactericidal therapy against AR bacterial infections compared to common antibiotics.

Effect of Topical Silver Nanoparticle Formulation on Wound Bacteria Clearance and Healing in Patients With Infected Wounds Compared to Standard Topical Antibiotic Application: A Randomized Open-Label Parallel Clinical Trial

BACKGROUND

Infected wounds pose a special challenge for management, with an increased risk of wound chronicity, systemic infection, and the emergence of antibiotic resistance. Silver nanoparticles have multimodal effects on bacteria clearance and wound healing. This study aimed to document the efficacy of a topical silver nanoparticle-based cream on bacteria clearance and wound healing in infected wounds compared to Mupirocin.

METHODS

This open-label parallel randomized clinical trial allocated 86 participants with infected wounds (culture-positive) into Kadermin, silver nanoparticle-based cream arm (n=43) and Mupirocin arm (n=43) and documented the swab culture on day 5 and wound healing at day 28, along with periodic wound status using the Bates-Jensen Wound Assessment Tool. Patients received oral/systemic antibiotics and other medications for underlying diseases. The intention-to-treat principle was adopted for data analysis using the chi-square and Student t tests to document the differences between groups according to variable characteristics.

RESULTS

All participants completed the follow-up. On day 5, wound bacteria clearance was observed in 86% and 65.1% of the participants in the Kadermin and Mupirocin arms, respectively (p=0.023). At day 28, complete wound healing was observed in 81.4% and 37.2% of the participants in the Kadermin and Mupirocin arms, respectively (p≤0.001). No local or systemic adverse event or local reaction was observed in any of the participants.

CONCLUSION

Kadermin, the silver nanoparticle-based cream, has better efficacy in achieving faster wound bacteria clearance and healing in infected wounds compared to Mupirocin. This may have relevance for its use as an antibiotic-sparing agent in wound management.

Biogenic Synthesis of Selenium and Copper Oxide Nanoparticles and Inhibitory Effect against Multi-Drug Resistant Biofilm-Forming Bacterial Pathogens

Antimicrobial resistance (AMR), caused by microbial infections, has become a major contributor to morbid rates of mortality worldwide and a serious threat to public health. The exponential increase in resistant pathogen strains including Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) poses significant hurdles in the health sector due to their greater resistance to traditional treatments and medicines. Efforts to tackle infectious diseases caused by resistant microbes have prompted the development of novel antibacterial agents. Herein, we present selenium and copper oxide monometallic nanoparticles (Se-MMNPs and CuO-MMNPs), characterized using various techniques and evaluated for their antibacterial potential via disc diffusion, determination of minimum inhibitory concentration (MIC), antibiofilm, and killing kinetic action. Dynamic light scattering (DLS), scanning electron microscopy (SEM/EDX), and X-ray diffraction (XRD) techniques confirmed the size-distribution, spherical-shape, stability, elemental composition, and structural aspects of the synthesized nanoparticles. The MIC values of Se-MMNPs and CuO-MMNPs against S. aureus and E. coli were determined to be 125 μg/mL and 100 μg/mL, respectively. Time-kill kinetics studies revealed that CuO-MMNPs efficiently mitigate the growth of S. aureus and E. coli within 3 and 3.5 h while Se-MMNPs took 4 and 5 h, respectively. Moreover, CuO-MMNPs demonstrated better inhibition compared to Se-MMNPs. Overall, the proposed materials exhibited promising antibacterial activity against S. aureus and E. coli pathogens.

A review on mycogenic metallic nanoparticles and their potential role as antioxidant, antibiofilm and quorum quenching agents

The emergence of antimicrobial resistance among biofilm forming pathogens aimed to search for the efficient and novel alternative strategies. Metallic nanoparticles have drawn a considerable attention because of their significant applications in various fields. Numerous methods are developed for the generation of these nanoparticles however, mycogenic (fungal-mediated) synthesis is attractive due to high yields, easier handling, eco-friendly and being energy efficient when compared with conventional physico-chemical methods. Moreover, mycogenic synthesis provides fungal derived biomolecules that coat the nanoparticles thus improving their stability. The process of mycogenic synthesis can be extracellular or intracellular depending on the fungal genera used and various factors such as temperature, pH, biomass concentration and cultivation time may influence the synthesis process. This review focuses on the synthesis of metallic nanoparticles by using fungal mycelium, mechanism of synthesis, factors affecting the mycosynthesis and also describes their potential applications as antioxidants and antibiofilm agents. Moreover, the utilization of mycogenic nanoparticles as quorum quenching agent in hampering the bacterial cell-cell communication (quorum sensing) has also been discussed.

Unleashing the promise of emerging nanomaterials as a sustainable platform to mitigate antimicrobial resistance

The emergence and spread of antibiotic-resistant (AR) bacterial strains and biofilm-associated diseases have heightened concerns about exploring alternative bactericidal methods. The WHO estimates that at least 700 000 deaths yearly are attributable to antimicrobial resistance, and that number could increase to 10 million annual deaths by 2050 if appropriate measures are not taken. Therefore, the increasing threat of AR bacteria and biofilm-related infections has created an urgent demand for scientific research to identify novel antimicrobial therapies. Nanomaterials (NMs) have emerged as a promising alternative due to their unique physicochemical properties, and ongoing research holds great promise for developing effective NMs-based treatments for bacterial and viral infections. This review aims to provide an in-depth analysis of NMs based mechanisms combat bacterial infections, particularly those caused by acquired antibiotic resistance. Furthermore, this review examines NMs design features and attributes that can be optimized to enhance their efficacy as antimicrobial agents. In addition, plant-based NMs have emerged as promising alternatives to traditional antibiotics for treating multidrug-resistant bacterial infections due to their reduced toxicity compared to other NMs. The potential of plant mediated NMs for preventing AR is also discussed. Overall, this review emphasizes the importance of understanding the properties and mechanisms of NMs for the development of effective strategies against antibiotic-resistant bacteria.

Therapeutic bacteria and viruses to combat cancer: double-edged sword in cancer therapy: new insights for future

Cancer, ranked as the second leading cause of mortality worldwide, leads to the death of approximately seven million people annually, establishing itself as one of the most significant health challenges globally. The discovery and identification of new anti-cancer drugs that kill or inactivate cancer cells without harming normal and healthy cells and reduce adverse effects on the immune system is a potential challenge in medicine and a fundamental goal in Many studies. Therapeutic bacteria and viruses have become a dual-faceted instrument in cancer therapy. They provide a promising avenue for cancer treatment, but at the same time, they also create significant obstacles and complications that contribute to cancer growth and development. This review article explores the role of bacteria and viruses in cancer treatment, examining their potential benefits and drawbacks. By amalgamating established knowledge and perspectives, this review offers an in-depth examination of the present research landscape within this domain and identifies avenues for future investigation.

Zinc Oxide-Based Nanomaterials for Microbiostatic Activities: A Review

The world is fighting infectious diseases. Therefore, effective antimicrobials are required to prevent the spread of microbes and protect human health. Zinc oxide (ZnO) nano-materials are known for their antimicrobial activities. Because of their distinctive physical and chemical characteristics, they can be used in medical and environmental applications. ZnO-based composites are among the leading sources of antimicrobial research. They are effective at killing (microbicidal) and inhibiting the growth (microbiostatic) of numerous microorganisms, such as bacteria, viruses, and fungi. Although most studies have focused on the microbicidal features, there is a lack of reviews on their microbiostatic effects. This review provides a detailed overview of available reports on the microbiostatic activities of ZnO-based nano-materials against different microorganisms. Additionally, the factors that affect the efficacy of these materials, their time course, and a comparison of the available antimicrobials are highlighted in this review. The basic properties of ZnO, challenges of working with microorganisms, and working mechanisms of microbiostatic activities are also examined. This review underscores the importance of further research to better understand ZnO-based nano-materials for controlling microbial growth.

LSPR sensing for in situ monitoring the Ag dissolution of Au@Ag core-shell nanoparticles in biological environments

Silver nanoparticles (AgNPs) are extensively used as an antibacterial agent, and monitoring the dissolution behavior of AgNPs in native biological environments is critical in both optimizing their performance and regulating their safety. However, current assessment methods rely on sophisticated analytical tools that are off-site and time-consuming with potential underestimations, due to complicated sample preparation. Although localized surface plasmon resonance (LSPR) sensing offers a facile method for the detection of AgNP dissolution, it is limited by low sensitivity and poor nanoparticle stability in native biological environments. Herein, we constructed a highly sensitive and stable LSPR sensor using gold-silver core-shell nanoparticles (Au@AgNPs), in combination with polymeric stabilizing agents, for the direct measurement of the Ag shell dissolution in native biological media. The high sensitivity was attributed to the acute and large LSPR shift generated by bimetallic nanoparticles. The sensor was used for the real-time monitoring of the Ag dissolution of Au@AgNPs during their co-culture with both bacteria and fibroblast cells. The media pH was found to dominate the Ag dissolution process, where Au@AgNPs exhibited bactericidal effects in the bacteria environment with relatively low pH, but they showed little toxicity towards fibroblast cells at pH 7.4. The minimum inhibition concentration of Au@AgNPs for bacterial growth was found similar to that of AgNO3 in terms of released Ag amount. Thus, stabilized Au@AgNPs not only allow the in-situ monitoring of Ag dissolution via LSPR sensing but also constitute an effective antibacterial agent with controlled toxicity, holding great potential for future biomedical and healthcare applications.