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The high volatility and hydrophobicity of cinnamon essential oils (CiEO) limited their practical application. To enhance their stability and antibacterial activity, nanoemulsions encapsulating CiEO were prepared using hydroxypropyl-β-cyclodextrin/lauroyl arginate (HPCD/LAE) inclusion complexes through high-pressure microfluidization (HPM). Effects of HPM parameters on the stability and antibacterial properties of nanoemulsion were investigated. Results revealed that increased processing pressure and cycle numbers were associated with reduced droplet size and greater homogeneity in CiEO distribution. Storage and thermal stability were optimized at 100 MPa and seven cycles. Moreover, the nanoemulsions showed strong synergistic antibacterial against E. coli (19.79 mm) and S. aureus (23.61 mm) compared with LAE (11.52 mm and 12.82 mm, respectively) and CiEO alone (13.26 mm and 17.68 mm, respectively). This study provided new information for constructing CiEO nanoemulsion, which is suitable for use in the food industry., Competing Interests: Declaration of competing interest The authors have no competing financial or personal interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The aim of the present study is to synthesize Cu 1-x Sr x S (x = 0.00, 0.025, 0.05, 0.075, and 0.1) nanoparticles (NPs) using an easy chemical co-precipitation method in an efficient, inexpensive, and simple technique. The structural, morphological, and optical properties of the prepared samples were investigated using XRD, TEM, XRF, UV-Vis DRS, and PL characterization techniques. XRD spectra confirmed the Sr-doped copper sulfide nanoparticles have a hexagonal structure with crystallite sizes ranging from 15.15 to 16.04 nm, and, by XRF, the presence of the dopant was detected. TEM analysis confirmed that strontium ions had an effect on the shape of the CuS nanostructure, and the particle size increased from 16.27 to 17.32 nm after doping. A study using UV-Vis showed the presence of Sr doping increased the optical energy band gap (1.38 eV to 1.59 eV). At room temperature, one photoluminescence (PL) band was found at 826 nm. The antibacterial activity of CuS nanostructures against E. coli, P. aeruginosa, Klebsiella pneumonia, and S. aureus was evaluated by zone of inhibition. Sr doped CuS NPs exhibited the highest antibacterial activity against S. aureus (17 to 29 mm). Also, the results demonstrated that samples doped with 5, 7.5, and 10% Sr exhibited inhibitory effects against all the tested microbial strains higher than the antibiotic., (© 2024. The Author(s).)

The cationic peptide octaarginine (R8) is a prominent cell-penetrating peptide and has been extensively researched as a carrier of diverse cell-destined cargo. In this work, we describe the coassembly of R8 with small molecule thiazolyl benzenesulfonamide (TBS) derivatives. Physical complexation of R8 with three TBS derivatives across a range of weight ratios results in the formation of a distinctive set of nano- and microstructures. A detailed structural characterization of the R8:TBS-derivative coassemblies has been performed by a combination of FTIR, XRD, SEM, and DSC. The major functional groups that facilitate coassembly include sulfonamide SO 2 and NH groups of the TBS derivatives, and the guanidinium of R8, via a combination of cation-π and hydrogen-bonding interactions. The R8:4F-TBS coassembly displays singular topological features compared to R8:4Br-TBS and R8:4CH 3 -TBS complexes. These differences are attributed to the changes in the preferred orientation of the guanidino groups of R8 with respect to the π-surface of TBS derivatives. The modulation of forces of interaction across the R8:TBS-derivative coassemblies aligns with their respective thermal stabilities. The single-crystal structure of bare 4F-TBS has been subjected to Hirshfeld and 2D fingerprinting analysis and indicates notable variations from the crystal packing of the R8:4F-TBS coassembly. The structural differences among the R8:TBS-derivative coassemblies correlate with distinctive profiles of antibacterial activity in each case. The coassembled structures exert a variable extent of bacterial membrane disruption and damage based on the unique disposition of R8 and the potency of small molecule in each case. The aqueous suspension of R8:4F-TBS displays significant outer membrane disruption and bacterial killing compared with the other complexes. This work successfully demonstrates the hitherto unreported potential for coassembly of cell-penetrating peptides with other entities. The coassembly of R8 with small molecules highlights an attractive strategy for tuning the functional properties of each component.

Contact-dependent inhibition (CDI) is a mechanism of interbacterial competition in Gram-negative bacteria. Bacteria that contain CDI systems produce a large, filamentous protein, CdiA, on their cell surfaces. CdiA contains a C-terminal toxin domain that is transported across the outer membranes (OMs) of neighboring bacteria. Once inside a target bacterium, the toxin is released from the CdiA protein via a proteolytic mechanism that has not been well characterized. We have developed an in vitro assay to monitor this toxin release process and have identified several conserved amino acids that play critical roles in the autocatalytic mechanism. Our results indicate that a hydrophobic, membrane-like environment is required for CdiA to fold, and the proteolysis occurs through an asparagine cyclization mechanism. Our in vitro assay thus provides a starting point for analyzing the conformational state of the CdiA protein when it is inserted into a target cell's OM and engaged in transporting the toxin across that membrane., Importance: It is challenging to develop new antibiotics capable of killing Gram-negative bacteria because their outer membranes are impermeable to many small molecules. Some Gram-negative bacteria, however, deliver much larger protein toxins through the outer membranes of competing bacteria in their environments using contact-dependent inhibition (CDI) systems. How these toxins traverse the outer membranes of their targets is not well understood. We have therefore developed a method to study the toxin delivery process in a highly simplified system using a fragment of a CDI protein. Our results indicate that the CDI protein assembles into a structure in the target membrane that catalyzes the release of the toxin. This CDI protein fragment enables further studies of the toxin delivery mechanism., Competing Interests: The authors declare no conflict of interest.

Small multidrug resistance (SMR) transporters are key players in the defense of multidrug-resistant pathogens to toxins and other homeostasis-perturbing compounds. However, recent evidence demonstrates that EmrE, an SMR from Escherichia coli and a model for understanding transport, can also induce susceptibility to some compounds by drug-gated proton leak. This runs down the ∆pH component of the proton-motive force (PMF), reducing the viability of the affected bacteria. Proton leak may provide an unexplored drug target distinct from the targets of most known antibiotics. Activating proton leak requires an SMR to be merely present, rather than be the primary resistance mechanism, and dissipates the energy source for many other efflux pumps. PAsmr, an EmrE homolog from Pseudomonas aeruginosa , transports many EmrE substrates in cells and purified systems. We hypothesized that PAsmr, like EmrE, may confer susceptibility to some compounds via drug-gated proton leak. Growth assays of E. coli expressing PAsmr displayed substrate-dependent resistance and susceptibility phenotypes, and in vitro solid-supported membrane electrophysiology experiments revealed that PAsmr performs both antiport and substrate-gated proton uniport, demonstrating the same functional promiscuity observed in EmrE. Growth assays of P. aeruginosa strain PA14 demonstrated that PAsmr contributes resistance to some antimicrobial compounds, but no growth defect is observed with susceptibility substrates, suggesting P. aeruginosa can compensate for the proton leak occurring through PAsmr. These phenotypic differences between P. aeruginosa and E. coli advance our understanding of the underlying resistance mechanisms in P. aeruginosa and prompt further investigation into the role that SMRs play in antibiotic resistance in pathogens., Importance: Small multidrug resistance (SMR) transporters are a class of efflux pumps found in many pathogens, although their contributions to antibiotic resistance are not fully understood. We hypothesize that these transporters may confer not only resistance but also susceptibility, by dissipating the proton-motive force. This means to use an SMR transporter as a target; it merely needs to be present (as opposed to being the primary resistance mechanism). Here, we test this hypothesis with an SMR transporter found in Pseudomonas aeruginosa and find that it can perform both antiport (conferring resistance) and substrate-gated proton leak. Proton leak is detrimental to growth in Escherichia coli but not P. aeruginosa , suggesting that P. aeruginosa responds differently to or can altogether prevent ∆pH dissipation., Competing Interests: The authors declare no conflict of interest.

Inosine 5'-monophosphate dehydrogenase (IMPDH), known as GuaB in bacteria, catalyzes the rate-limiting step in de novo guanine biosynthesis and is conserved from humans to bacteria. We developed a series of potent inhibitors that selectively target GuaB over its human homolog. Here, we show that these GuaB inhibitors are bactericidal, generate phenotypic signatures that are distinct from other antibiotics, and elicit different time-kill kinetics and regulatory responses in two important Gram-negative pathogens: Acinetobacter baumannii and Escherichia coli . Specifically, the GuaB inhibitor G6 rapidly kills A. baumannii but only kills E. coli after 24 h. After exposure to G6, the expression of genes involved in purine biosynthesis and stress responses change in opposite directions while siderophore biosynthesis is downregulated in both species. Our results suggest that different species respond to GuaB inhibition using distinct regulatory programs and possibly explain the different bactericidal kinetics upon GuaB inhibition. The comparison highlights opportunities for developing GuaB inhibitors as novel antibiotics.IMPORTANCE A. baumannii is a priority bacterial pathogen for which development of new antibiotics is urgently needed due to the emergence of multidrug resistance. We recently developed a series of specific inhibitors against GuaB, a bacterial inosine 5'-monophosphate dehydrogenase, and achieved sub-micromolar minimum inhibitory concentrations against A. baumannii . GuaB catalyzes the rate-limiting step of de novo guanine biosynthesis and is highly conserved across bacterial pathogens. This study shows that inhibition of GuaB induced a bacterial morphological profile distinct from that of other classes of antibiotics, highlighting a novel mechanism of action. Moreover, our transcriptomic analysis showed that regulation of de novo purine biosynthesis and stress responses of A. baumannii upon GuaB inhibition differed significantly from that of E. coli ., Competing Interests: The authors declare no conflict of interest.

Using plant extracts in the green synthesis of nanoparticles has become an environmentally acceptable approach. In our study, copper oxide nanoparticles (CuO NPs) were synthesized using ethanolic extracts of Azadirachta indica and Simmondsia chinensis. CuO NP formation was confirmed by the change in color and by UV‒visible spectroscopy (CuO NPs peaked at a wavelength of 344 nm). TEM images confirmed the semispherical shape of the CuO NPs, with particle sizes ranging from 30.9 to 10.7 nm. The antibacterial activity of these NPs was evaluated by using the agar diffusion method against clinical isolates, including methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Pseudomonas aeruginosa, Acinetobacter spp., Klebsiella pneumoniae, and Stenotrophomonas maltophilia. The minimum inhibitory concentration (MIC) of CuO NPs ranged from 62.5 to 125 µg/ml. In contrast, the antioxidant activity and antibiofilm activity of CuO NPs ranged from 31.1 to 92.2% at 125-500 µg/ml and 62.2-95%, respectively, at 125 -62.5 µg/ml. Our results confirmed that CuO NPs had IC50s of 383.41 ± 3.4 and 402.73 ± 1.86 at 250 µg/mL against the HBF4 cell line. Molecular docking studies with CuO NPs suggested that penicillin-binding protein 4 (PBP4) and beta-lactamase proteins (OXA-48) strongly bind to S. aureus and K. pneumoniae, respectively, with CuO NPs. Our study confirms the promising use of CuO NPs in treating pathogenic bacteria and that CuO NPs could be possible alternative antibiotics. This study supports the pharmaceutical and healthcare sectors in Egypt and worldwide., (© 2024. The Author(s).)

Concentration control of some drug are used commonly however their uncontrolled concentration renders severe side effects. Therefore, it is substantial to come up with innovation release control methods. There is a strong affinity between the phospholipid of nanoliposomes and wool cells which facilitate the diffusion of liposomes into the wool structure. On the other hand, polyhexamethylene biguanide (PHMB) has gained popularity as an antibacterial agent; however, the compound's cytotoxicity has limited its usefulness. By compounding these facts, this work introduces a novel method for sustained drug release via internalization. In this method, PHMB was detained into nanoliposomes infiltrated the wool to generate an extremely regulated release, which was established using various techniques. SEM pictures demonstrated effective absorption of nanoliposome-encapsulated PHMB within the wool fabric. The developed wound dressing showed a sustained drug release, and consequently, perfect biocompatibility and enduring antibacterial activity., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Disposal of the cow dung pollutants arising from cattle farming threatens the environment and public safety in diverse ways. To date, researchers have worked on developing new pathways to control and manage cattle farming wastes, but most do not involve the reuse of these wastes. Herein, a cow dung biochar-modulated photothermal N -halamine hydrogel (i.e., PAN/CA/CoBC/pMAG-Cl) was designed for converting cow dung into biochar (CoBC), which was then coupled with a 3D interpenetrating hydrogel network to treat infected wounds. The PAN/CA/CoBC/pMAG-Cl hydrogel exhibited excellent synergistic antibacterial performance against 10 6 CFU·mL -1 Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) within 60 min. The bactericidal effect was multimodal, involving CoBC-based photothermal killing (i.e., temperature as high as 80.5 °C) after 808 nm near-infrared light irradiation for 10 min, contact killing through the strong oxidative characteristic of N -halamine (pMAG-Cl), and release killing via active halogens (i.e., Cl + ) reinforced by the photothermal action of CoBC. The S. aureus -infected wound model in vivo demonstrated that the PAN/CA/CoBC/pMAG-Cl hydrogel worked as an ideal wound dressing, capable of resisting bacterial infection, accelerating the healing process, and promoting epithelial regeneration. This proposed strategy could indicate a new way for the disposal of cow dung pollutant and its reuse in antibacterial-associated applications.

Given the variability in wounds based on the underlying causes, personalized medicine and tailored care for patients with wounds are required to ensure optimal therapeutic outcomes. With the emergence of high-precision and high-efficiency photocuring 3D printing technology, there is the potential for its use in customizing precise shapes that can match complex wound sites, thereby providing better treatment for patients with wound infections. In this work, porphyrinic metal-organic framework (MOF) crystals, serving as the functional filler, were incorporated into gelatin methacrylate (GelMA) as a photocurable composite resin to investigate the capabilities of producing customizable wound dressings through vat photopolymerization 3D printing. The embedded MOF crystals allow for better control of the photopolymerization process due to photon competition with the photoinitiator, enabling the precise printing of complex structures. In addition, these crystals impart photothermal and photodynamic capabilities to the printed object. The antibacterial assay confirms the potent photothermal and photodynamic bactericidal properties of the printed GelMA/MOF hydrogels. The hydrogel with the highest MOF content exhibited over 99.99% antibacterial efficiency against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli after 30 min of light exposure (∼30 mW/cm 2 , λ ≥ 420 nm). Simultaneously, hemolysis and cytotoxicity evaluations validated their excellent biocompatibility. The findings presented here introduce a strategy for integrating photosensitive MOF and 3D printing to fabricate size-adjustable photothermal/photodynamic monoliths and patches, opening perspectives toward personalized treatment for wound management.

The quality deterioration of postharvest fruits is greatly influenced by ethylene, leading to food wastage worldwide. Therefore, it is urgent to develop an efficient packaging strategy to reduce ethylene concentration and prolong the shelf life of perishable fruits. In this work, a surface-molding hydrogel film was created using ZIF-8 in combination with carboxymethyl starch (CMS) and carboxymethyl chitosan (CMCS). Specifically, ZIF-8 is first anchored on CMS and then rapidly cross-linked in situ with CMCS, forming ZIF-8@CC on the fruit surface (within 10 s). The perfect tight-fitting effects of ZIF-8@CC were observed on various fruit surfaces with different roughness (Ra: ranges from 102 to 308 nm). ZIF-8@CC could absorb 57.3% endogenous ethylene from bananas, and the interaction mechanism between ethylene and ZIF-8 was studied by molecular dynamics simulations, providing insights into the ethylene adsorption capacity of ZIF-8@CC. Moreover, ZIF-8@CC presented excellent antibacterial properties and achieved satisfactory ultralong preservation effects on both nonclimatic and climatic fruits (12 days for strawberries and 14 days for bananas) at room temperature. Importantly, ZIF-8@CC is easily removed, washed, and degradable. These findings offer an efficient and potential food packing material with multifunctional properties for preserving perishable fruits.

Thermoplastic polyurethanes (TPUs) are one of the most appealing materials with extensive applications in biomedical fields due to their versatile mechanical properties and excellent biocompatibility. In response to the escalating challenges of bacterial infections, it is desirable to obtain TPUs with intrinsic antibacterial activity, particularly for application in biomedical devices and public places. Herein, a cationic main-/side-chain structure regulation strategy in the TPU hard segment was adopted to introduce and optimize the antibacterial activity. This was achieved by synthesizing two types of quaternary ammonium salts (QAS)-containing chain extenders, i.e., N -methyl- N -alkyl- N , N -bis(2-hydroxyethyl) ammonium bromide (M n , where n represents the N -alkyl chain length) and N,N -dimethyl- N -alkyl- N -2,3-propylene glycol (D n ), from N -methyldiethanolamine (MDEA) and 3-dimethylamino-1,2-propanediol (DMAD), respectively. Given the structural differences between M n and D n , main-chain-type PU-M n and side-chain-type PU-D n were subsequently obtained with QAS groups in the hard segment. The N -alkyl chain length, QAS content, and main-/side-chain types were systematically investigated to optimize bactericidal properties. The results revealed that a long N -alkyl chain (from C6 to C14) increased the antibacterial activity of the chain extenders and corresponding TPU films. Besides, side-chain-type PU-D n films showed higher contact-active antibacterial activity than that exerted by the main-chain-type PU-M n films. Remarkably, almost 100% of Staphylococcus aureus ( S . aureus ) could be killed by the PU-D14 film with a low QAS content (1.6 wt %). All the TPUs showed good thermal stability with a degradation temperature of 5% mass loss ( T d,5% ) above 300 °C. Moreover, the TPU films displayed excellent mechanical properties with the tensile strength at break varying from 20.7 to 47.5 MPa and ultimate elongation above 1000%. All of the intrinsic antibacterial films showed negligible hemolytic activities.

Micro/nanorobots (MNRs) hold great promise for various applications due to their capability to execute complex tasks in hard-to-reach micro/nano cavities. However, the developed magnetic MNRs, as marionettes of external magnetic fields, lack built-in intelligence for self-targeting, while chemotactic MNRs suffer from limited self-targeting range. Here, we demonstrate magnetic-chemotactic ZnO/Fe-Ag Janus microrobots (JMRs) capable of rapid, remote self-targeting for bacterial elimination. The JMRs utilize the magnetic Fe engine for coarse navigation from a distance, allowing for external control to swiftly guide them to the vicinity of a hidden/uncharted target that establishes a local chemical gradient ([CO 2 ] or [H + ] gradient). Once in proximity, the inherent chemotaxis of the JMRs takes over, the chemotactic engine enables them to autonomously accumulate at the target site along the chemical gradient in high precision. Upon reaching the target, the ZnO/Fe-Ag JMRs can release Zn 2+ and Ag + to eliminate bacteria residing there. The proposed strategy of integrating on-board chemotaxis with external magnetic field-driven propulsion paves the way for efficient precise therapies using MNRs, especially in targeted drug/energy delivery involving remote hidden or uncharted targets.

Humans use dietary supplements for several intended effects, such as supplementing malnutrition. While these compounds have been developed for host end benefits, their ancillary impact on the gut microbiota remains unclear. The human gut has been proposed as a reservoir for the prevalent lateral transfer of antimicrobial resistance and virulence genes in bacteria through plasmid conjugation. Here, we studied the effect of dietary zinc supplements on the incidence of plasmid conjugation in vitro . Supplement effects were analyzed through standardized broth conjugation assays. The avian pathogenic Escherichia coli (APEC) strain APEC-O2-211 was a donor of the multidrug resistance plasmid pAPEC-O2-211A-ColV, and the human commensal isolate E. coli HS-4 was the plasmid-free recipient. Bacterial strains were standardized and mixed 1:1 and supplemented 1:10 with water, or zinc derived from either commercial zinc supplements or zinc gluconate reagent at varying concentrations. We observed a significant reduction in donors, recipients, and transconjugant populations in conjugations supplemented with zinc, with a dose-dependent relationship. Additionally, we observed a significant reduction ( P < 0.05) in log conjugation efficiency in zinc-treated reactions. Upregulation of the mRNA for the plasmid replication initiation gene repA and the subset of transfer genes M , J , E , K , B , P , C , W , U , N , F , Q , D , I , and X was observed. Furthermore, we observed a downregulation of the conjugal propilin gene traA and the entry exclusion gene traS . This study demonstrates the effect of dietary zinc supplements on the conjugal transfer of a multidrug resistance plasmid between pathogenic and commensal bacteria during in vitro conditions.IMPORTANCEThis study identifies dietary zinc supplementation as a potential novel intervention for mitigating the emergence of multidrug resistance in bacteria, thus preventing antibiotic treatment failure and death in patients and animals. Further studies are required to determine the applicability of this approach in an in vivo model., Competing Interests: The authors declare no conflict of interest.

Osteomyelitis is a severe bone condition caused by bacterial infection that can lead to lifelong disabilities or fatal sepsis. Given that the infection is persistent and penetrates deep into the bone tissue, targeting and rapidly treating osteomyelitis remain a significant challenge. Herein, a triblock targeting peptide featuring ROS-cleavable linkage/antibacterial/bone-targeting unit was grafted onto the macrophage-derived exosomes (RAB-EXO). In vitro , the effective eradication of osteomyelitis pathogens MRSA / E. coli and induction of M2 macrophage differentiation were triggered by RAB-EXO. In vivo , after the intravenous administration of RAB-EXO, it can target the bone tissue and release antimicrobial peptides in the high ROS environment of osteomyelitis. The released antimicrobial peptides markedly inhibit bacterial growth at the infection sites. Moreover, M2 differentiation of the bone tissue macrophages are facilitated by EXO, thereby decreasing the inflammatory factors and achieving the anti-inflammatory effect. Finally, the complete healing of osteomyelitis without adverse effects associated with traditional treatments is achieved within 28 days in rat models. Our findings confirm that RAB-EXO, as a targeted treatment for osteomyelitis, offers promising directions for addressing other bacterial infection diseases, such as periodontitis and rheumatoid arthritis, through similar mechanisms.

Tracheoesophageal voice prostheses (TEPs) are soft polymeric devices used to restore the voices of patients who have undergone total laryngectomy (TL). TEPs are implanted on the tracheoesophageal wall and come in direct contact with food, fluid and air. The environment of an implant is a budding ground for growth of microbes, leading to biofilm formation on the TEP surfaces. Biofilm formation is the leading cause of TEP failure because the biofilm affects its functioning by clogging the air passage over several weeks to a few months. Short useful lifespan of TEPs is a concern for patients undergoing total laryngectomy. To increase the useful lifespan of TEPs, it is imperative to prevent biofilm formation. This problem is addressed in the present study by developing a cationic crosslinked antimicrobial coating that prevents biofilm formation through contact killing. An acrylate-based tetracopolymer poly(methyl methacrylate [MMA]- co-n butyl acrylate [BA]- co -dimethylaminoethyl methacrylate [DMAEMA]- co -2 hydroxyethyl methacrylate [HEMA]) was synthesized by free radical polymerization and was crosslinked by hexamethylene diisocyanate (THDI) trimer through urethane linkages. The crosslinked tetracopolymer coatings were subjected to quaternary ammonium formation through N -alkylation with iodooctane. Different variants of coatings were synthesized and the tetracopolymer with 22.5% MMA, 22.5% BA, 20% HEMA and 35% DMAEMA showed desirable results. The developed coatings were characterized and tested for safety as well as mechanical and antimicrobial efficacy. The final results showed that the developed coatings exhibited good cytocompatibility, haemocompatibility, mechanical properties and antimicrobial properties for 180 days against E. coli , S. aureus and C. albicans.

The study aimed to explore the antimicrobial efficacy of grape seed extract (GSE) and cold atmospheric plasma (CAP) individually or in combination against L. monocytogenes and E. coli wild type (WT) and their isogenic mutants in environmental stress genes. More specifically, we examined the effects of 1% (wt/vol) GSE, 4 min of CAP treatment, and their combined effect on L. monocytogenes 10403S WT and its isogenic mutants Δ sigB , Δ gadD1 , Δ gadD2 , Δ gadD3, as well as E. coli K12 and its isogenic mutants Δ rpoS , Δ oxyR , and Δ dnaK . In addition, the sequence of the combined treatments was tested. A synergistic effect was achieved for all L. monocytogenes strains when exposure to GSE was followed by CAP treatment. However, the same effect was observed against E. coli strains, only for the reversed treatment sequence. Additionally, L. monocytogenes Δ sigB was more sensitive to the individual GSE and the combined GSE/CAP treatment, whereas Δ gadD2 was more sensitive to CAP , as compared to the rest of the mutants under study. Individual GSE exposure was unable to inhibit E. coli strains, and individual CAP treatment resulted in higher inactivation of E. coli in comparison to L. monocytogenes with the strain Δ rpoS appearing the most sensitive among all studied strains. Our findings provide a step toward a better understanding of the mechanisms playing a role in the tolerance/sensitivity of our model Gram-positive and Gram-negative bacteria toward GSE, CAP, and their combination. Therefore, our results contribute to the development of more effective and targeted antimicrobial strategies for sustainable decontamination.IMPORTANCEAlternative approaches to conventional sterilization are gaining interest from the food industry, driven by (i) the consumer demand for minimally processed products and (ii) the need for sustainable, environmentally friendly processing interventions. However, as such alternative approaches are milder than conventional heat sterilization, bacterial pathogens might not be entirely killed by them, which means that they could survive and grow, causing food contamination and health hazards. In this manuscript, we performed a systematic study of the impact of antimicrobials derived from fruit industry waste (grape seed extract) and cold atmospheric plasma on the inactivation/killing as well as the damage of bacterial pathogens and their genetically modified counterparts, for genes linked to the response to environmental stress. Our work provides insights into genes that could be responsible for the bacterial capability to resist/survive those novel treatments, therefore, contributing to the development of more effective and targeted antimicrobial strategies for sustainable decontamination., Competing Interests: The authors declare no conflict of interest.

Many multidrug-resistant (MDR) bacteria have evolved through the accumulation of antibiotic resistance genes (ARGs). Although the potential risk of probiotics as reservoirs of ARGs has been recognized, strategies for blocking the transfer of ARGs while using probiotics have rarely been explored. The probiotic Escherichia coli Nissle 1917 (EcN) has long been used for treating intestinal diseases. Here, we demonstrate frequent transfer of ARGs into EcN both in vitro and in vivo , raising concerns about its potential risk of accumulating antibiotic resistance. Given that no CRISPR-Cas system was found in natural EcN, we integrated the type I-E CRISPR-Cas3 system derived from E. coli BW25113 into EcN. The engineered EcN was able to efficiently cleave multiple ARGs [i.e., mcr-1 , bla NDM-1 , and tet (X)] encoding enzymes for degrading last-resort antibiotics. Through co-incubation of EcN expressing Cas3-Cascade and that expressing Cas9, we showed that the growth of the former strain outcompeted the latter strain, demonstrating a better clinical application prospect of EcN expressing the type I-E CRISPR-Cas3 system. In the intestine of a model animal (i.e., zebrafish), the engineered EcN exhibited immunity against the transfer of CRISPR-targeted ARGs. Our work equips EcN with immunity against the transfer of multiple ARGs by exploiting the exogenous type I-E CRISPR-Cas3 system, thereby reducing the risk of the spread of ARGs while using it as a probiotic chassis for generating living therapeutics., Importance: To reduce the development of antibiotic resistance, probiotics have been considered as a substitute for antibiotics. However, probiotics themselves are reservoirs of antibiotic resistance genes (ARGs). This study introduces a new strategy for limiting the spread of ARGs by engineering the typical probiotic strain Escherichia coli Nissle 1917 (EcN), which has been used for treating intestinal diseases and developed as living therapeutics. We also demonstrate that the type I CRISPR-Cas system imposes a lower growth burden than the type II CRISPR-Cas system, highlighting its promising clinical application potential. Our work not only provides a new strategy for restricting the transfer of ARGs while using probiotics but also enriches the genetic engineering toolbox of EcN, paving the way for the safe use and development of probiotics as living therapeutics., Competing Interests: The authors declare no conflict of interest.

Background: Production of extended-spectrum β-lactamases (ESBLs) is a common resistance mechanism in Enterobacteriaceae, leading to serious hospital-acquired infections. This study aimed to assess phenotypic, phylogenetic, and antibiotic resistance patterns among ESBL-producing Escherichia coli isolates recovered from two rural tertiary hospitals in Thailand., Results: Among 467 Enterobacteriaceae isolates, E. coli was the most prevalent 356 (76.2%) followed by K. pneumoniae 88 (18.8%), K. aerogenes 8 (1.7%), K. variicola 3 (0.6%), K. quasipneumoniae 1 (0.2%%), K. oxytoca 1 (0.2%), and unidentified 9 (1.9%). Of the 202 cephalosporin-resistant E. coli isolates, 195 (96.5%) were ESBL-producing and 7 (3.5%) were non-ESBL-producing. Clermont typing revealed that phylogroup B2 was predominant (43.3%), followed by phylogroups F (11.3%), D (10.3%), C (9.7%), and A (8.7%). Among the beta-lactamase-encoding genes, bla CTX-M (83.6%) and bla TEM (81.0%) were widely found among the isolates, and bla CTX-M-1 (60.7%) was the most common among the five bla CTX-M subgroups detected. The predominant ESBL was bla CTX-M-15 (58.3%). All isolates were resistant to cefotaxime (100%) and ampicillin (100%), followed by ciprofloxacin (91.3 %), ceftazidime (72.8 %), and tetracycline (64.1%)., Conclusion: Our findings show that phylogroup B2 was the most prevalent phylogroup among ESBL-producing E. coli isolates in northeastern Thailand. Notably, the isolates mostly carried the bla CTX-M gene(s)., (© 2024. The Author(s).)

Tetracyclines and glycylcycline are among the important antibiotics used to combat infections caused by multidrug-resistant Gram-negative pathogens. Despite the clinical importance of these antibiotics, their mechanisms of resistance remain unclear. In this study, we elucidated a novel mechanism of resistance to tetracycline and glycylcycline antibiotics via lipopolysaccharide (LPS) modification. Disruption of the Escherichia coli PhoPQ two-component system, which regulates the transcription of various genes involved in magnesium transport and LPS modification, leads to increased susceptibility to tetracycline, minocycline, doxycycline, and tigecycline. These phenotypes are caused by enhanced expression of phosphoethanolamine transferase EptB, which catalyzes the modification of the inner core sugar of LPS. PhoPQ-mediated regulation of EptB expression appears to affect the intracellular transportation of doxycycline. Disruption of EptB increases resistance to tetracycline and glycylcycline antibiotics, whereas the other two phosphoethanolamine transferases, EptA and EptC, that participate in the modification of other LPS residues, are not associated with resistance to tetracyclines and glycylcycline. Overall, our results demonstrated that PhoPQ-mediated modification of a specific residue of LPS by phosphoethanolamine transferase EptB governs intrinsic resistance to tetracycline and glycylcycline antibiotics., Importance: Elucidating the resistance mechanisms of clinically important antibiotics helps in maintaining the clinical efficacy of antibiotics and in the prescription of adequate antibiotic therapy. Although tetracycline and glycylcycline antibiotics are clinically important in combating multidrug-resistant Gram-negative bacterial infections, their mechanisms of resistance are not fully understood. Our research demonstrates that the E. coli PhoPQ two-component system affects resistance to tetracycline and glycylcycline antibiotics by controlling the expression of phosphoethanolamine transferase EptB, which catalyzes the modification of the inner core residue of lipopolysaccharide (LPS). Therefore, our findings highlight a novel resistance mechanism to tetracycline and glycylcycline antibiotics and the physiological significance of LPS core modification in E. coli ., Competing Interests: The authors declare no conflict of interest.

Class II microcins are antimicrobial peptides that have shown some potential as novel antibiotics. However, to date, only 10 class II microcins have been described, and the discovery of novel microcins has been hampered by their short length and high sequence divergence. Here, we ask if we can use numerical embeddings generated by protein large language models to detect microcins in bacterial genome assemblies and whether this method can outperform sequence-based methods such as BLAST. We find that embeddings detect known class II microcins much more reliably than does BLAST and that any two microcins tend to have a small distance in embedding space even though they typically are highly diverged at the sequence level. In data sets of Escherichia coli , Klebsiella spp., and Enterobacter spp. genomes, we further find novel putative microcins that were previously missed by sequence-based search methods., Importance: Antibiotic resistance is becoming an increasingly serious problem in modern medicine, but the development pipeline for conventional antibiotics is not promising. Therefore, alternative approaches to combat bacterial infections are urgently needed. One such approach may be to employ naturally occurring antibacterial peptides produced by bacteria to kill competing bacteria. A promising class of such peptides are class II microcins. However, only a small number of class II microcins have been discovered to date, and the discovery of further such microcins has been hampered by their high sequence divergence and short length, which can cause sequence-based search methods to fail. Here, we demonstrate that a more robust method for microcin discovery can be built on the basis of a protein large language model, and we use this method to identify several putative novel class II microcins., Competing Interests: The authors declare no conflict of interest.

Colibactin, a nonribosomal peptide/polyketide produced by pks+ Enterobacteriaceae , is a virulence factor and putative carcinogen that damages DNA by interstrand crosslinking (ICL). While the clb genes for colibactin biosynthesis have been identified, studies are needed to elucidate the mechanisms regulating colibactin production and activity. Here we perform untargeted metabolomics of pks+ Escherichia coli cultures to identify L-tryptophan as a candidate repressor of colibactin activity. When pks+ E. coli is grown in a minimal medium supplemented with L-tryptophan in vitro ICL of plasmid DNA is reduced by >80%. L-tryptophan does not affect the transcription of clb genes but protects from copper toxicity and triggers the expression of genes to export copper to the periplasm where copper can directly inhibit the ClbP peptidase domain. Thus, L-tryptophan and copper interact and repress colibactin activity, potentially reducing its carcinogenic effects in the intestine., Importance: Colibactin is a small molecule produced by pks + Enterobacteriaceae that damages DNA, leading to oncogenic mutations in human genomes. Colibactin-producing Escherichia coli ( pks +) cells promote tumorigenesis in mouse models of colorectal cancer (CRC) and are elevated in abundance in CRC patient biopsies, making it important to identify the regulatory systems governing colibactin production. Here, we apply a systems biology approach to explore metabolite repression of colibactin production in pks + E. coli . We identify L-tryptophan as a repressor of colibactin genotoxicity that stimulates the expression of genes to export copper to the periplasm where it can inhibit ClbP, the colibactin-activating peptidase. These results work toward an antibiotic-sparing, prophylactic strategy to inhibit colibactin genotoxicity and its tumorigenic effects in the intestine., Competing Interests: The authors declare no conflict of interest.

Antimicrobials reserved for human medicines are permitted for companion animals and it is important to understand multidrug-resistant pathogens recovered from companion animals in terms of epidemiological correlation with human pathogens and possibility of transmission to human-beings. Seventeen of each CTX-M-type extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) and Klebsiella pneumoniae (ESBL-KP) canine isolates were assessed. Entire genomes of the 34 isolates were sequenced. Plasmid transfer and relative growth rates were assessed at differed temperature conditions indicating the body temperature of dogs, that of human-beings, and environment. ESBL-ECs were clonally diverse, while ESBL-KPs were not. The ESBL-ECs carried the bla CTX-M-15 gene in plasmids and the bla CTX-M-14 -like gene either in chromosomes or in plasmids. The ESBL-KPs possessed the bla CTX-M-15 gene in plasmids (n = 15). One of the isolates carried another bla CTX-M-15 gene in a chromosome simultaneously and the other isolate had an additional bla CTX-M-9 gene-harbouring plasmid, together. Two ESBL-KP isolates carried the bla CTX-M-14 gene in plasmids. Plasmid transfer ESBL-EC to K. pneumoniae was efficient and the differed biological costs by temperature was much more in ESBL-EC than in ESBL-KP. Intersectoral dissemination of ESBL-ECs occurred mainly by horizontal gene transfer, while that of ESBL-KPs occurred by clonal dissemination., (© 2024. The Author(s).)

Microbial combating is one of the hot research topics, and finding an alternative strategy is considerably required nowadays. Here, we report on a developed combined chemo- and photodynamic delivery system with a core of zinc oxide nanoparticles (ZnO NPs), porphyrin photosensitizer (POR) connected to alginate polymer (ALG), and berberine (alkaloid natural agent, BER) with favorable antimicrobial effects. According to the achieved main designs, the results demonstrated that the loading capacity and entrapment efficiency reached 22.2 wt % and 95.2%, respectively, for ZnO@ALG-POR/BER nanoformulation (second design) compared to 5.88 wt % and 45.1% for ZnOBER@ALG-POR design (first design). Importantly, when the intended nanoformulations were combined with laser irradiation for 10 min, they showed effective antifungal and antibacterial action against Candida albicans , Escherichia coli , and Staphylococcus aureus . Comparing these treatments to ZnO NPs and free BER, a complete (100%) suppression of bacterial and fungal growth was observed by ZnO@ALG-POR/BER nanoformulation treated E. coli , and by ZnOBER treated C. albicans . Also, after laser treatments, most data showed that E. coli was more sensitive to treatments using nanoformulations than S. aureus . The nanoformulations like ZnOBER@ALG-POR were highly comparable to traditional antibiotics against C. albicans and E. coli before laser application. The results of the cytotoxicity assessment demonstrated that the nanoformulations exhibited moderate biocompatibility on normal human immortalized retinal epithelial (RPE1) cells. Notably, the most biocompatible nanoformulation was ZnOBER@ALG-POR, which possessed ∼9% inhibition of RPE1 cells compared to others. High binding affinities were found between all three microbial strains' receptor proteins and ligands in the molecular docking interaction between the receptor proteins and the ligand molecules (mostly BER and POR). In conclusion, our findings point to the possible use of hybrid nanoplatform delivery systems that combine natural agents and photodynamic therapy into a single therapeutic agent, effectively combating microbial infections. Therapeutic efficiency correlates with nanoformulation design and microorganisms, demonstrating possible optimization for further development.

Infections resulting from microorganisms pose an ongoing global public health challenge, necessitating the constant development of novel antimicrobial approaches. Utilizing photocatalytic materials to generate reactive oxygen species (ROS) presents an appealing strategy for combating microbial threats. In alignment with this perspective, sodium titanate nanotubes were prepared by scalable hydrothermal method using TiO 2 and NaOH. Ag, Au, and Ag/Au-modified titanate nanotubes (TNTs) were prepared by a cost-effective and simple ion-exchange method. All samples were characterized by XRD, FT-IR, HRTEM, and DLS techniques. HRTEM images indicated that the tubular structure was preserved in all TNTs even after the replacement of Na + with Ag + and/or Au 3+ ions. The antibacterial activity in dark and sunlight conditions was evaluated using different bacterial strains, Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa . The results showed that while a low bacterial count (∼log 5 cells per well) was used for inoculation, the TNTs exhibited no antibacterial activity against the three bacterial strains, regardless of whether they were tested under light or dark conditions. However, the plasmonic nanoparticle-decorated TNTs showed remarkable activity in the dark. Additionally, Ag/Au-TNTs demonstrated significantly higher activity in the dark compared with either Ag-TNTs or Au-TNTs alone. Notably, under dark conditions, the Au/Ag-TNTs achieved log reductions of up to 4.5 for P. aeruginosa , 5 for S. aureus , and 3.7 for E. coli . However, when exposed to sunlight, Au/Ag-TNTs resulted in a complete reduction (log reduction ∼9) for P. aeruginosa and E. coli . The combination of two plasmonic nanoparticles (Ag/Au) decorated on the surface of TNTs showed synergetic bactericidal activity under both dark and light conditions. Ag/Au-TNTs could be explored to design surfaces that are responsive to visible light and exhibit antimicrobial properties.

Between 2015 and 2017, 90% of Chinese adults were reported to have periodontitis of varying degrees, highlighting the importance of novel, inexpensive, and affordable treatments for the public. The fact that more and more pathogens are becoming resistant to antibiotics further highlights this prevalence. This article addresses a novel micromotor capable of generating reactive oxygen species, as proven by a Fenton-like reaction. Such reactions allow the targeting of Gram-negative bacteria such as Escherichia coli , which are eliminated order of magnitude more effectively than by pure hydrogen peroxide, thereby addressing pathogens relevant in oral infections. The basis of the micromotors, which generate reactive oxygen species on site, reduces the likelihood of resistance developing in these types of bacteria. Catalytically reducing hydrogen peroxide in this process, these micromotors propel themselves forward. This proof of principle study paves the way for the utilization of micromotors in the field of skin disinfection utilizing hydrogen peroxide concentrations which were in previous works proven noncytotoxic.

Bacterial resistance to antibiotics can negatively affect the treatment of infected skin wounds. The combination of synergistic antibacterial therapies with photodynamic, photothermal, and chemodynamic therapies has been recognized as one of the most promising approaches. In this study, we have developed MSN@Ce6@MnO 2 -CS/Ag (MCMA) nanoparticles to serve as powerful antibacterial agents when exposed to both 660 nm visible light and 808 nm near-infrared (NIR) light. Through dual-light irradiation, MCMA can induce hyperthermia and generate reactive oxygen species (ROS), leading to a remarkable enhancement in photothermal antibacterial effects and accelerating wound healing. It has a peroxidase-like catalytic activity and promotes the generation of hydroxyl radicals (·OH) by catalyzing the decomposition of H 2 O 2 . In vitro antibacterial experiments demonstrated the excellent antibacterial activity of MCMA. The antibacterial efficacy of MCMA at a concentration of 250 μg ml -1 was found to be 99.6 and 100% toward Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli , respectively, under irradiation with an 808 and 660 nm laser. The results of the animal experiments demonstrated that MCMA can effectively accelerate wound healing through wound ulceration inhabitation. These findings substantiate the assertion that synthetic MCMA represents an efficacious strategy for bacterial inhibition and wound healing.

Bacterial infection is one of the major concerns of the growing society, and over the years, different permutations and combinations of various drugs and adjuvants have been attempted, which led to considerable improvements in the efficacy of the antibacterial drugs. In this regard, macrocyclic receptors such as cyclodextrin, cucurbiturils, calixarene, etc., have played a major role by modulating the drug properties that supplement the antibacterial efficacy. In this study, we have developed cucurbit[7]uril (CB7)-functionalized Au nanoparticles (CB7AuNPs) to modulate the activity of an antibiotic, levofloxacin (LOFL). From the spectroscopic and thermodynamic changes in the LOFL, it has been established that two of the prototropic forms, LOFLH and LOFLH 2 + , form strong 1:1 host/guest complexes with CB7/CB7AuNP. Both these interactions led to significant upward shifts in the p K a values as well as photostability of LOFL, thereby enhancing the availability of the active form for the antibacterial activity, at the physiological pH. Further, the LOFL uptake has also been established on CB7AuNP, which retained the CB7-LOFL activity at very low concentration of the CB7 host, functionalized on AuNP. Detailed antibacterial studies of LOFL, both as complexed with CB7 and CB7AuNP, were carried out using four food-borne pathogens ( Escherichia coli , S. Typhimurium , Bacillus cereus, and Staphylococcus aureus ), which revealed a creditable enhancement in the antibacterial property, irrespective of the bacterium strain. These results are quite promising at this stage for the development of drugs customized for multidrug-resistant bacteria.

Wound healing presents a formidable challenge for global healthcare systems. We aimed to address this challenge by designing a multifunctional wound dressing tailored to meet diverse therapeutic needs. Arginine (Arg), selected for its ability to promote wound healing, is grafted onto aldehyde-modified regenerated cellulose (DAC) via Schiff base bonds for a reversible controlled release. At the same time, DAC provides hemostatic function, while Zn 2+ plays an antibacterial role and strengthens cross-linking within the dressing matrix. The hydrogels were characterized by FTIR, XRD, SEM, and EDS. Mechanical strength, adhesion, swelling, water retention, oxygen permeability, hemostasis, antioxidant capacity, and antibacterial activity were all rigorously evaluated to demonstrate the superior properties of the dressing, which promotes accelerated wound healing. The skin of injured mice has been shown to recover almost completely within 13 days of dressing treatment. These findings highlight the potential of this innovative multifunctional wound dressing to address complex wound management challenges.

Infections associated with medical implants due to bacterial adhesion and biofilm formation are a serious problem, leading to acute health risks to patients by compromising their immune system. Therefore, suppressing biofilm formation on biomedical implants is a challenging task, especially for overcoming the drug resistance of bacterial biofilms. Herein, a synergistic efficient surface coating method was developed to inhibit biofilm formation on a model medical implant by combining the antimicrobial property of trimethyl chitosan (TMC) with either 2D material graphene oxide (GO) or black phosphorus (BP) sheets using layer-by-layer (LbL) self-assembly. The multilayer coatings of TMC/GO and TMC/BP were optimized on the glass surface (a model implant) and characterized by using spectroscopic and microscopy techniques. Next, we investigated the antibiofilm formation properties of the TMC/GO and TMC/BP coatings on glass surfaces against both Gram-negative, Escherichia coli ( E. coli ), and Gram-positive, Bacillus subtilis ( B. subtilis ), bacteria. The antibiofilm formation was studied using crystal violet (CV) and live/dead assays. Both the live/dead and the CV assays confirmed that the TMC/2D material (2DM)-coated surfaces prevented biofilm formation much more effectively compared to the uncoated surfaces. Scanning electron microscopy analyses revealed that the bacteria were affected physically by incubating with TMC/2DM-coated surfaces due to membrane perturbation, thereby preventing cell attachment and biofilm formation. Further, BP composite coatings (TMC/BP) showed a much better ability to thwart biofilm formation than GO composite coatings (TMC/GO). Also, multilayer coatings showed superior cytocompatibility with human foreskin fibroblast (HFF). Our results demonstrate that the developed coatings TMC/2DMs could be potential candidates for thwarting biofilm formation on medical implants.

The intricate healing mechanism of chronic wounds and their multitude of healing-related obstacles, such as infections, compromised cellular processes, and impediments to the healing process, pose a significant healthcare problem. Exploration of metal oxide nanoparticles, such as yttrium oxide (Y 2 O 3 ) nanoparticles, can lead to innovative discoveries in the field of chronic wound healing by offering cues that promote cell proliferation in the scaffolds. To achieve this, Y 2 O 3 nanoparticles were synthesized and incorporated within poly(vinyl alcohol) (PVA) nanofibrous scaffolds. Moreover, lysine was infused in the nanofibrous scaffolds to tune its cell adhesion and antimicrobial property. The structure and morphology of the synthesized nanofibers were confirmed through various physicochemical characterizations. Notably, all the fabricated scaffolds have remarkably tuned WVTR values within the range of 2000-2500 g/m 2 /day, favorable for removing the wound exudate, which facilitate the healing process. The scaffolds exhibited substantial antimicrobial property of approximately 68% and 72.2% against both E. coli and S. aureus at optimized Y 2 O 3 loading. They further prevented the formation of biofilm by 68.6% for S. aureus and 51.2% for P. aeruginosa , suggesting the inhibition of recurrent wound infection. The scaffolds illustrated good blood biocompatibility, cytocompatibility, and cell adhesion capabilities. In vitro ROS inhibition study also corroborated the antioxidant property of the scaffold. Similarly, the wound scratching experiment showed high proliferative capability of a yttria-loaded PVA/lysine (S3) sample through the development of an extracellular matrix support. Molecular insight of wound healing was also validated through flow cytometry analysis and immunocytochemistry imaging studies. The findings revealed increased collagen I (Col-I) expression of approximately 19.48% in cultured fibrocytes. The findings are validated from immunocytochemistry imaging. In summary, the results furnish a captivating paradigm for the use of these scaffolds as a therapeutic biomaterial and to foster their potential efficacy toward wound care management.

Recent focus has been directed toward semiconductor nanocrystals owing to their unique physicochemical properties. Nevertheless, the synthesis and characterization of quantum dots (QDs) pose considerable challenges, limiting our understanding of their interactions within a biological environment. This research offers valuable insights into the environmentally friendly production of silver quantum dots (Ag QDs) using lentil extract and clarifies their distinct physicochemical characteristics, previously unexplored to our knowledge. These findings pave the path for potential practical applications. The investigation of the phytochemical-assisted Ag QDs' affinity for BSA demonstrated modest interactions, as shown by the enthalpy and entropy changes as well as the associated Gibbs free energy during their association. Steady-state and time-resolved fluorescence spectroscopy further demonstrated a transient effect involving dynamic quenching, predominantly driven by Forster resonance energy transfer. Additionally, the study highlights the potential broad-spectrum antibacterial activity of Ag QDs (<5 nm, a zeta potential of -3.04 mV), exhibiting a remarkable MIC value of 1 μg/mL against Gram-negative bacteria ( E. coli ) and 1.65 μg/mL against Gram-positive bacteria ( S. aureus ). They can readily enter cells and tissues due to their minuscule size and the right chemical environment. They cause intracellular pathway disruption, which leads to cell death. This outcome emphasizes the distinctive biocompatibility of the green-synthesized Ag QDs, which has been confirmed by their MTT assay-based cytotoxicity against the PC-3 and Wi-38 cell lines.

Infections caused by bacteria that are resistant to many drugs are a major threat to public health in many countries around the world. Here we demonstrate the creation of heterogeneous catalytic nanomaterials with outstanding antimicrobial properties against several superbugs. We have shown that replacing a small amount of copper in a generated copper-phosphate-enzyme nanoflower hybrid with silver drastically increases the antimicrobial capacity of the nanomaterial. In this sense, it has been confirmed that the exchange generated silver phosphate nanoparticles on the Cu nanoflowers, with control of the nanoparticle diameter size. The Fenton catalytic activity of the Ag-containing nanobiohybrids was affected, showing better performance with lower amounts of silver in the final hybrid. This effect was confirmed by their antimicrobial efficacy against Escherichia coli , where the Ag 4 Cu 32 @CALB hybrid displayed a log reduction of 3.9, an efficiency more than 5000 times higher than that obtained with copper nanoflowers (Cu 36 @CALB). The hybrid also showed excellent efficacy against other bacteria such as Klebsiella pneumoniae , Pseudomonas aeruginosa , and Mycobacterium smegmatis with log reductions of 7.6, 4.3, and 1.8, respectively.

Diabetic foot ulcer (DFU) is a common and severe complication of diabetes characterized by wound neuropathy, ischemia, and susceptibility to infection, making its treatment difficult. Dressings are commonly used in treating diabetic wounds; however, they have disadvantages, including lack of flexibility and mechanical strength, lack of coagulation activity, resistance to biodegradation, and low drug delivery efficiency. Developing more effective strategies for diabetic wound treatment has become a new focus. Microneedles (MN) can be used as a drug delivery platform for DFU wounds, allowing safe, effective, painless and minimally invasive medication administration through the skin. Herein, PDA@Ag/SerMA microneedles were prepared by combining the photothermal properties of polydopamine (PDA), the antimicrobial properties of argentum (Ag), and the ability of sericin methacryloyl (SerMA) to promote cell mitosis to accelerate wound healing and treat diabetic ulcer wounds. The results revealed that PDA@Ag/SerMA microneedles exhibited approximately 100% antimicrobial efficacy against Staphylococcus aureus and Escherichia coli under 808 nm near-infrared (NIR) irradiation. Furthermore, the wound healing rate of mice reached 95% within 12 days, which demonstrated the excellent antibacterial properties and wound healing efficacy of PDA@Ag/SerMA microneedles at cellular and animal levels, providing a potential solution for treating DFU.

This paper delves into the intersection of biomaterials and antibacterial agents, highlighting the importance of alginic acid-based biomaterials. We investigate enhancing antibacterial properties by functionalizing alginic acid with an ionic liquid and a potent chelating agent, tris(hydroxypyridinone) (THP). Initial functionalization with the ionic liquid markedly improves the material's antibacterial efficacy. Subsequent functionalization with THP further enhances this activity, reducing the minimum inhibitory concentration from 6 to 3 mg/mL. Notably, the newly developed dual-functionalized materials exhibit no cytotoxic effects at the concentrations tested, underscoring their potential for safe and effective antibacterial applications. These findings highlight the promising role of dual-functionalized alginic acid biomaterials in developing advanced antibacterial treatments.

In this study, we synthesized polyelectrolyte complexed nanoparticles using an ion exchange reaction between poly(hexamethylene guanidine hydrochloride) and sodium caffeate. The morphology of the obtained antiparticle was observed by scanning electron microscopy, and FT-IR and XPS were employed for the structural characterization. The antimicrobial properties of E. coli and S. aureus were characterized through minimum inhibitory concentration (MIC), growth curve analysis, plate colony counting method, and crystal violet method. Notably, the sample showed a 100% bactericidal rate against E. coli at 0.095 μg/mL and against S. aureus at 0.375 μg/mL within 1 h, demonstrating excellent antimicrobial performance against E. coli and S. aureus. The CA-PHMG-containing acrylic resin coatings exhibited exceptional antimicrobial and antiadhesive properties when examined under an inverted fluorescence microscope, particularly at a 4% weight concentration of the antibacterial agent. This study holds vast potential for development in the field of antimicrobial coatings.

Engineered nanomaterials (ENMs) can alter surface properties of cells and disturb cellular functions and gene expression through direct and indirect contact, exerting unintended impacts on human and ecological health. However, the effects of interactions among environmental factors, such as light, surrounding media, and ENM mixtures, on the mechanisms of ENM toxicity, especially at sublethal concentrations, are much less explored and understood. Therefore, we evaluated cell viability and outer membrane permeability of E. coli as a function of exposure to environmentally relevant concentrations of ENMs, including metal (n-Ag) and metal oxide (n-TiO 2 , n-Al 2 O 3 , n-ZnO, n-CuO, and n-SiO 2 ) nanoparticles under dark and simulated sunlight illumination in MOPS, a synthetic buffer, and Lake Michigan Water (LMW), a freshwater medium. We found that light activates the phototoxicity of n-TiO 2 and n-Ag by inducing significant increases in bacterial outer membrane permeability at sublethal doses (< 1 mg/L). Other ENMs, including n-ZnO, n-CuO, n-Al 2 O 3 , and n-SiO 2 , have small to minimal impacts. Toxicities of ENMs were greater in LMW than MOPS due to their different ionic strength and chemical composition. Physical and chemical interactions between n-TiO 2 and n-Ag lead to amplified toxic effects of the ENM mixtures that are greater than the additive effects of individual ENMs acting alone. Our results revealed the significant sublethal bacterial stress exerted by ENMs and ENM mixtures at the cell surface in natural environments at low doses, which can potentially lead to further cellular damage and eventually impact overall ecological health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Accumulation of biofilm over composite resin restorations is one of the principal causes of recurrent caries. Therefore, this study aimed to develop antibacterial composite resins by crystalline selenium nanoparticles (SeNPs), assessing the antibacterial, mechanical, and physical properties of the composite resin after SeNPs incorporation., Methods: SeNPs were synthesized via a green method. The nanoparticles were characterized by UV-Vis spectroscopy, fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The nano-filled composite (Filtek™ Z350XT ) was considered as a control group (G0). Two concentrations of SeNPs (0.005 wt% and 0.01 wt%.) were added to the tested resin composite (G1& G2), respectively. The physical/mechanical and antibacterial properties of the composite specimens (n = 10/group) were characterized. A one-way ANOVA was conducted to analyze these data followed by Bonferroni post hoc test for pairwise comparison., Results: Modified composites with SeNPs showed antibacterial activity against E. coli and S. mutans. Mechanical properties including diametral tensile strength, compressive strength, or surface roughness were not affected by nano-incorporation compared to control. Furthermore, the degree of conversion showed no statistical difference. However, SeNPs incorporation into resin composite produces color change that can be visually perceived., Conclusions: The green synthesized SeNPs significantly improved the antimicrobial properties of the dental composite without compromising mechanical performance. However, it shows color change after SeNPs incorporation., (© 2024. The Author(s).)

Infections with Enterobacterales (E) are increasingly difficult to treat due to antimicrobial resistance. After ceftriaxone replaced chloramphenicol (CHL) as empiric therapy for suspected sepsis in Malawi in 2004, extended-spectrum beta-lactamase (ESBL)-E rapidly emerged. Concurrently, resistance to CHL in Escherichia coli and Klebsiella spp. decreased, raising the possibility of CHL re-introduction. However, many phenotypically susceptible isolates still carry CHL acetyltransferase (cat) genes. To understand the molecular mechanisms and stability of this re-emerging CHL susceptibility we use a combination of genomics, phenotypic susceptibility assays, experimental evolution, and functional assays for CAT activity. Here, we show that of 840 Malawian E. coli and Klebsiella spp. isolates, 31% have discordant CHL susceptibility genotype-phenotype, and we select a subset of 42 isolates for in-depth analysis. Stable degradation of cat genes by insertion sequences leads to re-emergence of CHL susceptibility. Our study suggests that CHL could be reintroduced as a reserve agent for critically ill patients with ESBL-E infections in Malawi and similar settings and highlights the ongoing challenges in inferring antimicrobial resistance from sequence data., (© 2024. The Author(s).)

Irinotecan (CPT-11) is a commonly prescribed chemotherapeutic for the treatment of colon cancer. Unfortunately, acute and delayed diarrhea are prominent side effects of CPT-11 use, and this limits its therapeutic potential. The curative effect of Huangqin decoction (HQD) on chemotherapy-induced diarrhea has been proven. This study investigated the efficacy of the components of HQD (baicalein, baicalin, and paeoniflorin) on CPT-11-induced diarrhea and their underlying mechanisms. Baicalein was found to be the most effective component in improving CPT-11-induced enterotoxicity by intestinal permeability test, ELISA, fluorescence co-localization, and IHC. The combination of baicalin, baicalin and paeoniflorin can obtain similar therapeutic effect to that of HQD. Mendelian randomization analysis, 16 s rRNA sequencing, and fluorescence imaging revealed that baicalein and baicalin significantly inhibited β-glucuronidase (β-GUS) activity. Bacterial abundance analysis and scanning electron microscopy showed that baicalein inhibited the proliferation of Escherichia coli by destroying its cell wall. The molecular dynamics and site-directed mutagenesis results revealed the structural basis for the inhibition of β-GUS by baicalein and baicalin. The results above provide a new idea for the development of drug therapy for adjuvant chemotherapy and theoretical guidance for the optimization of molecular structure targeting β-GUS., (© 2024. The Author(s).)

The present study has been designed to fabricate fungal endophyte-assisted gold nanoparticles (AuNPs) and elucidate their anti-breast cancer potential. The aqueous extract of fungal endophyte Penicillium oxalicum (PO), associated with the medicinal plant Amoora rohituka , was used for the fabrication of AuNPs (POAuNPs). Physico-chemical characterization using Ultraviolet-visible spectroscopy, Fourier transform infrared, X-ray diffraction, Dynamic light scattering, Zeta potential, Transmission electron microscopy and Field emission scanning electron microscopy analysis revealed stable, uniform distribution, spherical shape and crystalline nature of POAuNPs with a size range of 3-46 nm. Furthermore, the POAuNPs potentially inhibited the growth of pathogenic bacterial strains Escherichia coli and Staphylococcus aureus . The synthesized POAuNPs have shown potential antioxidant effects against 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide and nitric oxide (NO) radical scavenging assays with an EC 50 value of 8.875 ± 0.082, 52.593 ± 2.506 and 43.717 ± 1.449 µg mL -1 , respectively. Moreover, the value of EC 50 for the total antioxidant capacity of POAuNPs was found to be 23.667 ± 1.361 µg mL -1 . The cell viability of human breast cancer cells, MDA-MB-231 and MCF-7, was found to be reduced after treatment with POAuNPs, and IC 50 values were found to be 19.753 ± 0.640 and 35.035 ± 0.439 µg mL -1 , respectively. Further, in vitro biochemical assays revealed that POAuNPs induces metabolic reprogramming in terms of reduced glucose uptake, increased lactate dehydrogenase (LDH) release and, disruption of oxidative balance through depletion of glutathione levels, increased nitric oxide (NO) and lipid peroxidation levels as a possible pathway to suppress human breast cancer cell proliferation. Apoptosis-specific nuclear modulations induced by POAuNPs in human breast cancer cells were validated through 4',6-diamidino-2-phenylindole (DAPI) nuclear staining. The present investigation thus attempts to show the first ever fabrication of AuNPs using an aqueous extract of P. oxalicum associated with A. rohituka . The results revealed unique physico-chemical characteristics of mycogenic AuNPs, and screening their effect against breast cancer via metabolic reprogramming and induction of apoptosis thus adds great significance for cancer therapeutics, suggesting further exploration to develop nanotherapeutic drugs., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Multidrug resistance (MDR) considered as global crisis facing poultry industry. Migratory birds play very important role in the dissemination of antimicrobial resistant pathogen during their fly way specially to poultry farms. Therefore, 750 samples from migratory birds and 300 samples from broiler chicken farms and its environment were collected during the winter seasons of five years (2019 to 2023). The samples were subjected to the isolation of Salmonella enterica and Escherichia coli with the detection of antimicrobial resistance (phenotypic and genotypic) with insight to the genetic similarity between the isolates from migratory birds and broiler chickens' farms. Different members of Enterobacteriaceae were isolated; Salmonella enterica, Escherichia coli, Citrobacter, Enterobacter, Klebsiella, Proteus, Providencia, Serratia, Hafnia. 298 (28.4%) of S. enterica strains belonging to 27 serovars. S. Typhimurium, S. Kentucky, S. Enteritidis and S. Shangani were the common 4 serotypes between migratory birds and farms. Meanwhile, we found 489 (46.6%) isolates of E. coli belonging to 24 serogroups and O91, O128, O26, O125, O55, O103 and O159 were the common 7serogroups between migratory birds and farms samples. The majority of Salmonella (91.6%; 274 out of 298) and E. coli (92%; 450 out of 489) were MDR. The MDRI range of Salmonella and E. coli was 0.08- 1.The genetic similarity between the isolates of migratory birds and broiler chicken farms were detected by ERICPCR and hot map. This study suggests the continuous applications of surveillance programs for migratory birds and biosecurity measures in poultry farms., (© 2024. The Author(s).)

Flexible conductive hydrogel-based electronic skin (E-skin) for simultaneous biotherapeutics and sensing applications is one of the current research directions. In this study, conductive and homogeneous silk fibroin/polyaniline/AgNP complexes (SPAg complexes) were prepared with the assistance of silk fibroin, which greatly optimized the compatibility of PANI with the hydrogel matrix. Then, SPAg was introduced into the covalently crosslinked polymer network to prepare poly(acrylamide- co -sulfobetaine methacrylate) - SPAg hydrogels (labeled as PSPAg hydrogels). The PSPAg hydrogels exhibit good biocompatibility, excellent mechanical properties, superb adhesive performance, and fantastic sensing capabilities. Being connected to a smartphone via a Bluetooth system, the SPAg hydrogel-based E-skin was employed to accurately monitor human movements including vigorous joint movements and subtle facial micro-expressions. Finally, benefiting from the synergistic effect of antimicrobial and exogenous electrical stimulation, through promoting angiogenesis and accelerating collagen production in diabetic wounds, PSPAg E-skin successfully facilitates rapid diabetic wound healing. Therefore, the multifunctional PSPAg hydrogel-based E-skin shows great promise for applications in wearable devices and bioelectronics.

This study aimed to design sustained released biodegradable calcium carbonate nanoparticles loaded with chlorhexidine (CHX-loaded NPs) and to investigate the early osteogenic differentiation and antimicrobial effects on the important bacteria involved in infections of dental implants. The microemulsion method was used to prepare the calcium carbonate nanoparticles loaded with chlorhexidine. The prepared nanoparticles were characterized using conventional methods. The release pattern determination and the biodegradation test were performed for the prepared nanoparticles. For the early osteogenic differentiation test of the prepared nanoparticles, alkaline phosphatase (ALP) activity was detected in human dental pulp stem cells (HDPSCs). The antimicrobial effects of the nanoparticles were evaluated against Escherichia coli, Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus, and Pseudomonas aeruginosa. The sizes of free calcium carbonate nanoparticles and CHX-loaded NPs were 105 ± 1.63 and 118 ± 1.47 nm and their zeta potentials were - 27 and - 36, respectively. A 50% degradation of nanoparticles was achieved after 100 days. These nanoparticles showed a two-stage sustained release pattern in vitro. Microscopic images revealed that the morphology of free calcium carbonate nanoparticles primarily took on a spherical calcite form, while CHX-loaded NPs predominantly exhibited a cauliflower-like vaterite polymorph. The nanoparticles increased the activity of ALP in cells in two weeks significantly (p < 0.05). Antimicrobial and antibiofilm results showed an efficient effect of the prepared nanoparticle against the studied bacteria. Calcium carbonate nanoparticles are an efficient multifunctional vector for chlorhexidine and can be used as a bioactive antibacterial agent against various oral microorganisms to prevent implant infections., (© 2024. The Author(s).)

The antimicrobial resistance crisis along with challenges of antimicrobial discovery revealed the vital necessity to develop new antibiotics. Many of the animal proline-rich antimicrobial peptides (PrAMPs) inhibit the process of bacterial translation. Genome projects allowed to identify immune-related genes encoding animal host defense peptides. Here, using genome mining approach, we discovered a family of proline-rich cathelicidins, named rumicidins. The genes encoding these peptides are widespread among ruminant mammals. Biochemical studies indicated that rumicidins effectively inhibited the elongation stage of bacterial translation. The cryo-EM structure of the Escherichia coli 70S ribosome in complex with one of the representatives of the family revealed that the binding site of rumicidins span the ribosomal A-site cleft and the nascent peptide exit tunnel interacting with its constriction point by the conservative Trp23-Phe24 dyad. Bacterial resistance to rumicidins is mediated by knockout of the SbmA transporter or modification of the MacAB-TolC efflux pump. A wide spectrum of antibacterial activity, a high efficacy in the animal infection model, and lack of adverse effects towards human cells in vitro make rumicidins promising molecular scaffolds for development of ribosome-targeting antibiotics., (© 2024. The Author(s).)

Nitric oxide (·NO) is one of the toxic metabolites that bacteria can be exposed to within phagosomes. Gre factors, which are also known as transcript cleavage factors or transcription elongation factors, relieve back-tracked transcription elongation complexes by cleaving nascent RNAs, which allows transcription to resume after stalling. Here we discovered that loss of both Gre factors in Escherichia coli , GreA and GreB, significantly compromised ·NO detoxification due to ·NO-induced phenotypic heterogeneity in Δ greA Δ greB populations, which did not occur in wild-type cultures. Under normal culturing conditions, both wild-type and Δ greA Δ greB synthesized transcripts uniformly, whereas treatment with ·NO led to bimodal transcript levels in Δ greA Δ greB that were unimodal in wild-type. Interestingly, exposure to another toxic metabolite of phagosomes, hydrogen peroxide (H 2 O 2 ), produced analogous results. Furthermore, we showed that loss of Gre factors led to cheating under ·NO stress where transcriptionally deficient cells benefited from the detoxification activities of the transcriptionally proficient subpopulation. Collectively, these results show that loss of Gre factor activities produces phenotypic heterogeneity under ·NO and H 2 O 2 stress that can yield cheating between subpopulations.IMPORTANCEToxic metabolite stress occurs in a broad range of contexts that are important to human health, microbial ecology, and biotechnology, whereas Gre factors are highly conserved throughout the bacterial kingdom. Here we discovered that loss of Gre factors in E. coli leads to phenotypic heterogeneity under ·NO and H 2 O 2 stress, which we further show with ·NO results in cheating between subpopulations. Collectively, these data suggest that Gre factors play a role in coping with toxic metabolite stress, and that loss of Gre factors can produce cheating between neighbors., Competing Interests: The authors declare no conflict of interest.

Guanine nucleotides are required for growth and viability of cells due to their structural role in DNA and RNA, and their regulatory roles in translation, signal transduction, and cell division. The natural antibiotic mycophenolic acid (MPA) targets the rate-limiting step in de novo guanine nucleotide biosynthesis executed by inosine-5´-monophosphate dehydrogenase (IMPDH). MPA is used clinically as an immunosuppressant, but whether in vivo inhibition of bacterial IMPDH (GuaB) is a valid antibacterial strategy is controversial. Here, we describe the discovery of extremely potent small molecule GuaB inhibitors (GuaBi) specific to pathogenic bacteria with a low frequency of on-target spontaneous resistance and bactericidal efficacy in vivo against Acinetobacter baumannii mouse models of infection. The spectrum of GuaBi activity includes multidrug-resistant pathogens that are a critical priority of new antibiotic development. Co-crystal structures of A. baumannii, Staphylococcus aureus , and Escherichia coli GuaB proteins bound to inhibitors show comparable binding modes of GuaBi across species and identifies key binding site residues that are predictive of whole-cell activity across both Gram-positive and Gram-negative clades of Bacteria. The clear in vivo efficacy of these small molecule GuaB inhibitors in a model of A. baumannii infection validates GuaB as an essential antibiotic target., Importance: The emergence of multidrug-resistant bacteria worldwide has renewed interest in discovering antibiotics with novel mechanism of action. For the first time ever, we demonstrate that pharmacological inhibition of de novo guanine biosynthesis is bactericidal in a mouse model of Acinetobacter baumannii infection. Structural analyses of novel inhibitors explain differences in biochemical and whole-cell activity across bacterial clades and underscore why this discovery may have broad translational impact on treatment of the most recalcitrant bacterial infections., Competing Interests: All authors were employed by Genentech, Inc., a member of the Roche Group.

Background: Wound healing is a complex physiological process that can be roughly divided into four stages: hemostasis, inflammation, proliferation, and remodeling. Conventional wound dressings often fail to meet the diverse needs of these healing stages due to their limited functionality. Cryogels, however, possess several attractive properties, such as large, interconnected pores, good mechanical strength, and ease of modification, making them suitable for developing advanced dressings with multiple functions. In this study, we developed a multifunctional cryogel dressing, with biocompatible polysaccharides as the main component, designed to provide a breathable, moist, and antibacterial microenvironment for chronic infected wounds, thereby promoting wound healing., Methods: Recombinant keratin 31 (RK31) was combined with chitosan (CS) to produce a CS/RK31 cryogel, referred to as CK. Gallic acid-reduced silver nanoparticles (GA/Ag NPs) were incorporated as the active antibacterial component to create the CS/K31@GA/Ag cryogel, known as CKGA. The cryogel was characterized using scanning electron microscopy (SEM) and a universal testing machine, and its biocompatibility was assessed in vitro. The dynamic hemostatic performance of the cryogel was evaluated with a rat tail amputation bleeding model. Additionally, the antibacterial effects of the cryogel against Staphylococcus aureus and Escherichia coli were tested using agar diffusion assays and turbidimetry. The antioxidant capacity of the CKGA cryogel was also measured in vitro. Finally, the cryogel's ability to promote wound healing was tested in an SD rat model of infected wounds., Results: Characterization results showed that the CKGA cryogel features an interpenetrating porous network structure and exhibits excellent mechanical properties, with a swelling rate of up to 1800%. Both in vitro and in vivo experiments confirmed that the cryogel has good biocompatibility, effectively absorbs exudates, and rapidly stops bleeding. The addition of GA/Ag NPs provided significant antibacterial effects, achieving an inhibition rate of over 99.9% against both S. aureus and E. coli . Furthermore, CKGA cryogels demonstrated a strong scavenging capacity for ROS in a dose-dependent manner. Studies using the SD rat infected wound model showed that the cryogel effectively inhibited bacterial proliferation on wound surfaces, reduced local tissue inflammation, and promoted the healing of infected wounds., Conclusion: The multifunctional cryogel, with its rapid hemostatic, antibacterial, and antioxidant properties, as well as its ability to promote cell proliferation, could be widely used as a wound dressing for the healing of bacterial infections., Competing Interests: The authors report no conflicts of interest in this work., (© 2024 Miao et al.)

Background: The global threat of multi-drug-resistant bacteria has severely limited the options available for effective antibiotics. This study focuses on the antimicrobial activity and phytochemical characterization of C. oppositifolia extracts, aiming to identify novel plant-based therapeutic agents., Methods: C. oppositifolia specimens-leaves and inflorescence. Specimens were cleaned, sterilized, dried, and ground into a fine powder. Extracts were obtained using methanol and petroleum ether via a Soxhlet apparatus, followed by fractionation with chloroform, n-butanol, and ethyl acetate. Volatile oil was extracted through hydro distillation using a Clevenger apparatus. Phytochemical analysis was conducted to identify bioactive compounds. Biophysical techniques, including UV-visible spectrophotometry, TLC, HPLC, GC-MS, FTIR, and NMR, were employed for characterization. Antimicrobial activity was tested against S. aureus ATCC25922 and E. coli ATCC25922 using agar well and disc diffusion methods, and synergistic effects were assessed with erythromycin and amoxicillin., Results: Methanol extract exhibited bacteriostatic activity with inhibition zones of 13.0 ± 0.2 mm for both S. aureus and E. coli . Petroleum ether, chloroform, n-butanol, and ethyl acetate fractions showed varying inhibition zones. Erythromycin demonstrated bactericidal activity, which was enhanced synergistically when combined with methanol extract and volatile oil, increasing inhibition zones against S. aureus . Phytochemical analysis identified phenols, flavonoids, tannins, coumarins, alkaloids, terpenoids, saponins, and glycosides. FTIR analysis revealed functional groups such as amines, aldehydes, nitriles, alkenes, and sulfones. GC-MS identified 24 compounds, with α-pinene, caryophyllene, and carene as major components. NMR spectra indicated no complex formation between oils and antibiotics, suggesting the compounds act as synergists., Conclusion: The C. oppositifolia extracts possess significant antimicrobial activity and synergistic potential, particularly against S. aureus . The presence of various bioactive compounds suggests a promising role in developing new plant-based therapeutics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Shang et al.)

Background: Urinary tract catheters, including Double-J or ureteral stents, are prone to bacterial colonization forming biofilms and leading to asymptomatic bacteriuria. In the context of asymptomatic bacteriuria, endourological procedures causing mucosa-inducing lesions can lead to severe infections. Antibiotic prophylaxis is warranted, yet its efficacy is limited by biofilm formation on stents. Biofilms promote antibiotic tolerance, the capacity of genetically susceptible bacteria to survive a normally lethal dose of antimicrobial therapy. The UROPOT study evaluates the effectiveness of a first-in-type metabolism-based aminoglycoside potentiation for (i) preventing infectious complications of asymptomatic bacteriuria during mucosa lesion-inducing endourological procedures and (ii) assessing its anti-tolerance efficacy., Methods: The UROPOT trial is a phase I/II single-center (Lausanne University Hospital (CHUV), Switzerland) randomized double-blinded trial. Over 2 years, patients with asymptomatic Escherichia coli and/or Klebsiella pneumoniae bacteriuria, undergoing endourological procedures, will be randomly allocated to one of three treatment arms (1:1:1 randomization ratio, 30 patients per group) to evaluate the efficacy of mannitol-potentiated low-dose amikacin compared to established standard treatments (ceftriaxone or amikacin standard dose). Patients will be recruited at the CHUV Urology Outpatient Clinic. The primary outcome is the comparative incidence of postoperative urinary tract infections (assessed at 48 h) between the investigational amikacin/mannitol therapy and standard (ceftriaxone or amikacin) antibiotic prophylaxis, defined by specific systemic symptoms and/or positive blood and/or urine culture. Secondary outcomes include assessing microbiological eradication through anti-biofilm activity, sustained microbiological eradication, and mannitol and antibiotics pharmacokinetics in blood and urine. Safety outcomes will evaluate the incidence of adverse events following amikacin/mannitol therapy and postoperative surgical complications at postoperative day 14., Discussion: UROPOT tests a novel antimicrobial strategy based on "metabolic potentiation" for prophylaxis enabling aminoglycoside dose reduction and targeting biofilm activity. The anti-biofilm effect may prove beneficial, particularly in patients who have a permanent stent in situ needing recurrent endourological manipulations strategies in preventing infections and achieving sustained microbiological eradication in pre-stented patients., Trial Registration: The protocol is approved by the local ethics committee (CER-VD, 2023-01369, protocole 2.0) and the Swiss Agency for Therapeutic Products (Swissmedic, 701,676) and is registered on the NIH's ClinicalTrials.gov (trial registration number: NCT05761405). Registered on March 07, 2023., (© 2024. The Author(s).)