Antibacterial Action Research Articles

Impact of nitric oxide donors on capsule, biofilm and resistance profiles of Klebsiella pneumoniae

Klebsiella pneumoniae is considered to be a critical public health threat due to its ability to cause fatal, multi-drug-resistant infections in the bloodstream and key organs. The polysaccharide-based capsule layer that shields K. pneumoniae from clearance via innate immunity is a prominent virulence factor. K. pneumoniae also forms biofilms on biotic and abiotic surfaces. These biofilms significantly reduce penetration by, and antibacterial activity from, traditional antibiotics. Nitric oxide (NO), an endogenous molecule involved in the innate immune system, is equally effective at eradicating bacteria but without engendering resistance. This study investigated the effects of NO-releasing small molecules capable of diverse release kinetics on the capsule and biofilm formation characteristics of multiple K. pneumoniae strains. The use of NO donors with moderate and extended NO-release properties (i.e., half-life >1.8 h) inhibited bacterial growth. Additionally, treatment with NO decreased capsule mucoviscosity in K. pneumoniae strains that normally exhibit hypermucoviscosity. The NO donors were also effective against K. pneumoniae biofilms at the same minimum biocidal concentrations that eliminated planktonic bacteria, while meropenem showed little antibacterial action in the same experiments. These results represent the first account of exogenous NO affecting biomarkers involved in K. pneumoniae infections, and may therefore inform future development of NO-based therapeutics for treating such infections.

Understanding the mechanisms behind the antibacterial activity of magnesium hydroxide nanoparticles against sulfate-reducing bacteria in sediments

Nanomaterials, with their small size, surface characteristics, and antibacterial properties, are extensively employed across environmental, energy, biomedical, agricultural, and other industries. This study examined the antibacterial efficacy of magnesium hydroxide (Mg(OH)2) nanoparticles (NPs) against sulfate-reducing bacteria (SRB) within sediments. The inhibitory effects of two types of Mg(OH)2 NPs with distinct particle sizes (20.3 and 29.6 nm) and concentrations (0–10.0 mg/mL) were examined under optimal treatment conditions. The antibacterial mechanisms of Mg(OH)2 NPs through direct contact and dissolution effects were determined. The results revealed a correlation between the concentration, particle size, and inhibitory activity, with the smallest NPs (20.3 nm) at the highest concentration (10.0 mg/mL) substantially reducing SRB counts from 8.77 ± 0.18 to 6.48 ± 0.13 log10 colony forming units/mL after 6 h treatment. Treatment with high concentrations of Mg(OH)2 NPs induced cellular damage, reduced intracellular lactate dehydrogenase activity, and elevated intracellular catalase activity and H2O2 content, suggesting that the contact effect of NPs stimulated SRB. This leads to oxidative stress response and structural damage to the cell membrane, which has emerged as the primary driver of the antibacterial action of Mg(OH)2 NPs. This study presents a novel nanomaterial that can inhibit and control SRB in natural sedimentary environments.

3D-printed porous titanium rods equipped with vancomycin-loaded hydrogels and polycaprolactone membranes for intelligent antibacterial drug release

Implant-related infections pose significant challenges to orthopedic surgeries due to the high risk of severe complications. The widespread use of bioactive prostheses in joint replacements, featuring roughened surfaces and tight integration with the bone marrow cavity, has facilitated bacterial proliferation and complicated treatment. Developing antibacterial coatings for orthopedic implants has been a key research focus in recent years to address this critical issue. Researchers have designed coatings using various materials and antibacterial strategies. In this study, we fabricated 3D-printed porous titanium rods, incorporated vancomycin-loaded mPEG750-b-PCL2500 gel, and coated them with a PCL layer. We then evaluated the antibacterial efficacy through both in vitro and in vivo experiments. Our coating passively inhibits bacterial biofilm formation and actively controls antibiotic release in response to bacterial growth, providing a practical solution for proactive and sustained infection control. This study utilized 3D printing technology to produce porous titanium rod implants simulating bioactive joint prostheses. The porous structure of the titanium rods was used to load a thermoresponsive gel, mPEG750-b-PCL2500 (PEG: polyethylene glycol; PCL: polycaprolactone), serving as a novel drug delivery system carrying vancomycin for controlled antibiotic release. The assembly was then covered with a PCL membrane that inhibits bacterial biofilm formation early in infection and degrades when exposed to lipase solutions, mimicking enzymatic activity during bacterial infections. This setup provides infection-responsive protection and promotes drug release. We investigated the coating’s controlled release, antibacterial capability, and biocompatibility through in vitro experiments. We established a Staphylococcus aureus infection model in rabbits, implanting titanium rods in the femoral medullary cavity. We evaluated the efficacy and safety of the composite coating in preventing implant-related infections using imaging, hematology, and pathology. In vitro experiments demonstrated that the PCL membrane stably protects encapsulated vancomycin during PBS immersion. The PCL membrane rapidly degraded at a lipase concentration of 0.2 mg/mL. The mPEG750-b-PCL2500 gel ensured stable and sustained vancomycin release, inhibiting bacterial growth. We investigated the antibacterial effect of the 3D-printed titanium material, coated with PCL and loaded with mPEG750-b-PCL2500 hydrogel, using a rabbit Staphylococcus aureus infection model. Imaging, hematology, and histopathology confirmed that our composite antibacterial coating exhibited excellent antibacterial effects and infection prevention, with good safety in trials. Our results indicate that the composite antibacterial coating effectively protects vancomycin in the hydrogel from premature release in the absence of bacterial infection. The outer PCL membrane inhibits bacterial growth and prevents biofilm formation. Upon contact with bacterial lipase, the PCL membrane rapidly degrades, releasing vancomycin for antibacterial action. The mPEG750-b-PCL2500 gel provides stable and sustained vancomycin release, prolonging its antibacterial effects. Our composite antibacterial coating demonstrates promising potential for clinical application.

Antibacterial effect and mechanism of theaflavin against Listeria monocytogenes and its application on apple skins.

Theaflavin 3,3'-digallate (TF3), a major polyphenolic component of black tea, exhibits antibacterial effects against many foodborne pathogens. However, the antibacterial mechanisms of TF3 against Listeria monocytogenes remain unclear. In this study, we investigated the effects of TF3 on viability, biofilm, and membrane function of L. monocytogenes by the conventional plating method, crystal violet staining, and microscopy using fluorescent dyes JC-1 and Laurdan, respectively. It was found that TF3 showed excellent antibacterial activity against L. monocytogenes with the minimum inhibitory concentration of 62.5mg/L. The viable count determined on TSA decreased by 3log after the treatment for 2h with TF3 at 62.5mg/L. The viable count determined on TSA containing 4% NaCl decreased by more than 4log after the treatment for 30min with TF3 at the same concentration, suggesting that TF3 gave damage on the cells, enhancing the antibacterial action of 4% NaCl, but the damage was recoverable in the absence of 4% NaCl. To explore the antibacterial mechanisms of TF3, the effects of TF3 on membrane potential and membrane fluidity were investigated. TF3 reduced both membrane potential and fluidity of L. monocytogenes at 62.5mg/L, suggesting that TF3 damaged the structural integrity of the cell membrane. TF3 reduced biofilm mass of mature biofilm of L. monocytogenes. Moreover, THEAFLAVIN TF40, a commercially available Camellia sinensis leaf extract containing TF3, reduced viable count of L. monocytogenes by 2log on apple skin. These results suggest the potential of theaflavins as a natural anti-Listeria disinfectant.

Antibacterial Properties of Cinamaldehyde and its Impact on Biofilm Formation by Respiratory Isolates of Corynebacterium Propinquum

Objective: Analyze the antibacterial properties of cinnamaldehyde (CN) and its effect on biofilm formation by Corynebacterium propinquum. Theoretical Framework: C. propinquum can form biofilm and be multiresistant. In the context of advancing resistance and the need for new and more effective drugs, constituents extracted from cinnamon, such as CN, stand out as they have proven antimicrobial activity. Method: It was investigated whether CN essential oil (EO) was hemolytic for sheep erythrocytes. The antibacterial activity against nasopharyngeal C. propinquum strains was evaluated by determining the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC), and by analyzing the combinatorial effect with chloramphenicol (CL). Biofilm formation on a hydrophobic surface (polystyrene), in the presence or absence of subinhibitory concentrations (SubMIC) of CN, was also evaluated. Results and Discussion: The results demonstrated that CN was not hemolytic. Despite the MIC being higher than that of CL, the antibacterial action was strong for both strains, but it was impossible to determine the MBC. The combinatorial antibacterial effect of CN+CL demonstrated partial synergy or indifference. Weak biofilm formation was observed for the strains and the presence of CN SubMIC, although it did not change the pattern, increased its production. Research Implications: This research's practical and theoretical implications suggest promising antibacterial properties of CN on emerging pathogen C. propinquum. Originality/Value: This study is relevant not only because it demonstrates aspects of virulence of a pathogen that has been little studied, but also because it shows the antibacterial action of CN, a constituent of an easily accessible spice. It highlighted the possibility of future research into the treatment of infections caused by a microorganism that is often multi-resistant.

HPLC-PDA Analysis of Polyacetylene Glucosides from Launaea capitata and Their Antibacterial and Antibiofilm Properties against Klebsiella pneumoniae.

Background/Objectives: Bacterial resistance and virulence are challenges in treating bacterial infections, especially in Klebsiella pneumoniae. Plants of the Launaea Cass. genus are used traditionally to address a variety of diseases, including infections, but the potential bioactive compounds are unknown. Our goals were to verify the potential contribution of two major polyacetylene glycosides isolated from our previous study, (3S,6E,12E)-6,12-tetradecadiene-8,10-diyne-1-ol 3-O-β-D-glucopyranoside (1) and bidensyneoside A (syn. gymnasterkoreaside A) [(3R,8E)-3-hydroxy-8-decene-4,6-diyn-1-yl β-D-glucopyranoside] (2), to the anti-infective properties of Launaea capitata and to develop a dependable HPLC method for their quantification; Methods: On a panel of K. pneumoniae clinical isolates, the antibacterial action of 1, 2, and the methanol extract of the whole L. capitata plant were evaluated by broth microdilution assay, while their antibiofilm action was evaluated by the crystal violet assay. qRT-PCR investigated luxS, mrkA, wzm, and wbbm genes that encode biofilm formation and quorum sensing (QS). The antibacterial activity of 1 was revealed by employing mice infection. Chromatographic separation was conducted using isocratic elution on a Hypersil BDS C18 column using a photodiode array (PDA) detector; Results: Compound 1 showed antibacterial activity with MIC values of 16-128 µg/mL. It remarkably reduced strong and moderate biofilm-forming bacterial isolates from 84.21% to 42.1% compared with the extract (68.42%) and 2 (78.95%). Compound 1 also downregulated the QS genes, luxS, mrkA, wzm, and wbbm, and exhibited in vivo antibacterial action through the enhancement of the histological construction of the liver and spleen, decreased TNF-α immunoreaction, bacterial burden, and the inflammatory mediators IL-1β and IL-6. A successful HPLC-PDA approach was developed to separate the binary mixture of 1 and 2 in less than 10 min with high sensitivity, with detection limits down to 0.518 and 0.095 µg/mL for 1 and 2, respectively; Conclusions: Compound 1 exhibited remarkable antibacterial and antibiofilm properties and may contribute to the anti-infectious traditional uses of L. capitata, meriting further clinical studies and serving as a reliable quality control biomarker for the plant.

ATP synthase of E. coli: F1-ATPase activity is functionally decoupled from the proton-transporting complex (FO) by tributyltin

The F-type ATP synthase/ATPase (FOF1) is important for cellular bioenergetics in eukaryotes and bacteria. We recently showed that venturicidins, a class of macrolides that inhibit the proton transporting complex (FO), can also induce time-dependent functional decoupling of F1-ATPase from FO on membranes from Escherichia coli and Pseudomonas aeruginosa. This dysregulated ATPase activity could deplete bacterial ATP levels and contribute to venturicidin's capacity to enhance the bactericidal action of aminoglycosides antibiotics. We now show that a distinct type of FO inhibitor, tributyltin, also can decouple FOF1-ATPase activity of E. coli membranes. In contrast to the action of venturicidins, decoupling by tributyltin is not dependent on ATP, indicating mechanistic differences. Tributyltin disrupts the coupling role of the ε subunit of F1 but does not induce dissociation of the F1-ATPase complex from membrane-embedded FO. Understanding such decoupling mechanisms could support development of novel antibacterial compounds that target dysregulation of FOF1 functions.

The possibilities of improving the effectiveness of acne therapy

Acne is one of the most urgent problems of dermatology, since this dermatosis is widespread, often occurs during puberty, is accompanied by cosmetic defects, causes increased anxiety, dysmorphic phobia and depressive states. As a result, the quality of life and the possibility of social adaptation decrease in patients. Therefore, it is necessary to optimize the treatment of this disease with the inclusion of modern highly effective drugs. When prescribing treatment, it is necessary to take into account all links in the pathogenesis of acne, and also remember that inflammation plays an important role in the development of dermatosis (especially severe course). With mild acne, it is recommended to prescribe only external therapy, with medium – external therapy and, if necessary, systemic, with severe systemic therapy is used as the main one. The appointment of antibiotics for this dermatosis is dictated by the presence of bacterial flora. Clindamycin is one of the antibiotics that effectively reduce colonization of C. аcnes. To ensure the high efficiency and safety of topical therapy, as well as the prevention of the development of resistance of microorganisms, there is a need to use a combination of at least two drugs. Thus, the combination of clindamycin with benzoyl peroxide makes it possible to increase the effectiveness of therapy due to bactericidal, bacteriostatic, anti-inflammatory and keratolytic actions. The convenient mode of use and the rapid therapeutic effect make it possible to include this combination in the group of priority drugs for the treatment of acne. Comedonolytic, anti-inflammatory and bactericidal effects are also observed in azelaic acid, and therefore drugs containing this component show a high pathogenetic effect in acne.

Algorithms for topical therapy of mycoses at the daily appointment of a dermatologist

This article discusses the immediacy of the problem of rising incidence of common mycoses that dermatovenerologists deal with at outpatient visits, the reasons for their occurrence, conversion from one course of the disease to another and the use of etiological effective treatments. The author described the mechanisms of development of different mycoses according to their etiology, comorbid disorders accompanying mycoses and the features of the clinical picture based on etiological factors and sites of infection. The article places special emphasis on the reasons for infection with fungal invasions in humans, conditions and numerous contact routes. Modern features of the course of fungal skin diseases include formation of biofilms in the sites of infection, multicentricity, extension of the pathological process, frequent formation of granulomas, follicles, occurrence of numerous mycoides, as well as the low virulence of dermatophytes. The publication also presents various clinical cases of somatically healthy patients suffering from various mycoses caused by variant factors, which have pathological processes located in different sites. According to the doctor’s prescription, patients used conventional treatment regimens that included external/ topical treatment and general therapy, strictly in accordance with clinical guidelines – the use of highly active broad-spectrum antifungal drugs with fungicidal, fungistatic, antibacterial, anti-inflammatory and antipruritic action. These properties ensure a low probability resistance of microorganisms or relapses during treatment with topical dosage forms of antifungal drugs for cutaneous application. Upon completion of the course of treatment, patients reported a significant improvement in their skin condition resulting in minimization of disease symptoms, disappearance of skin rashes, skin itching, and elimination of exfoliation.

Inhibitory effect and mechanism of violacein on planktonic growth, spore germination, biofilm formation and toxin production of Bacillus cereus and its application in grass carp preservation

Bacillus cereus is a ubiquitous foodborne pathogen commonly found in various foods. Its ability to form spores, biofilms and diarrhoeal and/or emetic toxins further exacerbates the risk of food poisoning. Violacein is a tryptophan derivative with excellent antibacterial activity. However, the knowledge on the antibacterial action of violacein against B. cereus was lacking, and thus this study aimed to investigate the antibacterial activity and mechanism. The antibacterial results demonstrated that minimum inhibitory concentration and minimum bactericidal concentration of violacein were 3.125 mg/L and 12.50 mg/L, respectively. Violacein could effectively inhibit planktonic growth, spore germination and biofilm formation of B. cereus (P < 0.001). Meanwhile, violacein significantly downregulated the expression of toxin genes, including nheA (P < 0.05), nheB (P < 0.001), bceT (P < 0.01), cytK (P < 0.001), hblC (P < 0.001) and hblD (P < 0.001). Results of extracellular alkaline phosphatase, nucleotide and protein leakage assays and scanning and transmission electron microscopy observation tests showed violacein destroyed cell walls and membranes of B. cereus. In addition, 6.25 mg/kg of violacein could significantly inhibit B. cereus in grass carp fillets (P < 0.05). These results demonstrate that violacein has great potential as an effective natural antimicrobial preservative to control food contamination and poisoning events caused by B. cereus.

3D Bilayered Hydrogel and Nanofiber Multifunctional Sponge Dressing: An Efficacious Healing Agent for Chronic Wound Healing.

Chronic wound management using biomaterial-based dressings has significantly impacted the standard and efficiency of wound healing. However, various available wound healing aids are ineffective in treating deep open injuries and chronic wounds such as diabetic wounds. Herein, we developed a 3D bilayered multifunctional sponge, which addresses the structural and functional issues faced by biomaterial dressings in treating deep and chronic wounds. The 3D bilayered sponge consists of a hydrogel base functionalized with wound healing peptide (Tylotoin)-carrying nanoparticles and topped with a nanofiber layer functionalized with an antimicrobial peptide (LLKKK18). The 3D bilayered sponge, with its highly porous, elastic, and enhanced fluid absorption ability, makes it a suitable wound treatment aid. The developed multifunctional 3D sponge shows antibacterial action and promotes a microenvironment similar to the extracellular matrix (ECM) in regulating dermal cell survival and migration. Study in a full-thickness skin defect diabetic mouse model has shown that the developed 3D bilayered sponge accelerated wound closure and promoted functional skin regeneration through reduced inflammation, faster granulation tissue formation, re-epithelialization, neovascularization, and skin appendage restoration, which make the developed 3D bilayered multifunctional sponge an efficient and advanced chronic wound management aid with potential for future clinical application.

A two-in-one molybdenum disulfide-chitosan nanoparticles system for activating plant defense mechanisms and reactive oxygen species to treat Citrus Huanglongbing

Citrus Huanglongbing (HLB) poses an enormous challenge to Citrus cultivation worldwide, necessitating groundbreaking interventions beyond conventional pharmaceutical methods. In this study, we propose molybdenum disulfide-chitosan nanoparticles (MoS2-CS NPs) through electrostatic adsorption, preserving the plant-beneficial properties of molybdenum disulfide (MoS2), while enhancing its antibacterial effectiveness through chitosan modification. MoS2-CS NPs exhibited significant antibacterial efficacy against RM1021, and the closest relatives to Candidatus Liberibacter asiaticus (CLas), Erwinia carotovora, and Xanthomonas citri achieved survival rates of 7.40 % ± 1.74 %, 8.94 % ± 1.40 %, and 6.41 % ± 0.56 %, respectively. In vivo results showed, CLas survival rate of 10.42 % ± 3.51 %. Furthermore, treatment with MoS2-CS NPs resulted in an increase in chlorophyll and carotenoid content. Concomitantly, a significant reduction in malondialdehyde (MDA), soluble sugar, hydrogen peroxide (H2O2), and starch contents was also observed. Mechanistically, MoS2-CS NPs enhanced the activity of antioxidant-related enzymes by upregulating the expression of antioxidant genes, thereby galvanizing the antioxidant system to alleviate oxidative stress. Collectively, this dual functionality—combining direct antibacterial action with the activation of plant defense mechanisms—marks a promising strategy for managing Citrus Huanglongbing and suggests potential agricultural applications for MoS2-based antibacterial treatments.

Enhanced Nitric Oxide Delivery Through Self-Assembling Nanoparticles for Eradicating Gram-Negative Bacteria.

In the current battle against antibiotic resistance, the resilience of Gram-negative bacteria against traditional antibiotics is due not only to their protective outer membranes but also to mechanisms like efflux pumps and enzymatic degradation of drugs, underscores the urgent need for innovative antimicrobial tactics. Herein, this study presents an innovative method involving the synthesis of three furoxan derivatives engineered to self-assemble into nitric oxide (NO) donor nanoparticles (FuNPs). These FuNPs, notably supplied together with polymyxin B (PMB), achieve markedly enhanced bactericidal efficacy against a wide spectrum of bacterial phenotypes at considerably lower NO concentrations (0.1-2.8µgmL-1), which is at least ten times lower than the reported data for NO donors (≥200µgmL-1). The bactericidal mechanism is elucidated using confocal, scanning, and transmission electron microscopy techniques. Neutron reflectometry confirms that FuNPs initiate membrane disruption by specifically engaging with the polysaccharides on bacterial surfaces, causing structural perturbations. Subsequently, PMB binds to lipid A on the outer membrane, enhancing permeability and resulting in a synergistic bactericidal action with FuNPs. This pioneering strategy underscores the utility of self-assembly in NO delivery as a groundbreaking paradigm to circumvent traditional antibiotic resistance barriers, marking a significant leap forward in the development of next-generation antimicrobial agents.

Synthesis of Inonotus rickii metabolite-loaded chitosan nanoparticles and its biological activities

Inonotus rickii, a mushroom fungus classified as a Hyamenochetae, is commonly observed in the Western Ghats region of Maharashtra, India. The metabolites extracted from this mushroom exhibit various biological activities. On the other side, currently chitosan nanoparticles emerging as an effective nanocarrier for targeted treatments. Therefore in the present study nanoparticles from biopolymer chitosan loaded with I. rickii metabolites of different solvent extract were synthesized and their antioxidant, antibacterial and anticancer potential were evaluated. The synthesized NPs were spherical in shape, and the average size for pure chitosan nanoparticles (CHI-NPs) was 58.02 nm, I. rickii aqueous CHI-NPs (U2-Aq-CHI-NPs) 62.70 nm, I. rickii acetone CHI-NPs (U2-Ac-CHI-NPs) 17.11 nm, and I. rickii ethanol CHI-NPs (U2-Et-CHI-NPs) 27.05 nm. These I. rickii metabolite-loaded CHI-NPs exhibited antibacterial, antioxidant, and cytotoxic activities. The U2-Ac-CHI-NPs showed significant antibacterial actions against four bacterial strains such as E. coli, Bacillus cereus, Pseudomonas otitidis, and Chryseobacterium spp. It also showed significantly higher antioxidant activity (95.8±1.6 %). Moreover, a significant decrease in the cell viability of the HeLa cell line was noticed with a subsequent increase (1–1000 µg/mL) in the concentration of metabolite-loaded CHI-NPs. A U2-Aq-CHI-NPs lower concentration is also significant to decrease cell viability. The LC-MS analysis revealed the presence of different bioactive compounds like Hispolon, Inoscavins, Methyl inoscavins, and Phelligridins in all tested extracts of I. rickii supports the bioactivities. Therefore, the synergistic effect of I. rickii-derived metabolite-loaded CHI-NPs suggested a significant perspective for the targeted drug delivery-based treatment with diminished side effects.

Blood-responsive mussel-inspired hydrogels for hemostasis, antibacterial action, and wound healing

Rapid hemostasis, potent antimicrobial activity, and efficient wound management are critical factors in enhancing the survival of trauma patients. Chitosan, as a green and sustainable biomaterial with low cost, degradability and biocompatibility, is widely used in the biomedical field. However, chitosan dissolves in an acidic environment, which is not conducive to wound healing. In this study, chitosan was chemically modified to address this limitation. A mussel-inspired hydrogel composed of caffeic acid-grafted chitosan, gallic acid-grafted chitosan, and oxidized microcrystalline cellulose (CHI-C/CSG/OMCC) was designed. This hydrogel exhibits blood-responsive gelation behavior and offers a synergistic combination of tissue adhesion, antimicrobial properties, and tissue repair capabilities. The carboxyl, hydroxyl, phenolic hydroxyl and aldehyde groups within the hydrogel system endowed the hydrogel with excellent adhesion properties (53.1 kPa adhesion strength to porcine skin-adherent tissues), biocompatibility, and excellent antimicrobial properties. Surprisingly, this hydrogel not only achieved rapid and effective hemostasis, but also effectively promoted wound healing in a mouse skin injury model. In addition, its remarkable efficacy in stopping bleeding within approximately 2 min without rebleeding was demonstrated in a porcine model of acute gastrointestinal hemorrhage in the esophagus, stomach, and intestines. This blood-responsive ternary hydrogel offers a promising alternative to wound management materials due to its excellent overall performance and superior efficacy in all phases of wound healing.

Antibacterial and Anticorrosive Hydrogel Coating Based on Complementary Functions of Sodium Alginate and g-C3N4.

Graphitic carbon nitride (g-C3N4, CN) has emerged as a promising photocatalytic material due to its inherent stability, antibacterial properties, and eco-friendliness. However, its tendency to aggregate and limited dispersion hinder its efficacy in practical antibacterial applications. To address these limitations, this study focuses on developing a composite hydrogel coating, in which sodium alginate (SA) molecules interact electrostatically and through hydrogen bonding to anchor CN, thereby significantly improving its dispersion. The optimal CN loading of 35% results in a hydrogel with a tensile strength of 120 MPa and an antibacterial rate of 99.87% within 6 h. The enhanced mechanical properties are attributed to hydrogen bonding between the -NH2 groups of CN and the -OH groups of SA, while the -OH groups of SA facilitate the attraction of photogenerated holes from CN, promoting carrier transfer and separation, thereby strengthening the antibacterial action. Moreover, the hydrogel coating exhibits excellent antibacterial and corrosion resistance capabilities against Pseudomonas aeruginosa on 316L stainless steel (316L SS), laying the foundation for advanced antimicrobial and anticorrosion hydrogel systems.

Antibacterial action, proteolytic immunity, and in vivo activity of a Vibrio cholerae microcin

Microcins are small antibacterial proteins that mediate interbacterial competition. Their narrow-spectrum activity provides opportunities to discover microbiome-sparing treatments. However, microcins have been found almost exclusively in Enterobacteriaceae. Their broader existence and potential implications in other pathogens remain unclear. Here, we identify and characterize a microcin active against pathogenic Vibrio cholerae: MvcC. We show that MvcC is reliant on the outer membrane porin OmpT to cross the outer membrane. MvcC then binds the periplasmic protein OppA to reach and disrupt the cytoplasmic membrane. We demonstrate that MvcC's cognate immunity protein is a protease, which precisely cleaves MvcC to neutralize its activity. Importantly, we show that MvcC is active against diverse cholera isolates and in a mouse model of V.cholerae colonization. Our results provide a detailed analysis of a microcin outside of Enterobacteriaceae and its potential to influence V.cholerae infection.

Targeted Hybridization: Pyrazine‐2‐Carbohydrazide Derivatives as Promising Antitubercular and Antimicrobial Leads

AbstractIn an attempt to identify a new pharmacological lead which should be more potent than the established drug pyrazinamide, a molecular hybridization technique was applied to fuse two pharmacophore moieties: pyrazine‐2‐carbohydrazide (1) and diphenyl ether/piperazinyl derivative (2), to isolate a new series of hybrid molecules. The synthesized compounds were tested in vitro for their antibacterial and antimycobacterial properties against E. coli and S. aureus and Mycobacterium TB H37Rv strains. In comparison to the reference medication (pyrazinamide) these compounds exhibited moderate antitubercular and antibacterial action, with a MIC value of 15.625–125 µg/mL. All the synthesized molecules were characterized through IR, NMR and mass spectrometry. Docking studies were carried out in order to have better understanding related to protein and ligand receptor interactions.

Cefotaxime Versus Ceftriaxone: A Comprehensive Comparative Review.

Cefotaxime and ceftriaxone are two prominent third-generation cephalosporin antibiotics, which are a class of antimicrobial agents with overlapping antibacterial spectra and therapeutic indications, commonly used in treating severe bacterial infections, including meningitis, sepsis, and respiratory tract infections. Despite their shared antibacterial coverage, these antibiotics differ significantly in their pharmacokinetic characteristics such as half-life, protein binding, and tissue penetration. This comprehensive review systematically compares the pharmacokinetic profiles, pharmacological attributes, clinical efficacy, and safety profiles of cefotaxime and ceftriaxone. It further highlights the importance of understanding the nuanced differences between cefotaxime and ceftriaxone, particularly in clinical settings such as intensive care units or during pediatric treatment, where rapid bactericidal action or prolonged drug activity might influence therapeutic outcomes. While their overlapping spectrums offer versatility, clinicians should consider these distinct pharmacokinetic attributes and associated clinical outcomes to guide optimal antibiotic selection.

Berberine-loaded nanoemulsions as a natural food preservative; the impact of femtosecond laser irradiation on the antibacterial activity

There is a growing concern among food safety regulators, the food industry, and consumers about foodborne illnesses. To improve food safety and increase shelf life, it is necessary to use natural preservatives. Natural antimicrobials are safer than artificial preservatives because they can prevent microbial resistance while also meeting consumers' demands for healthier food. This study used Berberine to enhance the antibacterial activity of Satureja Khuzistanica essential oil nanoemulsions (SKEO NE) against Staphylococcus aureus (S. aureus) bacteria, making them a promising option as preservatives. Response Surface Methodology (RSM) was employed to determine the optimized Berberine loaded SKEO NE (Berberine/SKEO NE), resulting in a mean droplet size of 88.60 nm at 6.91, 3.21, and 0.08% w/w of surfactant, essential oil, and Berberine, respectively. Berberine utilization in SKEO NE has led to an increase in antibacterial activity. The nanoemulsion samples significantly ruptured the S. aureus bacterial cell membrane, rapidly discharging cell contents. The use of a microfluidic system in tandem based on the conventional approach significantly accelerated this process. Enhancing the interaction between nanodroplets and the bacterial membrane can be achieved through the nanoemulsification process of EOs, which involves modifying their surface characteristics. This enhancement is particularly pronounced when employing microfluidic systems due to their substantial contact surface area. We investigated the potential of using femtosecond laser irradiation at a wavelength of 1040 nm to augment the antibacterial action of nanoemulsions. The combined treatment of laser and nanoemulsions significantly increased the antibacterial effect of nanoemulsions by approximately 15% for each bacterium, suggesting the potential utility of this treatment to bolster the antibacterial activity of nanoemulsions. Bacteria were trapped using optical tweezers for up to 20 min, with bacterial destruction observed starting at 3 min and exhaustive destruction evident after 20 min.