Inhibition Of Bacterial Growth Research Articles

Novel structural determinants and bacterial death-related regulatory effects of the scorpion defensin BmKDfsin4 against gram-positive bacteria.

Numerous defensins constitute a family of cationic antimicrobial peptides with high degrees of sequence variability, and in-depth characterization of their structural basis and antibacterial mechanisms remains limited. Here, a representative scorpion defensin, BmKDfsin4, with two distinct hydrophobic and basic residue clusters, was extensively investigated. The hydrophobic residue cluster, formed by Phe2, Pro5, Phe6, Phe28 and Leu29 residues, strongly influences the antibacterial activity of BmKDfsin4 against Gram-positive bacteria. Compared with the three scattered Lys13, Lys30 and Arg32 residues, the basic residue cluster, consisting of the Arg19, Arg20, Arg21 and Arg37 residues, played a less important role. The synergistic interaction between the basic residue cluster and Arg32 significantly affected BmKDfsin4 function. The bacterial growth inhibition by BmKDfsin4 was associated with regulating expression levels of cell division-related genes, cell wall synthesis-related genes and bacterial autolysis-related genes rather than destroying the bacterial cell membrane. The coincubation of BmKDfsin4 with the bacterial strains induced gradual changes in the bacterial surface from a rough and thin surface to a noticeably wrinkled surface together with abundant white spots and even complete cavities within the bacteria. These findings revealed novel structural determinants and bacterial death-related regulatory effects of the defensin BmKDfsin4 and highlighted diverse antibacterial mechanisms of defensins.

Macrophage Immunomodulation and Suppression of Bacterial Growth by Polydimethylsiloxane Surface-Interrupted Microlines’ Topography Targeting Breast Implant Applications

Since breast cancer is one of the most common forms of cancer in women, silicone mammary implants have been extensively employed in numerous breast reconstruction procedures. However, despite the crucial role they play, their interaction with the host’s immune system and microbiome is poorly understood. Considering this, the present work investigates the immunomodulatory and bacterial mitigation potential of six textured surfaces, based on linear step-like features with various regular and irregular multiscaled arrangements, in comparison to a flat PDMS surface. We hypothesise that the chosen surface geometries are capable of modulating the cellular response through mechanical interdigitation within the multiscaled surface morphology, independent of the surface chemical properties. Each type of sample was characterised from a physico-chemical and biological points of view and by comparison to the flat PDMS surface. The overall results proved that the presence of linear multiscaled step-like features on the PDMS surface influenced both the surface’s characteristics (e.g., surface energy, wettability, and roughness parameters), as well as the cellular response. Thus, the biological evaluation revealed that, to different degrees, biomaterial-induced macrophage activation can be mitigated by the newly designed microtextured surfaces. Moreover, the reduction in bacteria adherence up to 90%, suggested that the topographical altered surfaces are capable of suppressing bacterial colonisation, therefore demonstrating that in a surgical environment at risk of bacterial contamination, they can be better tolerated.

A, the synthesis and evaluation of Polyvinyl Alcohol/Silver Nanoparticles (PVA/AgNPs) via electrochemical method: a model test for antioxidant and antibacterial activities

Background: Silver nanoparticles that are artificially created have electrochemical properties that work as antibacterial agents and are widely used in several areas ofresearch. Purpose: This work aimed to generate silver nanoparticles by the electrochemical method, using PVA as a stabilizer, and assess their antioxidant and antibacterial characteristics. Experimental procedures: Silver nanoparticles were synthesized using an electrochemical method, utilizing a stabilized polyvinyl alcohol solution at a concentration of 1 g/L. The validation of the PVA/AgNPs synthesis was performed using a UV-Vis spectrophotometer. The AgNPs were characterized by FT-IR, DLS, Zeta potential, and AFM. The antioxidant capabilities of PVA/AgNPs were assessed utilizing DPPH methods. The antibacterial activity of PVA/AgNPs against Salmonella enterica, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis was assessed using the bacterial growth inhibition method. An assessment was conducted to determine the susceptibility of silver nanoparticles to limit the growth of microorganisms, as well as to determine the lowest concentration required to achieve this inhibitory effect. Results: The results confirmed that the AgNPs were generated by the electrochemical method with the assistance of a PVA stabilizer. The nanosilver had a mean particle size of 53.1 nm. The antioxidant experiments revealed that PVA/AgNPs exhibit more antioxidant activity than ascorbic acid at higher dosages. PVA/AgNPs exhibit substantial antibacterial effectiveness. The minimum inhibitory concentration (MIC) of PVA/AgNPs against E.coli, S.enterica, S.aureus, and B.subtilis was found to be 12.5 μg/mL. Conclusion: The bioactive chemicals found on the surface of AgNPs are responsible for the antioxidant and antibacterial characteristics of electrochemical PVA/AgNPs composites.

Smart conducting polymer innovations for sustainable and safe food packaging technologies.

Biofilm formation on food packaging surfaces is a major issue in the industry, as it leads to contamination, reduces shelf life, and poses risks to human health. To mitigate these effects, developing smart coatings that can actively sense and combat microbial growth has become a critical research focus. This study is motivated by the need for intelligent packaging solutions that integrate antimicrobial agents and sensors for real-time contamination detection. It is hypothesized that combining conducting polymers (CPs) with nanomaterials can enhance antimicrobial efficacy while maintaining the mechanical integrity and environmental stability required for food packaging applications. Through the application of numerous technologies like surface modification, CP-nanoparticle integration, and multilayered coating, the antimicrobial performance and sensor capabilities of these materials were analyzed. Case studies showed a 90% inhibition of bacterial growth and a tenfold decrease in viable bacterial counts with AgNPs incorporation, extending strawberries' shelf life by 40% and maintaining fish freshness for an additional 5 days. Moreover, multilayered CP coatings in complex systems have been shown to reduce oxidative spoilage in nuts and dried fruits by up to 85%, while maintaining the quality of leafy greens for up to 3 weeks under suboptimal conditions. Environmental assessments indicated a 30% reduction in carbon footprint when CP coatings were combined with biodegradable polymers, contributing to a more transparent and reliable food supply chain. CP-based films integrated with intelligent sensors exhibit high sensitivity, detecting ammonia concentrations below 500ppb, and offer significant selectivity for sensing hazardous gases. These findings indicate that CP-based smart coatings markedly enhance food safety and sustainability in packaging applications.

Medical-grade honey has superior antibacterial properties against common bacterial isolates in wound cultures of dogs and cats in comparison to non-medical-grade honey types.

To compare the antibacterial activities of different types of honey against common bacterial isolates cultured from wounds of dogs and cats. 4 types of honey were used including a medical-grade manuka honey, a non-medical-grade manuka honey, a locally sourced non-medical-grade honey (non-MGH), and a commercially sourced non-MGH. Bacterial isolates were obtained from clinical wound cultures of dogs and cats including Staphylococcus pseudintermedius, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa. The macro-broth dilution method was used to analyze the MIC and minimum bactericidal concentration. The percentage of growth inhibition was assessed for different types of honey at different concentrations using a generalized linear regression model. Medical-grade honey exhibited the lowest minimum bactericidal concentration against S pseudintermedius, E faecalis, and P aeruginosa, alongside the lowest MIC at 90% with statistically significant higher bacterial growth inhibition in medium and low concentrations. Non-medical-grade manuka honey had a similar bactericidal activity against S pseudintermedius and P aeruginosa compared to locally and commercially sourced non-MGH. In this in vitro study, MGH exhibited superior antibacterial activity against all bacterial isolates compared to other types of honey. Medical-grade honey displayed the greatest antibacterial activity against common wound pathogens and could be considered over other types of honey for wound management in cats and dogs. Locally and commercially sourced non-MGH appears to have a comparative efficacy against certain bacteria compared to non-medical-grade manuka honey and is more cost effective. Further in vivo studies are needed to confirm these findings.

Silver nanoparticles exhibit in vitro anthelmintic and antimicrobial activities against Dactylogyrus minutus (Kulwieć, 1927), and Aeromonas hydrophila in Cyprinus carpio Koi

The study aimed to evaluate the in vitro anthelminthic and antimicrobial activity of silver nanoparticles (AgNPs) against Dactylogyrus minutus and Aeromonas hydrophila, pathogens of Cyprinus carpio Koi. Gill arches of the fish were removed and placed into six-well plates containing 10 mL of tank water with varying concentrations of AgNPs: 100, 400, 500, 600, and 800 mg/L, along with control groups using tank water and distilled water. Each group was tested in triplicate. Parasites were observed every 10 min for 300 min (5 h) using a stereomicroscope, and mortality rates were recorded. Anthelminthic efficacy was calculated at the end of the tests. For the in vitro antimicrobial test, the Minimum Inhibitory Concentration (MIC) of AgNPs was determined by adding 100 μL of Poor Broth (PB) culture medium to all 96 wells of a microplate. The first well was filled with 100 μL of AgNPs, followed by serial dilutions (1:2 ratio). Subsequently, 50 μL of A. hydrophila (1 × 107 CFU/mL) was added to all wells and incubated for 24 h at 28 °C. Results showed that 800 mg/L of AgNPs achieved 87% anthelminthic efficacy within 300 min, while 100 mg/L achieved 47% efficacy. The MIC showed bacterial growth inhibition at 125 mg/mL. Despite the 87% efficacy against parasites within 300 min, AgNPs did not reach 100% efficacy quickly, limiting their potential use in ornamental fish farming. Further studies are needed to assess the toxicity of AgNPs in fish.

Synthesis of metal nanoparticles on graphene oxide and antibacterial properties.

Pathogen-induced infections and the rise of antibiotic-resistant bacteria, such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), pose significant global health challenges, emphasizing the need for new antimicrobial strategies. In this study, we synthesized graphene oxide (GO)-based composites functionalized with silver nanoparticles (AgNPs) and copper nanoparticles (CuNPs) as potential alternatives to traditional antibiotics. The objective is to assess the antibacterial properties of these composites and explore their efficacy against E. coli and S. aureus, two common bacterial pathogens. The composites are prepared using eco-friendly and conventional methods to ensure effective nanoparticle attachment to the GO surface. Structural and morphological characteristics are confirmed through SEM, AFM, EDS, XRD, UV-vis, FTIR, and Raman spectroscopy. The antibacterial efficacy of the composites is tested through disk diffusion assays, colony-forming unit (CFU) counts, and turbidimetry analysis, with an emphasis on understanding the effects of different nanoparticle concentrations. The results demonstrated a dose-dependent antibacterial effect, with GO/AgNP-1 showing superior antibacterial activity over GO/AgNP-2, particularly at lower concentrations (32.0μg/mL and 62.5μg/mL). The GO/CuNP composite also exhibited significant antibacterial properties, with optimal performance at 62.5μg/mL for both bacterial strains. Turbidimetry analysis confirmed the inhibition of bacterial growth, especially at moderate concentrations, although slight nanoparticle aggregation at higher doses reduced efficacy. Lastly, both GO/AgNP and GO/CuNP composites demonstrated significant antibacterial potential. The results emphasize the need to fine-tune nanoparticle concentration and refine synthesis techniques to improve their efficacy, positioning these composites as strong contenders for antimicrobial use.

A study on bacterial inactivation using green synthesized photocatalytically active TiO2, MgO, TiO2/MgO nanoparticles

Madhuca longifolia (Mahua) flower extracts were utilised to perform the green synthesis of titanium dioxide (TiO2), magnesium oxide (MgO) nanoparticles, and a nanocomposite consisting of TiO2/MgO. Mahua flower extracts were used as both reducing and capping agents in a sol-gel synthesis method. The effectiveness of the green reducing agent in improving the surface structure of the green nanoparticles was demonstrated. FTIR, XRD, FESEM, and UV vis spectroscopy were employed to analyse the successful synthesis of TiO2, MgO, and TiO2/MgO nanocomposites. A study was done to examine the process of employing these nanoparticles to deactivate Escherichia coli (E. coli) by photocatalysis. The effectiveness of these nanoparticles in inhibiting the growth of the bacterial species was demonstrated. The optimisation of the bacterial inactivation experiment was performed using Design Expert's RSM CCD model on all three nanoparticle samples. The optimisation study investigated the impact of nanoparticle concentration and exposure duration on the inhibition of bacterial growth. The highest levels of percent inhibition (%I) were recorded as 85.4 % for TiO2/MgO, 82.8 % for TiO2, and 65.14 % for MgO at a concentration of 50 mg/2 ml and an exposure time of 2 h. The effectiveness of these nanoparticles in exhibiting inhibition has been limited, indicating their prospective use in the advancement of antimicrobial coatings and other applications, such as disinfectants, in the future.

Photosensitizer conjugated carbon dots@dopamine-copper sulfide nanocomposites: Advanced photoactive agents for antibacterial applications through experimental and theoretical insights

The massive use and abuse of antibiotics has given birth to drug-resistant bacteria and emergence of severe bacterial infections in people. Intriguingly, light activated antimicrobial activity i.e. antimicrobial photodynamic therapy has gained enhanced therapeutic potential and efficacy in killing the bacterial cells. Therefore, the present study investigates the efficacy of employing advanced nanocomposites for biocidal inhibition of bacterial growth through enhanced sterilization capabilities. Specifically, dopamine functionalized CuS NPs combined with carbon dots (CDs@Dop-CuS) were selected for their remarkable photodynamic potential when used in conjunction with methylene blue (MB). Comparative and synergistic application of Dop-CuS, CDs, and MB revealed the superior singlet oxygen generation potency of MB/CDs@Dop-CuS. Furthermore, the structural changes in the E. coli bacterial cells membrane were elucidated through scanning electron microscopy imaging, demonstrating superior inhibition rates of MB/CDs@Dop-CuS compared to MB alone under 660 nm irradiation. The commendable docking score and binding potential of CDs@Dop-CuS nanocomposites obtained via molecular docking simulations further validate their efficacy as photosensitizers against E. coli bacterial cells. Thus, this novel MB/CDs@Dop-CuS photosensitizer provides enhanced efficacy as an alternative to traditional antibiotic treatments, offering a superior disinfection for public utility services and addressing the growing issue of drug-resistant bacterial infections.

Redox reaction of a RuIII(pic)3 complex with cysteine: Spectral, kinetic and biological studies

The kinetics of the reduction of [RuIII(pic)3] (pic− = picolinate) with cysteine leading to the formation of the corresponding red coloured [RuII(pic)3]− complex (λmax = 466 nm, εmax = 12000 M−1 cm−1) was studied by using stopped-flow and rapid scan spectrophotometry. The time course of the reaction was followed at 466 nm as a function of cysteine concentration, pH and temperature. Kinetic data (k = 291 ± 4 M−1 s−1 at 25 °C and pH 8.4) and activation parameters (ΔH≠ = 36 ± 1 kJ mol−1 and ΔS≠ = −78 ± 3 J mol−1 deg−1) are interpreted in terms of a mechanism involving rate-determining outer-sphere electron transfer between Ru(III) and the cysteine. Inhibition of bacterial growth (Klebsiella pneumonia and Staphylococcus aureus) by the [RuIII(pic)3] complex both in absence and presence of cysteine has been examined, and the results show a positive effect of cysteine addition on the anti-bacterial activity of the complex for S.aureus.

Diastereomeric pure pyrazolyl-indolyl dihydrofurans: Unveiling isomeric selectivity in antibacterial action via in vitro and in silico insights

Developing pure diastereoisomeric molecular hybrids for the selective inhibition of bacterial growth opened new avenues for combating the ever-increasing microbial resistance. Considering this, a series of diastereoisomeric pure pyrazolyl-dihydrofurans (7a-7y) were synthesized and characterized using NMR, LCMS, and X-ray crystallography. DFT based method was used to explore the configurational stability of cis over trans isomeric form. Considering 7a and 8a as representative isomeric forms with same structural framework, the difference in their bio-efficacy against bacterial and fungal strains was assessed using serial dilution method. The relatively high inhibition of bacterial growth by the cis isomeric form (7a) (MIC = 1.562 µg/mL), amoxicillin (MIC = 3.125 µg/mL) inspired us to broaden the substrate scope for synthesizing a series of pure diastereoisomeric cis forms as selective anti-bacterial agents. However, both the isomers displayed antifungal activity less than the standard drug (Fluconazole) employed in the study. All the reactions proceeded smoothly and yielded a diverse array of dihydrofuran derivatives. The developed synthetics were found to be non-cytotoxic against mouse fibroblast cells and didn’t affect the seed germination of Brassica nigra seeds when treated at a concentration of 1 mg/mL. The experimentally determined in vitro results were further validated using in silico molecular docking and dynamics studies.

Exploring Myrrh Oil as a Natural Antimicrobial Agent Against Oral Pathogens: An In Vitro Research

Background: While contemporary pharmaceuticals play a critical role in managing oral infections, there remain persistent concerns regarding their chemical composition and potential adverse effects. This apprehension has led to an increased focus on exploring natural alternatives, particularly herbal substances, for their potential therapeutic benefits in oral health. Aim: This study aimed to examine the antibacterial properties of myrrh oil against common oral bacteria, including Candida, Escherichia coli, Klebsiella, and Staphylococcus aureus, and to assess its suitability as a natural alternative in oral healthcare. Methods: Oral swabs were obtained from 50 individuals from various socioeconomic backgrounds. The isolated organisms were cultivated on different types of media and identified using established microbiological methods. Bacterial growth inhibition was evaluated by culturing subsequent cultures on Muller-Hinton agar with myrrh oil. This agar medium was selected for its suitability in evaluating myrrh oil’s suppressive impact on oral bacteria proliferation. Results: Candida demonstrated abundant proliferation on the control media but showed a reduction in colony-forming units when treated with myrrh oil. E. coli, Klebsiella, and Staphylococcus aureus exhibited decreased growth and suppressed colony formation when exposed to myrrh oil. Conclusion: These findings indicate that myrrh oil can prevent the growth of oral bacteria, making it a promising natural antibacterial agent for managing oral health. Additional investigations are needed to examine the safety, ideal dosage, and clinical feasibility of this treatment.

Co-selective effect of dissolved organic matter and chlorine on the bacterial community and their antibiotic resistance in biofilm of drinking water distribution pipes

The proliferation of pathogenic bacteria and antibiotic resistance genes (ARGs) in the biofilm of drinking water distribution pipes poses a serious threat to human health. This work adopted 15 polyethylene (PE) pipes to study the co-selective effect of dissolved organic matter (DOM) and chlorine on the bacterial community and their antibiotic resistance in biofilm. The results indicated that ozone and granular activated carbon (O3-GAC) filtration effectively removed lignins and proteins from DOM, and chlorine disinfection eliminated carbohydrate and unsaturated hydrocarbons, which both contributed to the inhibition of bacterial growth and biofilm formation. After O3-GAC and disinfection treatment, Porphyrobacter, unclassified_d_bacteria, and Sphingopyxis dominated in the biofilm bacterial community. Correspondingly, the bacterial metabolism pathways, including the phosphotransferase system, phenylalanine, tyrosine and tryptophan biosynthesis, ABC transporters, and starch and sucrose metabolism, were downregulated significantly (p < 0.05), compared to the sand filtration treatment. Under such a situation, extracellular polymeric substances (EPS) secretion was inhibited in biofilm after O3-GAC and disinfection treatment, postponing the interaction between EPS protein and pipe surface, preventing bacteria, especially pathogens, from adhering to the pipe surface to form biofilm, and restraining the spread of ARGs. This study revealed the effects of various water filtration and disinfection processes on bacterial growth, metabolism, and biofilm formation on a molecular level, and validated that the O3-GAC filtration followed by chlorine disinfection is an effective and promising pathway to control the microbial risk of drinking water.

Examining Metal Complexes Formed from New Schiff Base ‎Ligand ‎Derived from Benzene Carbaldehyde: Evaluation of Anti-‎biofilm and ‎Anti-bacterial Properties

One of the most difficult tasks in modern medical societies is the process of identifying a cure for many infectious diseases caused by drug-resistant microbes. Therefore, it has become necessary to discover new compounds that work in this regard. The currently prepared Schiff base, derived from thiazole, has a biological activity against bacteria and biofilms and its activity increases when it is associated with copper, zinc and platinum ions and forms metal complexes. This study highlights the synthesis and evaluation of novel biological compounds as inhibitors of bacterial growth and biofilms. A three newly complexes are resulting from the reaction of a new Schiff base ligand (LC) with metal ions (Zn, Cu, Pt). The new ligand (LC) was prepared from the reaction of precursor (P) and benzenecarbaldehyde. The prepared compounds were characterized by 1H&amp;13CNMR, FTIR, UV-Vis, Magnetic susceptibility, CHNS and Molar conductivity. It was determined that the anti-bacterial activity of the newly synthesized Lc and (Cu-Lc) was mightily significant towards more antibiotic-resistant bacteria and had low (MIC) values. Like that, anti-biofilm inhibitory of the same compounds showed 100% of clinical isolates of P. aeruginosa and S. aureus in 16 and 32 mg/ml respectively, whereas (Zn-Lc) were inhibited 100% in 4 mg/ml. On the other hand (Pt-Lc) inhibited 100 % in 2 mg/ ml. Good yield was obtained from the synthesis of new compounds from the starting material. They can be potential candidates as inhibitors of bacteria and biofilms.

Testing the Inhibitory Activity of Bajakah Tampala (Spatholobus littoralis Hassk) Wood Extract from South Kalimantan on the Growth of Pseudomonas aeruginosa Bacteria

Background: Dental root canal treatment aims to eliminate microorganisms that cause infection in the tooth root canal, one of which is Pseudomonas aeruginosa bacteria. Disinfection of dental root canals with 0.5% - 5.25% NaOCl irrigation solution is still constrained so it is necessary to look for alternatives. The bajakah tampala plant (Spatholubus littoralis Hassk) is known to contain antibacterial compounds, namely flavonoids, saponins, tannins, and polyphenols. Objective: To evaluate the inhibitory activity of bajakah tampala wood extract (Spatholobus littoralis Hassk) from South Kalimantan against the growth of Pseudomonas aeruginosa bacteria. Method: Post test-only with control group design. The test groups were 100%, 75%, 50% bajakah tampala wood extract solution and positive control 2.5% NaOCL solution. Extraction using maceration method. Bacterial growth inhibition was tested by well diffusion method. Inhibition zone was measured using a caliper. Results: The growth inhibition from the largest to the smallest was shown by 75%, 100% and 50% bajakah wood extracts with mean inhibition zone diameters of 5.05 mm, 3.84 mm and 2.02 mm respectively, meanwhile the positive control was 16.14 mm. One Way Anova test showed significant difference in inhibition (p&lt;0.05) in all groups. Post hoc test showed no significant difference in the inhibition of 75% bajakah tampala wood extract with 100% extract. The inhibition of 100% and 75% extracts was significantly greater than 50% extract. The inhibition of NaOCL 2.5% was significantly greater than all groups of test extracts. Conclusion: Bajakah tampala wood extract has inhibitory activity against the growth of Pseudomonas aeruginosa bacteria.

Antibacterial Biocomposite Based on Chitosan/Pluronic/Agarose Noncovalent Hydrogel: Controlled Drug Delivery by Alginate/Tetracycline Beads System.

Designing a wound dressing with controlled uptake, antibacterial, and proper biocompatibility is crucial for the appropriate wound healing process. In this study, alginate/tetracycline (Alg/TC) beads were produced and embedded into chitosan/pluronic/agarose semi-interpenetrating polymer network hydrogel, which serves as a potential biocompatible dressing for treating skin wounds. The effect of pluronic content on the porosity, swelling, mechanical characteristics, and degradation of the hydrogel was investigated. Furthermore, the impact of Alg beads on TC release was subsequently examined. In the absence of Alg beads, faster release was observed. However, after incorporating beads into the hydrogels, the release was sustained. Particularly, the hydrogel containing Alg beads exhibited a nearly linear release, reaching 74% after 2 days in acidic media. The antimicrobial activity and biocompatibility of the hydrogel were also evaluated to assess the capability of the TC-loaded hydrogels for wound dressing applications. The hydrogel demonstrated efficient antibacterial features against Gram-positive and Gram-negative bacteria. Additionally, the sample behavior was evaluated against exposure to yeast. Furthermore, based on biocompatibility studies using HFF2 cells, the TC-loaded hydrogel exhibited remarkable biocompatibility. Overall, this novel composite hydrogel shows remarkable biocompatibility and antibacterial activities which can be used as a great potential wound dressing to prevent wound infections due to its effective inhibition of bacterial growth.

Enhancing Antibiotic Efficacy with Natural Compounds: Synergistic Activity of Tannic Acid and Nerol with Commercial Antibiotics against Pathogenic Bacteria

The search for synergies between natural products and commercial antibiotics is a promising strategy against bacterial resistance. This study determined the antimicrobial capacity of Nerol (NE) and Tannic Acid (TA) against 14 pathogenic bacteria, including ESKAPE pathogens. TA exhibited the lowest Minimum Inhibitory Concentrations (MICs) at 162.5 µg/mL against Pasteurella aerogenes and 187.5 µg/mL against Acinetobacter baumannii (WHO priority 1). NE showed its lowest MIC of 500 µg/mL against both Pasteurella aerogenes and Salmonella enterica. A total of 35 combinations of NE and 13 of TA with eight commercial antibiotics were analyzed. For NE, combinations with Streptomycin and Gentamicin were effective against Salmonella enterica, Bacillus subtilis, and Streptococcus agalactiae, with antibiotic MIC reductions between 75.0 and 87.5%. TA showed six synergies with Chloramphenicol, Ampicillin, Erythromycin, and Streptomycin against Acinetobacter baumannii, Streptococcus agalactiae, and Pasteurella aerogenes, with MIC reductions between 75.0 and 93.7%. Additionally, 31 additive effects with antibiotics for NE and 8 for TA were found. Kinetic studies on these synergies showed complete inhibition of bacterial growth, suggesting that natural products enhance antibiotics by facilitating their access to targets or preventing resistance. Given their safety profiles recognized by the EPA and FDA, these natural products could be promising candidates as antibiotic enhancers.

Exploring Antimicrobial Potency, ADMET, and Optimal Drug Target of a Non-ribosomal Peptide Sevadicin from Bacillus pumilus, through In Vitro Assay and Molecular Dynamics Simulation.

The current study was designed to explore the biosynthetic potential of sevadicin in Bacillus pumilus species and its interaction with bacterial drug target molecules. The non-ribosomal peptide (NRP) cluster in B. pumilus SF-4 was preliminarily confirmed using PCR-based screening, and the bioactivity of strain SF-4 culture extract was assessed against a set of human pathogenic strains. The susceptibility assay showed that strain SF-4 extract had higher inhibitory concentrations (312-375µg/mL) than ciprofloxacin. Genome mining of B. pumilus strains (n = 22) using AntiSMASH and BAGEL identified sevadicin coding biosynthetic gene cluster only in strain SF-4, constitutes of two core biosynthetic genes, three additional biosynthetic genes, two transport-related genes, and one regulatory gene. The molecular docking of sevadicin with various putative bacterial drug targets such as dihydropteroate, muramyl ligase E, topoisomerase, penicillin-binding protein, and in vitro safety analyses were conducted with detailed ADMET screening. The results showed that sevadicin makes hydrophobic interaction with MurE (PDB ID: 1E8C and 4C13) via hydrogen bonding, suggesting bacterial growth inhibition by disrupting the cell wall synthesis pathway and exhibiting a secure biosafety profile. The stability and compactness of sevadicin/MurE complexes were assessed via molecular dynamic simulation using RMSD, RMSF, and Rg. The simulation results revealed the binding stability of sevadicin/MurE complexes and indicated that the complexes can't be easily deformed. In conclusion, the current study explored the biosynthesis of sevadicin in B. pumilus for the first time and found that sevadicin inhibits bacterial growth by inhibiting cell wall synthesis via targeting the MurE enzyme and exhibits no toxicity.

Comparison between Green and Chemical Synthesis of Silver Nanoparticles: Characterization and Antibacterial Activit

Using chemical reduction and green technology, two different approaches are used in the current work to synthesize silver nanoparticles. Pomegranate peel extract has been utilized in green technology applications. Furthermore, In the chemical approach, polyvinylpyrrolidine and ascorbic acid were utilized as reducing agents, and the optical, structural, and antibacterial characteristics of the two versions were investigated. In comparison to the chemical reduction variant (30.38 nm), the particle sizes in the green technique (19.5 nm) were smaller. Comparing green silver nanoparticles to chemically synthesized silver nanoparticles, SEM pictures showed that the former had formed a distinct crystalline shape and were evenly distributed on the surface. Granules constituted the shape of the particles. Additionally, it spreads topically. Whereas the greenly synthesized variant's absorption band was at 280 nm, the chemically synthesized variant's absorption band was at 300 nm. It was demonstrated by spectroscopic data of green silver nanoparticles that they have the capacity to produce and stabilize silver nanoparticles. Chemically produced green silver nanoparticles were also exposed to FTIR analysis to identify active functional groups. Silver particles can also be stabilized by chemically produced silver nanoparticles. To assess the antibacterial activity, the nanoparticle agar diffusion method was employed. The bacteria detected in the medium were Staphylococcus aureus and Escherichia coli. In the green form, the bacterial growth inhibition zone was larger and was produced with varying concentrations of 25 ml, 50 ml, 75 ml, and 100 ml, or 13 ml, 10 ml, 9 ml, and 8 ml for Staphylococcus aureus and 15 ml, 12 ml, 10 ml, and 7 ml for E. coli, respectively. Green-produced transcripts exhibited higher antibacterial responses, which were likely caused by the faster rate of nanoparticle stabilization mechanism by organic compounds found in pomegranate fruit peel extract.

Antioxidant dimension and potential as bacterial growth inhibitors in crude extracts of two Artemisia species (Artemisia indica Willd. and Artemisia maritima L.) from Gilgit-Baltistan region, Pakistan

Antioxidant dimension and potential as bacterial growth inhibitors in crude extracts of two Artemisia species (Artemisia indica Willd. and Artemisia maritima L.) from Gilgit-Baltistan region, Pakistan