Antimicrobial Behavior Research Articles

Microbial landscapes in Trinervitermes trinervoides termite colonies are affected by mound compartments and soil properties but not by symbiotic Podaxis fungi

Termites are important ecosystem engineers and play key roles in modulating microbial communities within and outside their mounds. Microbial diversity within termite mounds is generally lower than surrounding soils, due to termite-associated antimicrobial compounds and active sanitary behaviours. Microbial symbionts of termites can also influence the microbial landscape, by inhibiting or out-competing other microbes. Certain members of the arid habitat fungal genus Podaxis (Agaricomycetes; Agaricaceae) are symbiotic with savannah specialist grass-cutting termites, with the potential to influence mound-associated microbiomes. To test this, we characterized fungal (ITS2) and bacterial (16S rRNA) communities within and outside 49 Trinervitermes trinervoides mounds with and without Podaxis fruiting bodies across a 1000 km transect in South Africa. We predicted that Podaxis would be a dominant member of the fungal communities in mounds and negatively impact microbial diversity. Further, we explored how environmental variables shaped microbial communities, including whether soil elemental composition affected Podaxis presence. As expected, we observed less diverse fungal communities, but not bacterial communities, within than outside mounds, while microbial communities differed by sampling regions and mound compartments. Podaxis sequences were present in 48 out of 49 mounds in low relative abundances, and neither fruiting body presence nor sequence abundance were associated with microbial community diversity or composition. There was, however, an overall association between the presence of Podaxis fruiting bodies and elemental composition, with different elements displaying varying associations depending on geographic region. Both environmental variables and soil elements associated with fungal and bacterial taxa, indicating that they are key drivers of microbial community composition. Taken together, our findings suggest that microbial landscapes in termite mounds are not strongly influenced by Podaxis but mainly driven by termite filtering and regional abiotic variables and elemental compositions.

Development of Scaffolds with Chitosan Magnetically Activated with Cobalt Nanoferrite: A Study on Physical-Chemical, Mechanical, Cytotoxic and Antimicrobial Behavior.

Background/Objectives: This study investigates the development of 3D chitosan-x-cobalt ferrite scaffolds (x = 5, 7.5, and 10 wt%) with interconnected porosity for potential biomedical applications. The objective was to evaluate the effects of magnetic particle incorporation on the scaffolds' structural, mechanical, magnetic, and biological properties, specifically focusing on their biocompatibility and antimicrobial performance. Methods: Scaffolds were synthesized using freeze-drying, while cobalt ferrite nanoparticles were produced via a pilot-scale combustion reaction. The scaffolds were characterized for their physical and chemical properties, including porosity, swelling, and mechanical strength. Hydrophilicity was assessed through contact angle measurements. Antimicrobial efficacy was evaluated using time kill kinetics and agar diffusion assays, and biocompatibility was confirmed through cytotoxicity tests. Results: The incorporation of cobalt ferrite increased magnetic responsiveness, altered porosity profiles, and influenced swelling, biodegradation, and compressive strength, with a maximum value of 87 kPa at 7.5 wt% ferrite content. The scaffolds maintained non-toxicity and demonstrated bactericidal activity. The optimal concentration for achieving a balance between structural integrity and biological performance was found at 7.5 wt% cobalt ferrite. Conclusions: These findings suggest that magnetic chitosan-cobalt ferrite scaffolds possess significant potential for use in biomedical applications, including tissue regeneration and advanced healing therapies. The incorporation of magnetic properties enhances both the structural and biological functionalities, presenting promising opportunities for innovative therapeutic approaches in reconstructive procedures.

Melt-Processed Polybutylene-Succinate Biocomposites with Chitosan: Development and Characterization of Rheological, Thermal, Mechanical and Antimicrobial Properties.

The current research is devoted to the development and characterization of green antimicrobial polymer biocomposites for food packaging applications. The biocomposites were developed by melt compounding on the basis of two different succinate polymer matrices with varying chain stiffness-polybutylene succinate (PBS) or its copolymer with 20 mol.% of polybutylene adipate (PBSA). Fungi chitosan oligosaccharide (C98) and crustacean chitosan (C95) were used as antimicrobial additives. The rheological properties of the developed biocomposites were determined to clear out the most suitable temperature for melt processing. In addition, mechanical, thermal, barrier and antimicrobial properties of the developed biocomposites were determined. The results of the investigation revealed that PBSA composites with 7 wt% and 10 wt% of the C98 additive were more suitable for the development of green packaging films because of their higher ultimate elongation values, better damping properties as well as their superior anti-microbial behavior. However, due to the lower thermal stability of the C98 additive as well as PBSA, the melt processing temperatures of the composites desirably should not exceed 120 °C. Additionally, by considering decreased moisture vapor barrier properties, it is recommended to perform further modifications of the PBSA-C98 composites through an addition of a nanoclay additive due to its excellent barrier properties and thermal stability.

Preparation and Characterization of Anti-Microbial Wound Healing Materials from Natural Origins

Abstract Many types of polymers utilized as wound dressings, Polycaprolactone (PCL) displays high degree of biocompatibility as well as biodegradability, the mechanical strength states PCL in the foreground materials used in wound healing therapies. Current work aims to develop new types of wound plaster dressing, a multiple of natural and medical materials (aloe Vera, calendula and phenobarbital) were used to enhance the anti-microbial behavior as well as pain removal during wound healing period. Aloe Vera gels, Calendula extraction, with phenobarbital drug were precipitates on PCL layer in different percentage. Microstructure observation proves that polycaprolactone polymer is good base material supports dressing constituents, wound dressing homogeneity increased due to chemical reactions between the Aloe Vera and other materials. the main elements of dressing (carbon and oxygen) observed from chemical analysis (EDS) which is also showed that using combination of natural plants (aloe vera and Calendula) with phenobarbital medicine create wound plaster layer with wide range of active elements lead to therapeutic effects including antibacterial, In (FTIR) the results show using mixture of natural additives (aloe, calendula), medicine like phenobarbital in PCL lead to create wound plaster with high (OH) content acts to expedite the skin’s healing process by maintaining the natural level of minerals and hydration at wound area. Hydrophobicity of wound can minimized when adding some hydrophilic materials like Aloe Vera, phenobarbital and calendula, Aloe Vera gel, phenobarbital, as well as calendula decrease the contact angle value. Providing high adhesion between wound plaster and skin tissue. All prepared wound plaster has same and high resistance to Staphylococcus bacteria (40mm).

Quantitative study of early-stage transient bacterial adhesion to bioactive glass and glass ceramics: atomic force microscopic observations

Antimicrobial potential of bioactive glass (BAG) makes it promising for implant applications, specifically overcoming the toxicity concerns associated with traditional antibacterial nanoparticles. The 58S composition of BAG (with high Ca and absence of Na) has been known to exhibit excellent bioactivity and antibacterial behaviour, but the mechanisms behind have not been investigated in detail. In this pioneering study, we are using Atomic Force Microscopy (AFM) to gain insights into 58S BAG’s adhesive interactions with planktonic cells of both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria; along with the impact of crystallinity on antibacterial properties. We have recorded greater bacterial inhibition by amorphous BAG compared to semi-crystalline glass–ceramics and stronger effect against gram-negative bacteria via conventional long-term antibacterial tests. AFM force distance curves has illustrated substantial bonding between bacteria and BAG within the initial one second (observed at a gap of 250 ms) of contact, with multiple binding events. Further, stronger adhesion of BAG with E.coli (~ 6 nN) compared to S. aureus (~ 3 nN) has been found which can be attributed to more adhesive nano-domains (size effect) distributed uniformly on E.coli surface. This study has revealed direct evidence of impact of contact time and 58S BAG’s crystalline phase on bacterial adhesion and antimicrobial behaviour. Current study has successfully demonstrated the mode and mechanisms of initial bacterial adhesion with 58S BAG. The outcome can pave the way towards improving the designing of implant surfaces for a range of biomedical applications.

Staphylococcus aureus major cell division protein FtsZ assembly is inhibited by silibinin, a natural flavonolignan that also blocked bacterial growth and biofilm formation

The bacterial cell division protein FtsZ has been considered a potential therapeutic target due to its rapid treadmilling that induces cellular wall construction in bacteria. The current study discovered a novel antimicrobial compound, silibinin, a natural flavonolignan and its impact on the recombinant S. aureus FtsZ (SaFtsZ). Silibinin inhibited S. aureus Newman growth in a dose-dependent manner. The IC50 and MIC values for silibinin were 75 μM and 200 μM, respectively. It had no cytotoxicity against HEK293 cells in vitro. Silibinin also enlarged the bacterial cell morphology by ∼40 folds and showed antibiofilm property. It perturbed the S. aureus membrane potential both at IC50 conc. and at MIC conc. Further, it inhibited both the polymerization and GTPase activity of SaFtsZ. It did not inhibit tubulin assembly, a eukaryotic FtsZ homolog. A fluorescence quenching study yielded the Kd value for SaFtsZ-Silibinin interaction and binding stoichiometry 0.857 ± 0.188 μM and 1:1, respectively. Both in silico study and competition assay indicated that silibinin binds at the GTP binding site on SaFtsZ. The Ki value for the silibinin-mediated inhibition of SaFtsZ was 8.8 μM. Therefore, these findings have comprehensively shown the antimicrobial behavior of silibinin on S. aureus Newman cells targeting SaFtsZ.

Mussel shell-derived biogenic hydroxyapatite as reinforcement on chitosan-loaded gentamicin composite for antibacterial activity and bone regeneration

In this study, hydroxyapatite (HAp) was synthesized from natural biowaste materials, specifically mussel shells, and combined with chitosan (CS) and gentamicin sulfate antibiotic (GA) using an in-situ method. The resulting composite material, designated HAp/CS-GA, has its physicochemical and structural properties characterized by Fourier transform infrared spectroscopy (FTIR) analysis. The structure was confirmed by X-ray diffraction (XRD) analysis. Additionally, field emission scanning electron microscopy (FE-SEM) equipped with the energy dispersive X-ray spectroscopic (EDX) technique was used to determine the surface topography and main components. The composite of HAp/CS-GA was analyzed using a drug release profile by UV–visible spectroscopy (UV–Vis). The fabricated composites antimicrobial behavior was examined against bone infection-causing Gram-positive and Gram-negative bacteria, showing potential activity against Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus compared to Escherichia coli, respectively. Simultaneously, the cytotoxicity of the composite was evaluated by MTT assay using an MG-63 osteoblast-like cell line that exhibited no toxicity in the prepared composite. After a 24 h incubation period, the MG-63 cells on the HAp/CS-GA composite showed good proliferation, according to Hoechst 33258 fluorescence staining results. The results suggested that the composite had excellent biocompatibility and antibacterial activity and enhanced the osteoblast cell proliferation. Therefore, the designed HAp/CS-GA composite would be a promising candidate for bone tissue engineering.

From Synthesis to Functionality: Tailored Ionic Liquid-Based Electrospun Fibers with Superior Antimicrobial Properties.

Herein, we report an efficient and facile strategy for the preparation of imidazolium-based ionic liquid (IL) monomers ([CnVIm][Br], n = 2, 4, 6, 8, 10, and 12) and their corresponding polymeric ionic liquids (PILs) with potent antimicrobial activities against Gram-negative and Gram-positive bacteria and fungi. The electrospinning technique was utilized to tailor the polymers with the highest antimicrobial potency into porous membranes that can be easily implemented into diverse systems and extend their practical bactericidal application. The antimicrobial mechanism of obtained ILs, polymers, and nanomaterials is considered concerning the bearing chain length, polymerization process, and applied processing technique that provides a unique fibrous structure. The structure composition was selected due to the well-established inherent amphiphilicity that 1-alkylimidazolium ILs possess, coupled with proven antimicrobial, antiseptic, and antifungal behavior. The customizable nature of ILs and PILs complemented with electrospinning is exploited for the development of innovative antimicrobial performances born from the intrinsic polymer itself, offering solutions to the increasing challenge of bacterial resistance. This study opens up new prospects toward designer membranes providing a complete route in their designing and revolutionizing the approach of fabricating multi-functional systems with tunable physicochemical, surface properties, and interesting morphology.

Innovative bis-dihydrazothiazolone derivatives with a 1,4-xylenyl spacer: Design, antimicrobial prospective and construction of several transition metal chelates with iron, cobalt and zinc

Several new xylenyl-spaced bis-dihydrazothiazoles 6a-e and bis-dihydrazothiazolones 9a-e were synthesized by the simple reaction between bis-thiosemicarbazone 3 as a common synthetic scaffold, with two series of hydrazonoyl halides derivatives 4a-e and 7a-d. The chelation ability of these novel bis-dihydrazothiazole derivatives to perform as neutral tridentate ligands and coordinate to transition metal ions; Fe(III), Co(II), or Zn(II) through azomethine-N, thiazole-S, and azo-N atoms to form metal complexes with a metal/ligand ratio of 2:1 was elucidated. Diffused reflectance, magnetic moment, 1HNMR, FT-IR, TGA, and molar conductivity, were used to interpret the structures of all new xylenyl-spaced bis-heterocyclic compounds and their metal chelates. In-vitro, antibacterial and antiviral screening of these innovative xylenyl-spaced bis-dihydrazothiazole derivatives, as well as a selected group of their transition metal chelate complexes [M2L], were inspected, and the data was evaluated in comparison to those of Ketoconazole and Gentamycin as antimicrobial control standards using the agar well diffusion assay protocol against a selected group of fungal and bacterial species. Several compounds displayed respectable to great antimicrobial behavior against the examined microbial species. Bis-dihydrazothiazole 6c, particularly, showed exceptional inhibition of both C. albicans and E. coli. However, bis-dihydrazothiazolone 9b showed excellent inhibition of A. fumigatus. Additionally, amongst the three synthesized metal complexes [M2L], only the zinc complex, [Zn2L] showed remarkable inhibition of both C. albicans and S. typhimurium and was even more potent than the free ligand, 9a itself.

Antimicrobial Use Rates by Patient Care Units using NHSN Antimicrobial Use Option in TN Reporting Facilities, 2015–2023

Background: Tracking antimicrobial use (AU) is a Core Element of Hospital Antimicrobial Stewardship Programs and important to help curb the public health threat of antimicrobial resistance. The National Healthcare Safety Network’s (NHSN) AU Option serves as a way for facilities, healthcare systems, and health departments to track and report AU rates within their jurisdictions. Many analyses at the state and national levels do not assess unit-level AU rates. This study investigates AU rates among patient care units in Tennessee reporting facilities from 2015 to 2023 and the most frequently used antimicrobial agents based on AU rates within select unit types. Methods: A retrospective analysis was conducted utilizing data obtained from the NHSN AU Option for inpatient units in Tennessee acute care hospitals. Units were defined as critical care (including neonatal), ward, oncology ward, stepdown, operating room (OR), and mixed acuity and specialty care areas, termed ‘other’. Unit types with fewer than five facilities represented were excluded. AU rates were determined by Antimicrobial Days of Therapy (DOT) per 1000 Days Present (DP). Statistical analyses , including descriptive statistics and comparison among the units by ANOVA test , were calculated using SAS Version 9.4. Results: Eighty-three facilities reported at least one month of data into the NHSN AU Option between 2015–2023. Among 70 facilities reporting inpatient units, the highest AU rate was observed in oncology ward units (n=12, 1114.6 DOT/1000 DP). A significant difference in AU rates was observed between oncology ward units compared to different unit types (p < 0 .001). Vancomycin, ceftriaxone, and piperacillin/tazobactam were the most used antimicrobials with AU rates of 83, 76, and 65 DOT/1000 DP, respectively. Vancomycin AU rates were significantly higher in oncology ward units compared to stepdown, ward, other, and OR units (p < 0 .0001). Ceftriaxone AU rate was significantly higher in stepdown units compared to oncology ward, other, and OR units (p < 0 .0001). Piperacillin/tazobactam AU rate was significantly higher in critical care units compared to different unit types (p < 0 .0001). Conclusion: During the study period, the AU rate varied across hospital inpatient units in Tennessee, with the highest AU rate in oncology wards. This unit-specific approach is critical to address the diverse antimicrobial prescribing behaviors observed, indicating that interventions should be customized to each unit’s distinct antimicrobial usage patterns for successful stewardship efforts. Targeted strategies focused on individual wards rather than facility-wide initiatives appear essential for effective reduction in antibiotic usage.

In vitro and in silico approach towards antimicrobial and antioxidant behaviour of water-soluble chitosan dialdehyde biopolymers

Chitosan dialdehyde (ChDA) was prepared from a three-step process initiated by thermal organic acid hydrolysis, periodate oxidization, and precipitation from native chitosan (NCh). The developed ChDA resulted in an aldehydic content of about 82 % with increased solubility (89 %) and maximum yield (97 %). The functional alteration of the aldehydic (-CHO) group in ChDA was established using vibrational stretching at 1744 cm−1. The increase in the zone of inhibition of ChDA compared to NCh has confirmed the inherent antimicrobial effect against bacterial and fungal species. ChDA showed better antioxidant activity of about 97.4 % (DPPH) and 31.1 % (ABTS) compared to NCh, measuring 45.3 % (DPPH) and 15.9 % (ABTS), respectively. The novel insilico predictions of the ChDA's biocidal activity were confirmed through molecular docking studies. The amino acid moiety such as ARG 110 (A), ASN 206 (A), SER 208 (A), THR 117 (B), ASN 118 (B), and LYS 198 (B) residues of 7B53 peptide from E. coli represents the binding pockets responsible for interaction with aldehyde group of ChDA. Whereas PHE 115 (E), ALA 127 (H), TYR 119 (C), GLN 125 (H), ASN 175 (E), ARG 116 (E), LYS 101 (H), and LYS 129 (H) of 1IYL A peptide from Candida albicans makes possible for binding with ChDA. Hence, the synergistic effect of ChDA as a biocidal compound is found to be plausible in the drug delivery system for therapeutic applications.

Electrophoretic deposition of TiO2 nanotubes and antibiotics on polyurethane coated stainless steel for improved antibacterial response and cell viability

In the quest for advancing the performance of metallic implants, surface modification emerges as a pivotal strategy to mitigate ion depletion, enhance the host's biological response, and exhibit anti-microbial behavior with reduced cytotoxicity. In this study, we developed a non-traditional electrophoretic deposition (EPD) hybrid coating for medical-grade stainless steel 316 L (SS316L) surfaces covered with a segmented polyurethane (SPU). These coatings are composed of anatase TiO2 nanotubes (TiO2_A), and antibiotics (nisin N or gentamicin G). We characterized the modified metals using FTIR and Raman spectroscopy, contact angle measurements, AFM, TGA, SEM-EDX, as well as assessing their antimicrobial response and cell cytotoxicity. The results demonstrate the formation of porous surfaces with embedded nanotubes and antibiotics within and on the polyurethane surfaces. Samples with SPU+ TiO2_AG EPD exhibited superior coverage, antimicrobial properties, and enhanced viability compared to cases where only particles or antibiotics were coated individually. Additionally, samples of SPU+ TiO2_AN EPD displayed favorable hydrophilicity and suitable cytotoxicity. Therefore, the synergistic effect of nanoparticles and antibiotics positively influences the functionality of the coating.

Self-assembled lyotropic liquid crystals from natural surfactant: A study on their structural, rheological and antimicrobial behaviour

Soft self-assembled systems with smart functions have been explored over the past decades for diverse applications. However, the toxicity of synthetic surfactant based self-assembled systems and their stability always remain a point of concern. There is always a great quest to find an alternative to overcome such shortcomings of self-assembled systems. Hence, in this context, we made an effort to engineer self-assembled lyotropic liquid crystals (LLCs) using different concentrations of the medicinal plant Glycyrrhiza glabra L. in the nonaqueous polar media of glycerol, ethylene glycol and formamide. These nonaqueous solvents with considerable polarity, high cohesive energy, dipole moment and hydrogen bonding ability, not only offer the perfect environment for self-assembly, but also provide longtime stability. Nematic lyotropic ordering is obtained for studied systems at different concentrations of Glycyrrhiza glabra L./ nonaqueous solvents as confirmed via polarising optical microscopy (POM) and X-ray diffraction (XRD) analysis. Electrostatic and hydrogen bonding interactions among polar solvents and amphiphilic Glycyrrhiza glabra L. molecules could be responsible for nematic ordering. FTIR spectroscopy is employed to confirm the hydrogen bonding in LLCs. The prepared LLCs are studied through static, dynamic rheology under the shear range 1–100 s-1 to explore their fluidic behaviour and establish correlation with structural parameters. The studied LLC systems from three solvents exhibit non-Newtonian shear thinning behaviour at all concentrations. The dynamic rheology tests indicate the elastic behaviour of all LLC systems. LLCs derived from glycerol exhibit soft-solid gel-like behaviour, while weak gel-type behaviour is observed for ethylene glycol and formamide-based LLCs. Considering the medicinal value of prepared LLCs, their antibacterial activity has been checked against the gram-positive bacteria Bacillus subtilis. LLC phases show strong antibacterial activity, about 2–3 times better than that of the standard drug streptomycin used for this study.

Synthesis and antimicrobial behaviour of NiO/Ag-based material

The main objective of the present work is the green synthesis of NiO and Ag nanoparticles using the leaf extract of Azadirachta indica and the development of NiO/Ag-based nanocomposites via an ultrasonic process. The synthesised NiO/Ag was characterised using different analytical methods and used as an antimicrobial agent against different bacterial and fungal strains. The antimicrobial study was done using the well diffusion method. The FTIR study indicated the presence of O–H, C–H (methylene or methyl), CO, O–H, and Ni–Ag, Ag–O, or Ni–O bonds on the surface of NiO/Ag. The XRD peaks of NiO/Ag were found to be 31.60 (103), 37.30 (111), 38.10 (111), 43.40 (200), 62.90 (220), 76.50 (008), 77.50 (311), and 79.50 (222), respectively. The maximum zones of inhibition were found to be 21.6 (±0.71), 21.2 (±0.69), 17.9 (±0.39), 13.3 (±0.81), and 12.3 (±0.38) mm against Escherichia coli, Staphylococcus aureus, Salmonella enterica, Candida albicans, and Aspergillus niger after incubation periods. On the basis of these findings, we can conclude that NiO/Ag is a potent antimicrobial agent against a variety of bacterial and fungal species.

Investigating antimicrobial behavior of thymol/Zn encapsulated hierarchically structured zeolite and thymol release kinetics

A new bioactive material was proposed by encapsulating thymol molecules and Zn2+ cations within the post-modified intracrystalline voids of hierarchical zeolite X crystals. To enhance the accessibility of thymol molecules within zeolite X crystals, commercial zeolite samples underwent post-synthesis treatment involving consecutive aqueous KCl, NH4Cl, and Na2H2EDTA solutions. The gas adsorption method utilized the encapsulation of both Zn2+ cation and thymol molecules into the resulting hierarchical zeolite X framework, which demonstrated improved antimicrobial activity. While sole thymol-encapsulated zeolite X exhibited no antimicrobial activity against S. aureus, Zn2+ encapsulated zeolite X (ZnX), thymol encapsulated post-treated zeolite X (HX-thy), and both Zn2+ and thymol encapsulated post-treated zeolite X (ZnHX-thy) displayed zone of inhibition values of 18.7 mm, 25.0 mm, and 37.5 mm, respectively. Adding Zn2+ and creating a hierarchical pore system in the zeolite X framework altered the release profiles. The Higuchi kinetic release model has the highest R2 value to describe the process of thymol release from X-thy, whereas the Elovich release model has the best fitting profile of thymol release kinetics from ZnX-thy, HX-thy, and ZnHX-thy. Results indicate that thymol and Zn2+ containing hierarchical porous materials could be beneficial tools for obtaining enhanced antibacterial activity and stability with reduced degradation and volatility of thymol with extended protection against microbial attack due to the controlled release. These findings highlight an innovative approach to designing sustainable and green materials, utilizing modified porous networks that encapsulate natural antibacterial compounds with environmentally benign metal ions.

The use of small group based educational interventions in General Practice to improve antimicrobial prescribing behaviours: a mixed methods systematic review protocol

Background Inappropriate use of antimicrobial agents in healthcare settings is one area that has received attention as a possible route to mitigate the threat of antimicrobial resistance. Globally, the highest consumption of antimicrobials in human healthcare originates from prescriptions in Primary Care. Strategies to increase appropriate antibiotic prescribing, which can mean not prescribing an antibiotic e.g. cases of viral infection, have been developed and evaluated. This systematic review aims to review the literature of studies of group based in person educational interventions designed to increase appropriate antibiotic prescribing behaviours in General Practice settings. Methods EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, MEDLINE and PsycINFO will be systematically searched from inception until February 2024 for primary studies of group based educational interventions designed to improve the antimicrobial prescribing behaviours in General Practice. Qualitative, quantitative and mixed methods studies that report on the phenomenon of interest will be included. All identified articles will be double screened at title and abstract level. One reviewer will then screen all included studies at full text level, extract the data, code the intervention and perform risk of bias assessment with a second reviewer performing verification of a randomly selected 20% of the articles. We will use an integrated approach to mixed method systematic reviews and will perform a narrative, or if possible quantitative, synthesis. Discussion The review will identify and assess the efficacy and / or effectiveness of small group based educational interventions designed to improve the antibiotic prescribing behaviours of General Practitioners. By using a mixed methods approach we aim to identify the salient content of the included interventions and the perspectives of participants on the content and delivery of the included interventions. We will use the findings to inform the design and content of a small group educational intervention for GP registrars.

Bleomycin‐dependent DNA damage, erythrocyte hemolysis, antitumor MTT assay, and antimicrobial activity studies for Cd (II), Mn (II), Zn (II), Cr (III), and Fe (III) complexes of a multidentate carbohydrazone ligand

Cd (II), Mn (II), Zn (II), Cr (III), and Fe (III) complexes of a carbohydrazone ligand H4EBC, prepared by the reaction of ethyl acetate and carbohydrazide, have been prepared and fully characterized. The ligand H4EBC acted as a bidentate carbohydrazone with Cd (II) and coordinated through the nitrogen of both (‐NH) and (C=N)azomethine groups, while with Mn (II) and Zn (II), it acted as a neutral NN bidentate ligand. In complexes with Fe (III) and Cr (III), H4EBC acts a bi‐negative tetra‐dentate, coordinating through the oxygen atoms of both enolized (C=O)ester groups and the nitrogen of both (C=N)azomethine groups. To illustrate the proposed geometries and chemical reactivity of the compounds, we employed DFT calculations. Additionally, thermal studies provided insights into the stability of the isolated compounds. Interestingly, the prepared complexes demonstrated emission broad bands at various wavelengths, indicating ligand to metal charge transfer. Based on the inhibition of DNA destruction, the complexes can be ranked in the following order: [Cd(H4EBC)Cl2].2H2O] (1) > H4EBC > [Mn(H4EBC)Cl2)].(H2O)2] (2) > [Zn(H4EBC)Cl2].2H2O] (3) > [Fe(H2EBC)Cl(H2O)].H2O (5) > [Cr(H2EBC)Cl (H2O)].H2O (4). Regarding erythrocyte hemolysis, the order of effectiveness can be arranged as follows: (2) > (1) > H4EBC > (5) > (3) > (4). We further investigated the compounds for their potential in antitumor activity against two cell lines and antimicrobial behavior.

Trachyspermum ammi, a plant-based antimicrobial agent for paper packaging in e-commerce for consumer safety

This study used a plant-based antimicrobial agent (Trachyspermum ammi or Ajowan essential oil) to develop a water-based coating emulsion with polyvinyl alcohol as a binder. The emulsion was spray-coated onto the packaging paper to achieve antimicrobial properties and prevent disease transmission during the e-commerce supply chain. The coated papers were studied for their morphological, chemical, mechanical, barrier, and antimicrobial behaviors. The presence of Ajowan oil on coated paper was confirmed by infrared spectroscopy and surface morphology. In parallel, the time-bound release of volatile Ajowan oil from the coated papers was demonstrated when stored in a controlled environment using UV–vis spectroscopy. Both bending stiffness and tear strength significantly increased for coated papers due to the presence of polyvinyl alcohol in the coating, whereas the high concentration of oil resulted slight decrease in tensile and burst strength of coated papers. Finally, the antimicrobial activity of coated paper was checked against S. aureus and E. coli at different concentrations of Ajowan oil in coating and was found to be effective for 10 days. The coated papers also showed remarkable antimicrobial activity when tested against all unknown microbes on bare human hands.

Investigation of antimicrobial potential of nanocomposites based on functionalization of graphene oxide with zinc porphyrin complexes

Herein, zinc porphyrin complexes were synthesised by passing through the formation of free base porphyrin ligands and metalation of free base porphyrins with zinc metal ions. The synthesised zinc porphyrin complexes were functionalised with graphene oxide leading to the formation of zinc porphyrin anchored graphene oxide hybrid nanocomposites. The zinc porphyrins complexes were anchored with graphene oxide through the particular functional group present at the periphery of zinc porphyrins (hydroxyl and carboxyl functional groups in Pr1 and Pr2 respectively). 1H NMR and UV–visible spectroscopic techniques have monitored the successful formation of free base porphyrins and their matching zinc-integrated metalloporphyrin complexes. Various spectroscopic techniques like, photophysical properties (UV–Visible spectroscopy and Fluorescence spectroscopy), Fourier transform infrared (FT-IR), powdered X-ray diffraction (P-XRD) patterns, FE-SEM and EDAX analysis were used to examine the intrinsic characteristics of the prepared nanocomposites. The in-vitro antimicrobial activity of the synthesized complexes and nanocomposites was tested against Staphylococcus aureus gram-positive strain, Klebsiella pneumonia, and Escherichia coli. By working on the antimicrobial behaviour, it has been observed that the compound containing –COOH substitute has shown enhanced antimicrobial activity. The in silico molecular docking studies of the synthesized compounds with the S. aureus nucleoside diphosphate kinase receptor showed strong interactions via hydrogen bonding, π − π interactions and hydrophobic interactions. Molecular dynamics (MDs) simulations were used to study the dynamic behaviour of the complexes as well as nanocomposites which revealed the stability of docked structures with S. aureus nucleoside diphosphate kinase receptor. The in-silico pharmacokinetics studies showed the drug-likeness, non-toxic nature and safe oral administration of the synthesized compounds.

Prescribing antibiotics prudently—A survey of policy implementation drivers among physicians and veterinarians

BackgroundAs the antimicrobial resistance (AMR) problem accelerates, humans and animals are suffering from the consequences of infections with diminishing antimicrobial treatment options. Within the One Medicine and One Health mandate, which denotes a collaborative, multisectoral, and transdisciplinary approach to improve medicine and health across human and animal sectors, we investigate how human and veterinary medical practitioners apply their medical and policy knowledge in prescribing antimicrobials. Different regions and locations establish different intermediary policies and programs to support clinicians in that pursuit. In Hong Kong, there are locally adapted programs at governance and clinical levels in the human medical field. However, there is no locally adapted veterinary antibiotic prescription guideline or stewardship program, and veterinarians adopt overseas or international professions' antimicrobial use guidelines. Such a policy environment creates a natural experiment to compare local policy implementation conditions and clinicians' knowledge, perception, and practice. MethodWe construct the investigative survey tool by adaptation of Knowledge, Attitude, and Practice (KAP) and Capacity, Opportunity, and Motivation-Behavior (COMB) models. We identify, compare and contrast factors that influence clinicians' antimicrobial prescription behavior. The factors are considered both intrinsically, such as personal attributes, and extrinsically, such as societal and professional norms. FindingsThe absence of locally adopted antimicrobial guidelines influences AMR stewardship program implementation in local Hong Kong veterinary community. As medical allies, physicians and veterinarians share similar demographic influence, organization considerations and perception of public awareness. Both cohorts prescribe more prudently with more years-in-practice, time available to communicate with patients or caretakers, and public awareness and support.