scholarly journals In Situ Generation of Zinc Oxide Nanobushes on Microneedles as Antibacterial Coating

2018 ◽  
Vol 24 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Sharon W. T. Chew ◽  
Yongpeng Zeng ◽  
Mingyue Cui ◽  
Hao Chang ◽  
Mengjia Zheng ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Antimicrobial Property ◽  
Gram Negative Bacteria ◽  
Diffusion Test ◽  
Gram Negative ◽  
Antibacterial Coating ◽  
Agar Diffusion Test ◽  
Growth Method ◽  
In Situ Generation

This paper introduces a facile and scalable method to generate a layer of antibacterial coating on microneedles. The antibacterial coating (i.e., zinc oxide nanobushes) is generated on the surface of gold-coated polystyrene microneedles using the hydrothermal growth method. The antimicrobial property is examined using the agar diffusion test with both gram-positive and gram-negative bacteria.

scholarly journals Activity of Specialized Biomolecules against Gram-Positive and Gram-Negative Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 314 ◽  
Author(s):  
Tânia D. Tavares ◽  
Joana C. Antunes ◽  
Jorge Padrão ◽  
Ana I. Ribeiro ◽  
Andrea Zille ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Time Averaging ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Intracellular Space ◽  
Gram Negative ◽  
Tea Tree ◽  
Minimal Inhibitory Concentrations ◽  
Agar Diffusion Test ◽  
Short Period

The increased resistance of bacteria against conventional pharmaceutical solutions, the antibiotics, has raised serious health concerns. This has stimulated interest in the development of bio-based therapeutics with limited resistance, namely, essential oils (EOs) or antimicrobial peptides (AMPs). This study envisaged the evaluation of the antimicrobial efficacy of selected biomolecules, namely LL37, pexiganan, tea tree oil (TTO), cinnamon leaf oil (CLO) and niaouli oil (NO), against four bacteria commonly associated to nosocomial infections: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. The antibiotic vancomycin and silver nanoparticles (AgNPs) were used as control compounds for comparison purposes. The biomolecules were initially screened for their antibacterial efficacy using the agar-diffusion test, followed by the determination of minimal inhibitory concentrations (MICs), kill-time kinetics and the evaluation of the cell morphology upon 24 h exposure. All agents were effective against the selected bacteria. Interestingly, the AgNPs required a higher concentration (4000–1250 μg/mL) to induce the same effects as the AMPs (500–7.8 μg/mL) or EOs (365.2–19.7 μg/mL). Pexiganan and CLO were the most effective biomolecules, requiring lower concentrations to kill both Gram-positive and Gram-negative bacteria (62.5–7.8 μg/mL and 39.3–19.7 μg/mL, respectively), within a short period of time (averaging 2 h 15 min for all bacteria). Most biomolecules apparently disrupted the bacteria membrane stability due to the observed cell morphology deformation and by effecting on the intracellular space. AMPs were observed to induce morphological deformations and cellular content release, while EOs were seen to split and completely envelope bacteria. Data unraveled more of the potential of these new biomolecules as replacements for the conventional antibiotics and allowed us to take a step forward in the understanding of their mechanisms of action against infection-related bacteria.

scholarly journals In situ identification of Gram-negative bacteria in human lungs using a topical fluorescent peptide targeting lipid A

2018 ◽  
Vol 10 (464) ◽  
pp. eaal0033 ◽  
Author(s):  
Ahsan R. Akram ◽  
Sunay V. Chankeshwara ◽  
Emma Scholefield ◽  
Tashfeen Aslam ◽  
Neil McDonald ◽  
...  
Keyword(s):  
Lipid A ◽  
Respiratory Infections ◽  
Bacterial Species ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Human Lungs ◽  
Fluorescent Peptide ◽  
Bacterial Lipid

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time. We used optical endomicroscopy to visualize a water-soluble optical imaging probe based on the antimicrobial peptide polymyxin conjugated to an environmentally sensitive fluorophore. The probe was chemically stable and nontoxic and, after in-human intrapulmonary microdosing, enabled the specific detection of Gram-negative bacteria in distal human airways and alveoli within minutes. The results suggest that pulmonary molecular imaging using a topically administered fluorescent probe targeting bacterial lipid A is safe and practical, enabling rapid in situ identification of Gram-negative bacteria in humans.

Antimicrobial potential of synthesized zinc oxide nanoparticles against gram positive and gram negative bacteria

2013 ◽  
Vol 52 (25-27) ◽  
pp. 4969-4976 ◽  
Author(s):  
Edris Hoseinzadeh ◽  
Mohammad-Yosef Alikhani ◽  
Mohammad-Reza Samarghandi ◽  
Mehdi Shirzad-Siboni
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Potential

scholarly journals Biosynthesized Zinc Oxide Nanoparticles Disrupt Established Biofilms of Pathogenic Bacteria

2022 ◽  
Vol 12 (2) ◽  
pp. 710
Author(s):  
Fohad Mabood Husain ◽  
Faizan Abul Qais ◽  
Iqbal Ahmad ◽  
Mohammed Jamal Hakeem ◽  
Mohammad Hassan Baig ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Pathogenic Bacteria ◽  
Oxide Nanoparticles ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Zno Nps ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

Global emergence and persistence of the multidrug-resistant microbes have created a new problem for management of diseases associated with infections. The development of antimicrobial resistance is mainly due to the sub-judicious and unprescribed used of antimicrobials both in healthcare and the environment. Biofilms are important due to their role in microbial infections and hence are considered a novel target in discovery of new antibacterial or antibiofilm agents. In this article, zinc oxide nanoparticles (ZnO-NPs) were prepared using extract of Plumbago zeylanica. ZnO-NPs were characterized and then their antibiofilm activity was tested against Gram-positive and Gram-negative bacteria. The ZnO-NPs were polydispersed, and the average size was obtained as 24.62 nm. The presence of many functional groups indicated that phytocompounds of P. zeylanica were responsible for the synthesis, capping, and stabilization of ZnO-NPs. Synthesized NPs inhibited the biofilm formation of E. coli, S. aureus, and P. aeruginosa by 62.80%, 71.57%, and 77.69%, respectively. Likewise, concentration-dependent inhibition of the EPS production was recorded in all test bacteria. Microscopic examination of the biofilms revealed that ZnO-NPs reduced the bacterial colonization on solid support and altered the architecture of the biofilms. ZnO-NPs also remarkably eradicated the preformed biofilms of the test bacteria up to 52.69%, 59.79%, and 67.22% recorded for E. coli, S. aureus, P. aeruginosa, respectively. The findings reveal the ability of green synthesized zinc oxide nanoparticles to inhibit, as well as eradicate, the biofilms of Gram-positive and Gram-negative bacteria.

scholarly journals Asymmetric one-pot synthesis of cyclopropanes

2016 ◽  
Vol 35 (1) ◽  
pp. 45
Author(s):  
Naoufel Ben Hamadi ◽  
Ahlem Guesmi ◽  
Wided Nouira
Keyword(s):  
Escherichia Coli ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Protecting Group ◽  
Gram Positive ◽  
One Pot ◽  
Gram Negative ◽  
Activity Screening ◽  
High Yields

Cycloaddition of the diazoalkanes to electron-deficient olefins (in situ) affords polysubstituted cyclopropanes in high yields (up to 85%). Deprotection of the ketal protecting group provided water-soluble cyclopropane-bearing carbohydrate in good yields. Antimicrobial activity screening of the synthesized compounds 8 and 9, utilizing a variety of Gram-positive (Staphylococcus aureus and Enterococcus fecalis), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and yeast (Candida albicans), exhibited that all the prepared analogues acquire promising activities against both Gram-positive and Gram-negative bacteria especially compounds 9b and 9c (antimicrobial active agents against Gram-negative bacteria).

scholarly journals Synthesis, Characterization and Antimicrobial Activities of Co (III) and Fe (III) Complexes of Imino-N-heterocyclic Carbenes Ligands

2021 ◽  
pp. 59-67
Author(s):  
Samaila Abubakar ◽  
Musa Muktari ◽  
Rejoice Atiko
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhi ◽  
Antimicrobial Activities ◽  
Heterocyclic Carbenes ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria

The synthesis and antimicrobial application of Co (III) and Fe (III) complexes of imine functionalized N-heterocyclic carbene (Imino-NHC) ligands is reported. The ligand precursors 1-(2-[(hydroxyl-benzylidene)-amino]-ethyl)-3-R-3H-imidazol-1-ium bromide where R = pyridyl (1a) and benzyl (1b) have been reported in our previous work. The in-situ generated ligands of 1a and 1b have been successfully coordinated to CoBr2 and [FeI(Cp)(CO)2] leading to the isolation of air-stable N^C^N^O four coordinate Co(III)  complex 2 and a six-coordinate Fe(III) complex 3. The synthesised complexes were both found to be NMR inactive hence were characterize using FTIR and LRMS. The complexes were screened for antimicrobial activities against four gram-negative bacteria Escherichia Coli (E-coli), Shigella, Klebsiella pneumoniae (K. Pneumoniae) and Salmonella typhi (S. typhi) and a gram positive bacteria Staphylocossus aureus (S. aureus). The antimicrobial test was conducted using disc diffusion methods and based on the concentrations of 100, 200, 300, 400 and 500 µg/ mL, significant activities were recorded for both cobalt and the iron complexes.

Structural changes in the model of the outer cell membrane of Gram-negative bacteria interacting with melittin: An in situ spectroelectrochemical study

2020 ◽  
Author(s):  
Izabella Brand ◽  
Bishoy Khairalla
Keyword(s):  
Cell Membrane ◽  
Structural Changes ◽  
Supramolecular Assembly ◽  
Outer Cell ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Langmuir Blodgett ◽  
A Cell ◽  
Experimental Challenge

A cell membrane of Gram-negative bacteria interacting with an antimicrobial peptide represents a complex supramolecular assembly. Fabrication of the models of bacterial cell membranes remains a large experimental challenge. Langmuir-Blodgett...

scholarly journals Comparative Study of the Bacteriological Activity of Zinc Oxide and Copper Oxide Nanoparticles

2019 ◽  
Vol 6 (1) ◽  
pp. 63-72
Author(s):  
Abdelali Merah ◽  
Abdenabi Abidi ◽  
Hana Merad ◽  
Noureddine Gherraf ◽  
Mostepha Iezid ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Copper Oxide ◽  
Metal Oxides ◽  
Bactericidal Effect ◽  
Cuo Nanoparticles ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Abstract Interest in nanomaterials, especially metal oxides, in the fight against resistant and constantly changing bacterial strains, is more and more expressed. Their very high reactivity, resulting from their large surface area, promoted them to the rank of potential successors of antibiotics. Our work consisted of the synthesis of zinc oxide (ZnO) and copper oxide (CuO) in the nanoparticle state and the study of their bactericidal effect on various Gram-negative and Gram-positive bacterial strains. The nanoparticles of metal oxides have been synthesized by sol-gel method. Qualitative analysis and characterization by UV / Visible and infrared spectrophotometry and X-ray diffraction confirmed that the synthetic products are crystalline. The application of the Scherrer equation allows to determine the size of the two metal oxides, namely: 76.94 nm for ZnO and 24.86 nm for CuO. The bactericidal effect of ZnO and CuO nanoparticles was tested on Gram-positive bacteria (Staphylococcus aureus, Staphylococcus hominis, Staphylococcus haemolyticus, Enterococcus facials) and Gram-negative bacteria (Escherichia coli, Schigella, Klepsiella pneumoniae and Pseudomonas aeruginosa). The results indicate that the tested metal oxides nanoparticles have an effect that varies depending on bacterial species. Indeed, Gram-positive bacteria show greater sensitivity to ZnO nanoparticles whereas Gram-negative bacteria are more sensitive to CuO nanoparticles.

scholarly journals A Xenorhabdus budapestensis entomopatogén baktérium sejtmentes fermentlevének és tisztítottfehérje-frakciójának antimikrobiális hatása néhány zoonoticus baktériumra

2015 ◽  
Vol 156 (44) ◽  
pp. 1782-1786 ◽  
Author(s):  
Erzsébet Burgettiné Böszörményi ◽  
István Barcs ◽  
Gyula Domján ◽  
Katalin Bélafiné Bakó ◽  
András Fodor ◽  
...  
Keyword(s):  
Pasteurella Multocida ◽  
Antibacterial Effect ◽  
Conditioned Media ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Salmonella Gallinarum ◽  
Gram Positive Bacteria ◽  
Agar Diffusion Test

Introduction: Many multi-resistant patogens appear continuously resulting in a permanent need for the development of novel antibiotics. A large number of antibiotics introduced in clinical and veterinary practices are not effective. Antibacterial peptides with unusual mode of action may represent a promising option against multi-resistant pathogens. The entomopathogenic Xenorhabdus budapestensis bacteria produce several different antimicrobial peptides compounds such as bicornutin-A and fabclavin. Aim: The aim of the authors was to evaluate the in vitro antibacterial effect of Xenorhabdus budapestensis using zoonotic patogen bacteria. Method: Cell-free conditioned media and purified peptide fractions of Xenorhabdus budapestensis were tested on Gram-positive (Rhodococcus equi, Erysipelothrix rhusiopathia, Staphylococcus aureus, Streptococcus equi, Corynebacterium pseudotuberculosis, Listeria monocytagenes) and Gram-negative bacteria (Salmonella gallinarum, Salmonella derbi, Bordatella bronchoseptica, Escherichia coli, Pasteurella multocida, Aeromonas hydrophila) using agar diffusion test on blood agar plates. Results: It was found that Xenorhabdus budapestensis bacteria produced compounds with strong and dose-dependent effects on the tested organisms. Purified peptid fraction exerted a more marked effect than cell free conditioned media. Gram-positive bacteria were more sensitive to this antibacterial effect than Gram-negative bacteria. Conclusions: Antibacterial peptide compound from Xenorhabdus budapestensis exert marked antibacterial effect on zoonotic patogen bacteria and they should be further evaluated in future for their potential use in the control or prevention of zoonoses. Orv. Hetil., 2015, 156(44), 1782–1786.

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