Bactericidal effect of gentamicin-induced membrane vesicles derived fromPseudomonas aeruginosaPAO1 on gram-positive bacteria

2002 ◽  
Vol 48 (9) ◽  
pp. 810-820 ◽  
Author(s):  
Kelly L MacDonald ◽  
Terry J Beveridge
Keyword(s):  
Electron Microscopy ◽  
Therapeutic Potential ◽  
Hydrophobic Interaction Chromatography ◽  
Membrane Vesicles ◽  
Bactericidal Effect ◽  
Gram Positive ◽  
Thin Sections ◽  
Gram Negative ◽  
Induced Membrane ◽  
Gram Positive Bacteria

Previous studies have shown that gentamicin-induced membrane vesicles (g-MVs) from Pseudomonas aeruginosa PAO1 possess both the antibiotic (gentamicin) and a potent peptidoglycan hydrolase (PGase; autolysin) that is effective in killing gram-negative pathogens. This present study evaluated the therapeutic potential of g-MVs against four gram-positive bacteria. Bactericidal assays and electron microscopy of thin sections revealed that Bacillus subtilis 168 and Staphylococcus aureus D2C were susceptible to killing mediated by g-MVs, Listeria monocytogenes ATCC 19113 was slightly susceptible, whereas Enterococcus hirae ATCC 9790 was unaffected. g-MVs were generally more effective against the bacteria than was soluble gentamicin, suggesting they could have more killing power than natural membrane vesicles containing no antibiotic. Electron microscopy and hydrophobic interaction chromatography showed that more membrane vesicles (MVs) initially attached to B. subtilis (hydrophilic) than to predominantly hydrophobic E. hirae, L. monocytogenes, and S. aureus. Zymograms containing murein sacculi as an enzyme substrate illustrated that all organisms except E. hirae were sensitive to the 26-kDa autolysin to varying degrees. Peptidoglycan O-acetylation did not influence susceptibility to MV-mediated lysis. Though not universally effective, the g-MV delivery system remains a promising therapeutic alternative for specific gram-positive infections.Key words: gram-negative membrane vesicles, gentamicin, autolysin.

Photodynamic Treatment: A Novel Method for Sanitation of Food Handling and Food Processing Surfaces

2009 ◽  
Vol 72 (5) ◽  
pp. 1020-1024 ◽  
Author(s):  
LUBOV Y. BROVKO ◽  
ANN MEYER ◽  
ARVINDER S. TIWANA ◽  
WEI CHEN ◽  
HAN LIU ◽  
...  
Keyword(s):  
Malachite Green ◽  
Rose Bengal ◽  
Bactericidal Effect ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Bacterial Killing ◽  
Killing Effect ◽  
Gram Negative ◽  
Cell Numbers ◽  
Gram Positive Bacteria

The photodynamic bactericidal effect of the photoactive dyes acriflavine neutral, rose bengal, phloxine B, and malachite green (oxalate salt) at concentrations of 5 to 5,000 μg/ml against two gram-negative strains (Escherichia coli LJH 128 and Salmonella Typhimurium C1058), two gram-positive strains (Bacillus sp. C578 and Listeria monocytogenes LJH 375), and yeast (Saccharomyces cerevisiae C1172) was investigated. Incubation of the investigated bacteria with acriflavine neutral under illumination resulted in a significant reduction in cell numbers compared with dark incubation. Rose bengal caused a significant killing effect for bacteria incubated both in the dark and under illumination. Malachite green was active against gram-positive bacteria under illumination and did not affect gram-negative bacteria or yeasts. Incubation with phloxine B resulted in a significant decline in cell numbers for gram-positive bacteria, both in the dark and under illumination; gram-negative bacteria and yeasts were unaffected. Conjugation of rose bengal and phloxine B with poly(vinyl amine) resulted in an enhanced bactericidal effect during both dark and light incubation. This was explained by electrostatic interaction of the polymer with the cell surface, which resulted in closer contact of the photoactive dye and cell. No killing effect was observed for yeasts incubated with dye conjugates. Filter paper treated with dye–poly(vinyl amine) conjugates showed high photodynamic bactericidal activity against the bacterial strains, but not against the yeasts. The extent of bacterial killing depended on the nature and concentration of the dye conjugate and the type of microorganism. The presented data suggest that a photodynamic approach for constructing “self-decontaminating” materials has potential.

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 Antibacterial properties of silver nanoparticles and their membranotrophic action

2021 ◽  
pp. 64-71
Author(s):  
Lilit S. Gabrielyan ◽  
Armen A. Trchounian
Keyword(s):  
Antibacterial Properties ◽  
Bactericidal Effect ◽  
H2 Production ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Silver Nps ◽  
H2 Yield ◽  
K 12 ◽  
Energy Dependent

Nowadays, metal nanoparticles (NPs) can be considered as alternative agents for overcoming antibiotic resistance. The effect of silver NPs on gram-positive (Enterococcus hirae ATCC9790, Staphylococcus aureus MDC5233) and gram-negative (Escherichia coli K-12, Salmonella typhimurium MDC1759) bacteria have been investigated in this work. Silver NPs demonstrated antibacterial activity against the bacteria used, expressed in the decrease of the specific growth rate and the number of colony forming units. Moreover, the bactericidal effect of silver NPs on gram-positive bacteria was more pronounced than on gram-negative bacteria. In order to find out the mechanisms of NPs’ effects, the change of the redox potential, the hydrogen (H2) production ability, and the protons flux across the bacterial membrane have been also studied. The addition of NPs led to inhibition of H2 yield and to change of the energy-dependent proton flux through Fo F1-ATPase, indicating the silver NPs effect on the activity of membrane-bound enzymes. The data obtained point out that silver NPs show a pronounced antibacterial effect against the studied bacteria and can be used in biomedicine.

scholarly journals Extracellular vesicles: An emerging platform in gram-positive bacteria

2020 ◽  
Vol 7 (12) ◽  
pp. 312-322
Author(s):  
Swagata Bose ◽  
Shifu Aggarwal ◽  
Durg Vijai Singh ◽  
Narottam Acharya
Keyword(s):  
Extracellular Vesicles ◽  
Intercellular Communication ◽  
Pathogenic Bacteria ◽  
Membrane Vesicles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Functional Aspects ◽  
As Stress

Extracellular vesicles (EV), also known as membrane vesicles, are produced as an end product of secretion by both pathogenic and non-pathogenic bacteria. Several reports suggest that archaea, gram-negative bacteria, and eukaryotic cells secrete membrane vesicles as a means for cell-free intercellular communication. EVs influence intercellular communication by transferring a myriad of biomolecules including genetic information. Also, EVs have been implicated in many phenomena such as stress response, intercellular competition, lateral gene transfer, and pathogenicity. However, the cellular process of secreting EVs in gram-positive bacteria is less studied. A notion with the thick cell-walled microbes such as gram-positive bacteria is that the EV release is impossible among them. The role of gram-positive EVs in health and diseases is being studied gradually. Being nano-sized, the EVs from gram-positive bacteria carry a diversity of cargo compounds that have a role in bacterial competition, survival, invasion, host immune evasion, and infection. In this review, we summarise the current understanding of the EVs produced by gram-positive bacteria. Also, we discuss the functional aspects of these components while comparing them with gram-negative bacteria.

scholarly journals Nanocomposites with ornidazole—antibacterial and antiadhesive agents against Gram-positive and Gram-negative bacteria

2020 ◽  
Vol 10 (8) ◽  
pp. 3193-3203
Author(s):  
I. Furtat ◽  
M. Lupatsii ◽  
T. Murlanova ◽  
P. Vakuliuk ◽  
A. Gaidai ◽  
...  
Keyword(s):  
Bacterial Adhesion ◽  
Therapeutic Potential ◽  
Antimicrobial Properties ◽  
Bactericidal Effect ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Antimicrobial Spectrum ◽  
Gram Negative ◽  
Index Index ◽  
Adhesion Index

AbstractAntimicrobial resistance of many microbial species can cause to thousands of deaths worldwide, in this regard new therapeutic strategies have to be invented. To address the question, we have prepared nanocomposites on the basis of pyrogenic silicon dioxide with ornidazole immobilized on the surface (ornidasil) and studied their antimicrobial properties and the therapeutic potential. It has also been shown, that in comparison with pure ornidazole the addition of ornidazole to nanocomposite composition can enhance the antimicrobial spectrum, including Gram-positive and Gram-negative bacteria. The most significant bactericidal effect has been reached after more than 24-h treatment with the nanocomposite. Antiadhesive properties of nanocomposite materials were studied using blood types OO+, AO+, BO+, AB+, the degree of bacterial adhesion was estimated using three indexes: average adhesion index, index of erythrocytes involvement, index of microbial adhesion. The effectiveness of the treatment with the nanocomposites obtained was studied on complicated wounds of various etiologies, in particular the wounds caused by diabetic foot syndrome.

scholarly journals Pytochemical screening and evaluation antimicrobial activity of the methanol extract of Ficus carica

2021 ◽  
Vol 12 (1) ◽  
pp. 1-9
Author(s):  
Belattar Hakima ◽  
Sara Himour ◽  
Abdelouahab Yahia
Keyword(s):  
Agar Plate ◽  
Bactericidal Effect ◽  
Ficus Carica ◽  
Diffusion Method ◽  
Klebsiella Pneumonia ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Methanolic Extracts ◽  
Antibacterial Assay

Fig tree (Ficus carica Linn.) was appreciated as food and for its medicinal properties, it grows in Mediterranean region, and it is admirably adapted to the conditions of Algeria. The use of natural resources to treat and cure diseases is an old and still widespread method. The objective of this work was to evaluate the antibacterial activity that exists through methanolic extracts of fig leaves grown in the Algerian environment. Antibacterial assay was carried out via disc diffusion method to measure the diameter of the zone of inhibition on the Müller-Hinton agar plate against four selected bacteria strains Staphylococcus aureus (Gram positive) and Pseudomonas aeruginosa, Escherichia coli, klebsiella pneumonia (Gram negative), in addition to the detection of some active compounds was carried out by phychemical screening. The result obtained showed that F. carica extracts revealed the presence of flavonoids, saponins, tannin, alkaloids. The presence of secondary metabolites made in these extracts is the cause of the observed antimicrobial potential. Consequently, all extracts exhibited the bactericidal effect towards the bacteria tested, while the crude extract of methanol was active against Gram positive bacteria more than Gram negative bacteria. In this study, the potential for development of alternative antibiotics derived from the methalonic extract of fig leaves was highlighted.

scholarly journals Antibacterial Efficacy of Raw and Processed Honey

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
D. P. Mohapatra ◽  
V. Thakur ◽  
S. K. Brar
Keyword(s):  
Antibacterial Activity ◽  
Micrococcus Luteus ◽  
Alternative Therapy ◽  
Bactericidal Effect ◽  
Salmonella Typhi ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

In vitro antibacterial activity of methanol, ethanol, and ethyl acetate extracts of raw and processed honey was tested against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Enterococcus faecalis, and Micrococcus luteus) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi). Both types of honey showed antibacterial activity against tested organisms with the zone of inhibition (ZOI) ranging from 6.94 to 37.94 mm, while E. coli, S. typhi, and P. aeruginosa showed that sensibility towards all the extracts with ZOI ranges between 13.09 to 37.94 mm. The methanol extract showed more potent activity than other organic extracts. Gram-negative bacteria were found to be more susceptible as compared to Gram-positive bacteria except E. faecalis. The broth microdilution assay gave minimum inhibitory concentrations (MIC) value of 625 μg/mL, while the minimum bactericidal concentration (MBC) ranges between 625 μg/mL 2500 μg/mL. The study showed that honey has antibacterial activity (bacteriostatic and bactericidal effect), similar to antibiotics, against test organisms and provides alternative therapy against certain bacteria.

scholarly journals Zinc Oxide Nanoparticles for Water Purification

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4747
Author(s):  
Angela Spoială ◽  
Cornelia-Ioana Ilie ◽  
Roxana-Doina Trușcă ◽  
Ovidiu-Cristian Oprea ◽  
Vasile-Adrian Surdu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Zno Nanoparticles ◽  
Zinc Oxide Nanoparticles ◽  
Precipitation Method ◽  
Oxide Nanoparticles ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

In this study, zinc oxide nanoparticles were synthesized through a simple co-precipitation method starting from zinc acetate dihydrate and sodium hydroxide as reactants. The as-obtained ZnO nanoparticles were morphologically and structurally characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photocatalytic activity, and by determining the antimicrobial activity against Gram-negative and Gram-positive bacteria. The XRD pattern of the zinc oxide nanoparticles showed the wurtzite hexagonal structure, and its purity highlighted that the crystallinity correlated with the presence of a single product, zinc oxide. The ZnO nanoparticles have an average crystallite size of 19 ± 11 nm, which is in accordance with the microscopic data. ZnO nanoparticles were tested against methyl orange, used as a model pollutant, and it was found that they exhibit strong photocatalytic activity against this dye. The antibacterial activity of ZnO nanoparticles was tested against Gram-negative and Gram-positive strains (Escherichia coli, Staphylococcus aureus, and Candida albicans). The strongest activity was found against Gram-positive bacteria (S. aureus).

scholarly journals Gram-Negative Bacteria Produce Membrane Vesicles Which Are Capable of Killing Other Bacteria

1998 ◽  
Vol 180 (20) ◽  
pp. 5478-5483 ◽  
Author(s):  
Zusheng Li ◽  
Anthony J. Clarke ◽  
Terry J. Beveridge
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Membrane Vesicles ◽  
Lytic Activity ◽  
Gram Negative Bacteria ◽  
Modus Operandi ◽  
Gram Positive ◽  
Gram Negative ◽  
Peptidoglycan Hydrolases

ABSTRACT Naturally produced membrane vesicles (MVs), isolated from 15 strains of gram-negative bacteria (Citrobacter,Enterobacter, Escherichia,Klebsiella, Morganella, Proteus,Salmonella, and Shigella strains), lysed many gram-positive (including Mycobacterium) and gram-negative cultures. Peptidoglycan zymograms suggested that MVs contained peptidoglycan hydrolases, and electron microscopy revealed that the murein sacculi were digested, confirming a previous modus operandi (J. L. Kadurugamuwa and T. J. Beveridge, J. Bacteriol. 174:2767–2774, 1996). MV-sensitive bacteria possessed A1α, A4α, A1γ, A2α, and A4γ peptidoglycan chemotypes, whereas A3α, A3β, A3γ, A4β, B1α, and B1β chemotypes were not affected. Pseudomonas aeruginosa PAO1 vesicles possessed the most lytic activity.

scholarly journals Detection of Bacterial Membrane Vesicles by NOD-Like Receptors

2021 ◽  
Vol 22 (3) ◽  
pp. 1005
Author(s):  
Ella L. Johnston ◽  
Begoña Heras ◽  
Thomas A. Kufer ◽  
Maria Kaparakis-Liaskos
Keyword(s):  
Inflammatory Diseases ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Innate Immune ◽  
Host Cells ◽  
Bacterial Membrane ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Key Driver

Bacterial membrane vesicles (BMVs) are nanoparticles produced by both Gram-negative and Gram-positive bacteria that can function to modulate immunity in the host. Both outer membrane vesicles (OMVs) and membrane vesicles (MVs), which are released by Gram-negative and Gram-positive bacteria, respectively, contain cargo derived from their parent bacterium, including immune stimulating molecules such as proteins, lipids and nucleic acids. Of these, peptidoglycan (PG) and lipopolysaccharide (LPS) are able to activate host innate immune pattern recognition receptors (PRRs), known as NOD-like receptors (NLRs), such as nucleotide-binding oligomerisation domain-containing protein (NOD) 1, NOD2 and NLRP3. NLR activation is a key driver of inflammation in the host, and BMVs derived from both pathogenic and commensal bacteria have been shown to package PG and LPS in order to modulate the host immune response using NLR-dependent mechanisms. Here, we discuss the packaging of immunostimulatory cargo within OMVs and MVs, their detection by NLRs and the cytokines produced by host cells in response to their detection. Additionally, commensal derived BMVs are thought to shape immunity and contribute to homeostasis in the gut, therefore we also highlight the interactions of commensal derived BMVs with NLRs and their roles in limiting inflammatory diseases.

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