scholarly journals Mechanism of Decreased Susceptibility for Gram-negative Bacteria and Synergistic Effect with Ampicillin of Indole-3-carbinol

2008 ◽  
Vol 31 (9) ◽  
pp. 1798-1801 ◽  
Author(s):  
Woo Sang Sung ◽  
Dong Gun Lee
Keyword(s):  
Synergistic Effect ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals Packaging Covered with Antiviral and Antibacterial Coatings Based on ZnO Nanoparticles Supplemented with Geraniol and Carvacrol

2021 ◽  
Vol 22 (4) ◽  
pp. 1717
Author(s):  
Małgorzata Mizielińska ◽  
Paweł Nawrotek ◽  
Xymena Stachurska ◽  
Magdalena Ordon ◽  
Artur Bartkowiak
Keyword(s):  
Synergistic Effect ◽  
Moderate Activity ◽  
Gram Negative Bacteria ◽  
Human Pathogen ◽  
Safety Measures ◽  
Gram Negative ◽  
Airborne Viruses ◽  
Respiratory Droplets ◽  
Active Substances ◽  
External Coating

The purpose of the study was to obtain an external coating based on nanoparticles of ZnO, carvacrol, and geraniol that could be active against viruses such as SARS-Co-V2. Additionally, the synergistic effect of the chosen substances in coatings was analyzed. The goal of the study was to measure the possible antibacterial activity of the coatings obtained. Testing antiviral activity with human pathogen viruses, such as SARS-Co-V2, requires immense safety measures. Bacteriophages such as phi 6 phage represent good surrogates for the study of airborne viruses. The results of the study indicated that the ZC1 and ZG1 coatings containing an increased amount of geraniol or carvacrol and a very small amount of nanoZnO were found to be active against Gram-positive and Gram-negative bacteria. It is also important that a synergistic effect between these active substances was noted. This explains why polyethylene (PE) films covered with the ZC1 or ZG1 coatings (as internal coatings) were found to be the best packaging materials to extend the quality and freshness of food products. The same coatings may be used as the external coatings with antiviral properties. The ZC1 and ZG1 coatings showed moderate activity against the phi 6 phage that has been selected as a surrogate for viruses such as coronaviruses. It can be assumed that coatings ZG1 and ZC1 will also be active against SARS-CoV-2 that is transmitted via respiratory droplets.

scholarly journals Novel Modifications of Nonribosomal Peptides from Brevibacillus laterosporus MG64 and Investigation of Their Mode of Action

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Zhibo Li ◽  
Reinder H. de Vries ◽  
Parichita Chakraborty ◽  
Chunxu Song ◽  
Xinghong Zhao ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Secondary Metabolites ◽  
Cell Membrane ◽  
Synergistic Effect ◽  
Mode Of Action ◽  
Nonribosomal Peptides ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Brevibacillus Laterosporus ◽  
Reductase Domain

ABSTRACT Nonribosomal peptides (NRPs) are a class of secondary metabolites usually produced by microorganisms. They are of paramount importance in different applications, including biocontrol and pharmacy. Brevibacillus spp. are a rich source of NRPs yet have received little attention. In this study, we characterize four novel bogorol variants (bogorols I to L, cationic linear lipopeptides) and four succilins (succilins I to L, containing a succinyl group that is attached to the Orn3/Lys3 in bogorols I to L) from the biocontrol strain Brevibacillus laterosporus MG64. Further investigation revealed that the bogorol family of peptides employs an adenylation pathway for lipoinitiation, different from the usual pattern, which is based on an external ligase and coenzyme A. Moreover, the formation of valinol was proven to be mediated by a terminal reductase domain and a reductase encoded by the bogI gene. Furthermore, succinylation, which is a novel type of modification in the family of bogorols, was discovered. Its occurrence requires a high concentration of the substrate (bogorols), but its responsible enzyme remains unknown. Bogorols display potent activity against both Gram-positive and Gram-negative bacteria. Investigation of their mode of action reveals that bogorols form pores in the cell membrane of both Gram-positive and Gram-negative bacteria. The combination of bogorols and relacidines, another class of NRPs produced by B. laterosporus MG64, displays a synergistic effect on different pathogens, suggesting the great potential of both peptides as well as their producer B. laterosporus MG64 for broad applications. Our study provides a further understanding of the bogorol family of peptides as well as their applications. IMPORTANCE NRPs form a class of secondary metabolites with biocontrol and pharmaceutical potential. This work describes the identification of novel bogorol variants and succinylated bogorols (namely, succilins) and further investigates their biosynthetic pathway and mode of action. Adenylation domain-mediated lipoinitiation of bogorols represents a novel pathway by which NRPs incorporate fatty acid tails. This pathway provides the possibility to engineer the lipid tail of NRPs without identifying a fatty acid coenzyme ligase, which is usually not present in the biosynthetic gene cluster. The terminal reductase domain (TD) and BogI-mediated valinol formation and their effect on the biological activity of bogorols are revealed. Succinylation, which is rarely reported in NRPs, was discovered in the bogorol family of peptides. We demonstrate that bogorols combat bacterial pathogens by forming pores in the cell membrane. We also report the synergistic effect of two natural products (relacidine B and bogorol K) produced by the same strain, which is relevant for competition for a niche.

scholarly journals Synergistic Effect of Propidium Iodide and Small Molecule Antibiotics with the Antimicrobial Peptide Dendrimer G3KL against Gram-Negative Bacteria

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5643
Author(s):  
Bee-Ha Gan ◽  
Xingguang Cai ◽  
Sacha Javor ◽  
Thilo Köhler ◽  
Jean-Louis Reymond
Keyword(s):  
Synergistic Effect ◽  
Propidium Iodide ◽  
Synergistic Effects ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Bacterial Killing ◽  
Gram Negative ◽  
Outer Membranes ◽  
New Antibiotics

There is an urgent need to develop new antibiotics against multidrug-resistant bacteria. Many antimicrobial peptides (AMPs) are active against such bacteria and often act by destabilizing membranes, a mechanism that can also be used to permeabilize bacteria to other antibiotics, resulting in synergistic effects. We recently showed that G3KL, an AMP with a multibranched dendritic topology of the peptide chain, permeabilizes the inner and outer membranes of Gram-negative bacteria including multidrug-resistant strains, leading to efficient bacterial killing. Here, we show that permeabilization of the outer and inner membranes of Pseudomonas aeruginosa by G3KL, initially detected using the DNA-binding fluorogenic dye propidium iodide (PI), also leads to a synergistic effect between G3KL and PI in this bacterium. We also identify a synergistic effect between G3KL and six different antibiotics against the Gram-negative Klebsiella pneumoniae, against which G3KL is inactive.

Synergistic Activity of Phenolic Compounds of Some Plants Against Bacteria

2021 ◽  
Vol 8 (6) ◽  
pp. 102-110
Author(s):  
Roaa M. H. Shoker
Keyword(s):  
Antimicrobial Activity ◽  
Phenolic Compounds ◽  
Synergistic Effect ◽  
Pathogenic Bacteria ◽  
Total Concentration ◽  
Sesamum Indicum ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Gram Negative ◽  
Phenolic Extracts

Medicinal plants produce great groups of secondary metabolites which are essential for medicine purpose, one of them phenolic compounds, antimicrobial activity of phenolic compounds which derivative from plants has been examined for several years. The phenolic extracts of Sesamum indicum and Pimpinella anisum seeds have antibacterial action against Gram positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), (Acinetobacter baumannii), and (Pseudomonas aeruginosa) (Proteus mirabilis). The current findings show that the synergistic impact of phenolic extracts from S. indicum and P. anisum is active against a variety of pathogenic bacteria, and that the synergistic effect for two plants is more antibacterial than phenolic extracts from one plant.  The results indicated Gram- negative (P. aeruginosa) more effected by plants, than Gram-negative (S. aureus) which have the lower effects. The results of HPLC indicated Sesame (S. indicum) have total concentration of phenolic compounds was (1313.7 µg/ml) higher than total concentration of phenolic compounds of Anise (P. anisum) (220.991 µg/ml), and have varied types of phenolic compounds were Pyrogallol, Gallic acid, Rutin, Kaempferol, Cinnamaldehyde, Qurctin, Eugenol, Lignan with different concentration. From this study may be conclusion Synergistic effect for two plants have more antibacterial than phenolic extracts of one plant, and Sesame (S. indicum) have higher antimicrobial activity than Anise (P. anisum).

Development of benzimidazole-based derivatives as antimicrobial agents and their synergistic effect with colistin against gram-negative bacteria

2020 ◽  
Vol 186 ◽  
pp. 111850 ◽  
Author(s):  
Eman M.E. Dokla ◽  
Nader S. Abutaleb ◽  
Sandra N. Milik ◽  
Daoyi Li ◽  
Karim El-Baz ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Antimicrobial Agents ◽  
Gram Negative Bacteria ◽  
Gram Negative

Biogenic synthesis of silver nanoparticles and their synergistic effect with antibiotics: a study against gram-positive and gram-negative bacteria

2010 ◽  
Vol 6 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Amanulla Mohammed Fayaz ◽  
Kulandaivelu Balaji ◽  
Morukattu Girilal ◽  
Ruchi Yadav ◽  
Pudupalayam Thangavelu Kalaichelvan ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Synergistic Effect ◽  
Gram Negative Bacteria ◽  
Biogenic Synthesis ◽  
Gram Positive ◽  
Gram Negative

scholarly journals Antibacterial Effect of Some Palestinian Plant Extracts against Clinical Multidrug-Resistant Gram- Negative Bacteria: A possible synergism with antibiotics

2020 ◽  
Vol 19 (3) ◽  
pp. 509-519
Author(s):  
Emad Abou Elkhair ◽  
Tarek A El Bashiti ◽  
Atef A Masad ◽  
Wesam S Abu Draz
Keyword(s):  
Antibacterial Activity ◽  
Synergistic Effect ◽  
Essential Oils ◽  
Plant Extracts ◽  
Synergistic Effects ◽  
Medical Science ◽  
Average Diameter ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Gram Negative

Objectives: The present study was designed to screen the antibacterial and synergistic effects of Allium sativum, Ecballiumelaterium, Pelargoniumgraveolens, Rosmarinusofficinalis, Phagnalonrupestre and Rutagraveolens plant extracts and essential oils against the followingclinical multidrug-resistant(MDR) Gram negative pathogenic isolates: Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. Methods: All extracts and essential oils were screened for their antibacterial activity and synergistic effect in combination with known antibiotics.The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) of the plant extracts were assessed. Results: Our results revealed that, the average diameter of inhibition zones ranged from: 7-14 mm, 7-17 mm, 8-17 mm and 7-13 mm for water, ethanol, methanol and EOs extracts, respectively. The MICs and MBCs were determined for extracts which showed antibacterial activity. The average MICs values ranged from 1.6-100 mg/ml, 1.6-50 mg/ml, 0.39 -50 mg/ml and 3.13-100 μl/ml for water, ethanol, methanol and EOs extracts, respectively. While MBCs values ranged from 25->200 mg/ml, 25- 200 mg/ml and 50->200 μl/ml for water, ethanol, methanol and EOs extracts, respectively. The antibacterial activity of the afore mentioned plant extracts combined with Ciprofloxacin (CIP), Ampicillin (AM), Cefotaxime (CTX), Nalidixic acid (NA), Norofloxacin (NOR), Cefuroxime (CXM), Cefaclor (CF), Ofloxacin (OFX), Cefalexin (CL), Tetracycline (TE), Rifampicin (RIF), Amoxyclav (AMC) and Amikacin (AK) had different degrees of synergism against the selectedbacteria.Essential oils (Eos) of screened plants had the best synergism with antibiotics than the plant extracts against the tested bacteria. The best synergism was noticed in the Eos of A. sativum, P. graveolens and R. officinalis. Conclusion: It was concluded that the synergistic effect of antibiotics and plant extracts is promising approach fortreating infectious diseases caused byMDR Gram negative bacteria. Bangladesh Journal of Medical Science Vol.19(3) 2020 p.509-519

scholarly journals Equisetin Restores Colistin Sensitivity against Multi-Drug Resistant Gram-Negative Bacteria

Antibiotics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1263
Author(s):  
Qi Zhang ◽  
Shang Chen ◽  
Xiaojia Liu ◽  
Wenhan Lin ◽  
Kui Zhu
Keyword(s):  
Synergistic Effect ◽  
New Drugs ◽  
Infection Model ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Drug Resistant ◽  
Gram Negative ◽  
E Coli ◽  
Hydrophobic Barrier ◽  
Time Kill

The overuse of antibiotics and the scarcity of new drugs have led to a serious antimicrobial resistance crisis, especially for multi-drug resistant (MDR) Gram-negative bacteria. In the present study, we investigated the antimicrobial activity of a marine antibiotic equisetin in combination with colistin against Gram-negative bacteria and explored the mechanisms of synergistic activity. We tested the synergistic effect of equisetin in combination with colistin on 23 clinical mcr-1 positive isolates and found that 4 µg/mL equisetin combined with 1 µg/mL colistin showed 100% inhibition. Consistently, equisetin restored the sensitivity of 10 species of mcr-1 positive Gram-negative bacteria to colistin. The combination of equisetin and colistin quickly killed 99.9% bacteria in one hour in time-kill assays. We found that colistin promoted intracellular accumulation of equisetin in colistin-resistant E. coli based on LC-MS/MS analysis. Interestingly, equisetin boosted ROS accumulation in E. coli in the presence of colistin. Moreover, we found that equisetin and colistin lost the synergistic effect in two LPS-deficient A. baumannii strains. These findings suggest that colistin destroys the hydrophobic barrier of Gram-negative bacteria, facilitating equisetin to enter the cell and exert its antibacterial effect. Lastly, equisetin restored the activity of colistin in a G. mellonella larvae infection model. Collectively, these results reveal that equisetin can potentiate colistin activity against MDR Gram-negative bacteria including colistin-resistant strains, providing an alternative approach to address Gram-negative pathogens associated with infections in clinics.

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