scholarly journals Antibacterial Activity of Fluorobenzoylthiosemicarbazides and Their Cyclic Analogues with 1,2,4-Triazole Scaffold

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 170
Author(s):  
Urszula Kosikowska ◽  
Monika Wujec ◽  
Nazar Trotsko ◽  
Wojciech Płonka ◽  
Piotr Paneth ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Resistant Bacteria ◽  
Binding Affinities ◽  
Substitution Pattern ◽  
Minimal Inhibitory Concentrations ◽  
Gram Positive Bacteria ◽  
Structure Activity ◽  
Drug Resistant Bacteria ◽  
Reference Strains

The development of drug-resistant bacteria is currently one of the major challenges in medicine. Therefore, the discovery of novel lead structures for the design of antibacterial drugs is urgently needed. In this structure–activity relationship study, a library of ortho-, meta-, and para-fluorobenzoylthiosemicarbazides, and their cyclic analogues with 1,2,4-triazole scaffold, was created and tested for antibacterial activity against Gram-positive bacteria strains. While all tested 1,2,4-triazoles were devoid of potent activity, the antibacterial response of the thiosemicarbazides was highly dependent on substitution pattern at the N4 aryl position. The optimum activity for these compounds was found for trifluoromethyl derivatives such as 15a, 15b, and 16b, which were active against both the reference strains panel, and pathogenic methicillin-sensitive and methicillin-resistant Staphylococcus aureus clinical isolates at minimal inhibitory concentrations (MICs) ranging from 7.82 to 31.25 μg/mL. Based on the binding affinities obtained from docking, the conclusion can be reached that fluorobenzoylthiosemicarbazides can be considered as potential allosteric d-alanyl-d-alanine ligase inhibitors.

scholarly journals Nanoparticles Functionalized with Ampicillin Destroy Multiple-Antibiotic-Resistant Isolates of Pseudomonas aeruginosa and Enterobacter aerogenes and Methicillin-Resistant Staphylococcus aureus

2012 ◽  
Vol 78 (8) ◽  
pp. 2768-2774 ◽  
Author(s):  
Ashley N. Brown ◽  
Kathryn Smith ◽  
Tova A. Samuels ◽  
Jiangrui Lu ◽  
Sherine O. Obare ◽  
...  
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Enterobacter Aerogenes ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Gram Positive Bacteria ◽  
Drug Resistant Bacteria ◽  
Multiple Drug Resistant

ABSTRACTWe show here that silver nanoparticles (AgNP) were intrinsically antibacterial, whereas gold nanoparticles (AuNP) were antimicrobial only when ampicillin was bound to their surfaces. Both AuNP and AgNP functionalized with ampicillin were effective broad-spectrum bactericides against Gram-negative and Gram-positive bacteria. Most importantly, when AuNP and AgNP were functionalized with ampicillin they became potent bactericidal agents with unique properties that subverted antibiotic resistance mechanisms of multiple-drug-resistant bacteria.

Moxifloxacin derivatives with potential antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA)

2021 ◽  
Vol 21 ◽  
Author(s):  
Rongxing Chen ◽  
Huarui Xue ◽  
Yazhou Xu ◽  
Tianwei Ma ◽  
Yuan Liu ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Topoisomerase Iv ◽  
Methicillin Resistant ◽  
Structure Activity ◽  
Drug Resistant Bacteria ◽  
Mrsa Strains

Background: Methicillin-resistant S. aureus (MRSA) has already tormented humanity and the environment for a long time and is responsible for many difficult-to-treat infections. Unfortunately, there are limited therapeutic options, and MRSA isolates with complete resistance to vancomycin, the first-line drug for the treatment of MRSA infections, have already emerged in recent years. Moxifloxacin retained activity against mutant bacterial strains with various levels of fluoroquinolones resistance and had a lower potential to select for resistant mutants. Isatin is a versatile structure, and its derivatives are potent inhibitors of many enzymes and receptors. The fluoroquinolone-isatin derivatives demonstrated excellent antibacterial activity against both drug-sensitive and drug-resistant organisms. The structure-activity relationship elucidated that incorporation of 1,2,3-triazole moiety into the C-7 position of fluoroquinolone skeleton was favorable to the antibacterial activity. Accordingly, fluoroquinolone derivatives with isatin and 1,2,3-triazole fragments at the side chain on the C-7 position are promising candidates to fight against drug-resistant bacteria. Objective: To explore more active moxifloxacin derivatives to fight against MRSA and enrich the structure-activity relationships. Methods: The synthesized moxifloxacin derivatives 7a-i and 14a-f were evaluated for their antibacterial activity against a panel of MRSA strains by means of standard two-fold serial dilution method. Results: The majority of the synthesized moxifloxacin derivatives were active against most of the tested MRSA strains with MIC values in a range of 1 to 64 μg/mL. The mechanistic investigations revealed that topoisomerase IV was one of the targets for antibacterial activity. Conclusion: These derivatives are useful scaffolds for the development of novel topoisomerase IV inhibitors.

scholarly journals A novel bis(pyrazolyl)methane compound as a potential agent against Gram-positive bacteria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pedro Seguí ◽  
John J. Aguilera-Correa ◽  
Elena Domínguez-Jurado ◽  
Christian M. Sánchez-López ◽  
Ramón Pérez-Tanoira ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Inhibitory Effect ◽  
Eukaryotic Cell ◽  
Liver Carcinoma ◽  
Gram Positive ◽  
Minimal Inhibitory Concentrations ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Therapeutic Compounds ◽  
Toxic Concentrations

AbstractThis study was designed to propose alternative therapeutic compounds to fight against bacterial pathogens. Thus, a library of nitrogen-based compounds bis(triazolyl)methane (1T–7T) and bis(pyrazolyl)methane (1P–11P) was synthesised following previously reported methodologies and their antibacterial activity was tested using the collection strains of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Moreover, the novel compound 2P was fully characterized by IR, UV–Vis and NMR spectroscopy. To evaluate antibacterial activity, minimal inhibitory concentrations (MICs), minimal bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and minimum biofilm eradication concentrations (MBECs) assays were carried out at different concentrations (2–2000 µg/mL). The MTT assay and Resazurin viability assays were performed in both human liver carcinoma HepG2 and human colorectal adenocarcinoma Caco-2 cell lines at 48 h. Of all the synthesised compounds, 2P had an inhibitory effect on Gram-positive strains, especially against S. aureus. The MIC and MBC of 2P were 62.5 and 2000 µg/mL against S. aureus, and 250 and 2000 µg/mL against E. faecalis, respectively. However, these values were > 2000 µg/mL against E. coli and P. aeruginosa. In addition, the MBICs and MBECs of 2P against S. aureus were 125 and > 2000 µg/mL, respectively, whereas these values were > 2000 µg/mL against E. faecalis, E. coli, and P. aeruginosa. On the other hand, concentrations up to 250 µg/mL of 2P were non-toxic doses for eukaryotic cell cultures. Thus, according to the obtained results, the 2P nitrogen-based compound showed a promising anti-Gram-positive effect (especially against S. aureus) both on planktonic state and biofilm, at non-toxic concentrations.

scholarly journals Novel Seleno- and Thio-Urea Containing Dihydropyrrol-2-One Analogues as Antibacterial Agents

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 321
Author(s):  
Shekh Sabir ◽  
Tsz Tin Yu ◽  
Rajesh Kuppusamy ◽  
Basmah Almohaywi ◽  
George Iskander ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Positive Bacterium ◽  
Quorum Sensing Inhibition ◽  
Drug Resistant Bacteria

The quorum sensing (QS) system in multi-drug-resistant bacteria such as P. aeruginosa is primarily responsible for the development of antibiotic resistance and is considered an attractive target for antimicrobial drug discovery. In this study, we synthesised a series of novel selenourea and thiourea-containing dihydropyrrol-2-one (DHP) analogues as LasR antagonists. The selenium DHP derivatives displayed significantly better quorum-sensing inhibition (QSI) activities than the corresponding sulphur analogues. The most potent analogue 3e efficiently inhibited the las QS system by 81% at 125 µM and 53% at 31 µM. Additionally, all the compounds were screened for their minimum inhibitory concentration (MIC) against the Gram-positive bacterium S. aureus, and interestingly, only the selenium analogues showed antibacterial activity, with 3c and 3e being the most potent with a MIC of 15.6 µM.

scholarly journals Synergistic Antibacterial Activity of Lantana camara L., Parthenium hysterophorus L., Cannabis sativa L. and Justicia adhatoda L. Leaves Extract against Procured Multi-drug Resistant Bacteria In Vitro

2021 ◽  
pp. 34-40
Author(s):  
Jyoti Chandola ◽  
Pooja Singh ◽  
Rishabh Garg ◽  
Narotam Sharma
Keyword(s):  
Antibacterial Activity ◽  
Medicinal Plants ◽  
Cannabis Sativa ◽  
Lantana Camara ◽  
Parthenium Hysterophorus ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Weed Plants ◽  
Justicia Adhatoda

The scientific study of this research has been focused on synergistic antibacterial activity of two weed plants, Lantana camara L., Parthenium hysterophorus L. alongwith two medicinal plants, Cannabis sativa L., Justicia adhatoda L. against multi- drug resistant (MDR) bacteria. Dried leaf powders of the plants were extracted using air-dried method followed by the ethanol- solvent extraction method for the crude extract of the leaves. The crude extracts were tested for antibacterial activity against three MDR bacteria, that is, one Gram positive bacteria- Staphylococcus aureus and two Gram negative bacteria- Escherichia coli and Proteus mirabilis. Out of 18 antibiotics tested against procured bacteria, Staphylococcus aureus was resistant to 10 out of 10 tested antibiotics, Escherichia coli was resistant to 4 out of 12 tested antibiotics and Proteus mirabilis was resistant to 9 out of 10 tested antibiotics. The tested weed plants and the medicinal plants when combined together showed more zone of inhibition against multidrug resistant bacteria ( Two combinations of phytochemicals Lantana camara, Cannabis sativa and Lantana camara, Cannabis sativa, Justicia adhatoda, Parthenium hysterophorus showed maximum zones of inhibition, that is, 30 mm) as compared to when these plants were tested solitarily, showing pronounced antibacterial activity. These findings showed that the antibacterial activity enhanced when they were combined together and this potential could be used against various infectious diseases with more research and modification in this area. Weed plants also holds as much importance as the medicinal plants although not to that extent, but they clearly inhibit the growth of bacteria and this property of weeds along with the medicinal plants holds a promising future in treating many diseases caused by multi-drug resistant bacteria on the pharmaceutical level.

scholarly journals Antibacterial Activity of Prismatomeris tetrandra K. Schum Root Extract against Antibiotic Resistance Bacteria

2018 ◽  
Vol 16 (5) ◽  
pp. 341-348
Author(s):  
On-Anong SOMSAP
Keyword(s):  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Culture Broth ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Root Extract ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Gram Positive Bacteria ◽  
Colony Forming Units

Antibiotic resistance bacteria has become an increasing problem now today due to many factors. This study investigates the efficacy of Prismatomeris tetrandra K. Schum root extract as a new source of antibacterial activity for antibiotic resistant bacteria using agar well diffusion method. The results showed that S. aureus TISTR517 exhibited more sensitivity to P. tetrandra K. Schum root extract than other Gram-positive bacteria indicator strains. On the other hand, Gram-negative bacteria exhibited resistance to P. tetrandra K. Schum root extract. The study further showed the activity between P. tetrandra K. Schum root extract and gentamycin (10 µg), it revealed that MRSA142 was resistant to gentamycin (10µg) but sensitive to P. tetrandra K. Schum root extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was evaluated by using S. aureus TISTR517 and MRSA142 as indicator strains. The MIC value was 0.59 mg/mL and 1.17 mg/mL for S. aureus TISTR517 and MRSA142, respectively. MBC assay demonstrated that the MBC value was 9.75 mg/mL and 150 mg/mL for S. aureus TISTR517 and MRSA142 respectively. The mode of action was investigated with the presence of P. tetrandra K. Schum root extract in the culture broth. The action of P. tetrandra K. Schum root extract was revealed of bacteriostatic activity due to the Optical density (OD) at 600 nm and Colony-Forming Units (CFU) of indicator strains were continuously decreased.

scholarly journals Quorum Sensing Inhibition in Chromobacterium violaceum, Antibacterial Activity and GC-MS Analysis of Centaurea praecox (Oliv. & Hiern) Extracts

2020 ◽  
Vol 9 (4) ◽  
pp. 1569-1577
Keyword(s):  
Antibacterial Activity ◽  
Quorum Sensing ◽  
Research Strategy ◽  
Chromobacterium Violaceum ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Control Drug ◽  
Ms Analysis ◽  
Drug Resistant Bacteria

The quorum sensing (QS) mechanism has become a viable research strategy for the discovery of plant-derived anti-virulent agents to control drug-resistant bacteria. The increasing incidences of drug-resistant bacteria and the effort to curb it necessitate this study. We investigated the QS inhibitory potential of Centaurea praecox extracts on Chromobacterium violaceum (CV), antibacterial activity, and determination of chemical composition using GC-MS. C. praecox was subjected to sequential extraction using hexane (HEX), dichloromethane (DCM), ethyl acetate (EA), ethanol (ET), and aqueous (AQ) solvents. The extracts were subsequently evaluated for antibacterial activity using disc diffusion and QS violacein inhibition using spectrophotometry. The antibacterial effects of the extracts were moderate on gram-positive bacteria at 4 mg/mL in the order: HEX >EA >DCM >ET =AQ. However, the DCM extract demonstrated the most effective violacein inhibition of ≥80% at 0.3 mg/mL. QS violacein inhibitions were generally found to be concentration-dependent in the order: DCM >EA >HEX >ET =AQ with efficacies of ≥ 90% inhibition at ≥ 0.6 mg/mL. GC-MS analysis on the most potent DCM extract revealed N-vinylmethanimine, N-ethyl formamide, and propanamide among components identified. We concluded that C. praecox DCM extract contains bioactive chemicals as QS inhibitors and potential anti-virulent agents capable of combating the pathogenicity of drug-resistant bacteria in vivo.

scholarly journals Targeted-Antibacterial-Plasmids (TAPs) combining conjugation and CRISPR/Cas systems achieve strain-specific antibacterial activity

2020 ◽  
Author(s):  
Audrey Reuter ◽  
Cécile Hilpert ◽  
Annick Dedieu-Berne ◽  
Sophie Lematre ◽  
Erwan Gueguen ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Carbapenem Resistance ◽  
Double Strand Breaks ◽  
Resistant Bacteria ◽  
Innovative Strategy ◽  
Strand Breaks ◽  
Drug Resistant Bacteria

AbstractThe global emergence of drug-resistant bacteria leads to the loss of efficacy of our antibiotics arsenal and severely limits the success of currently available treatments. Here, we developed an innovative strategy based on Targeted-Antibacterial-Plasmids (TAPs) that use bacterial conjugation to deliver CRISPR/Cas systems exerting a strain-specific antibacterial activity. TAPs are highly versatile as they can be directed against any specific genomic or plasmid DNA using the custom algorithm (CSTB) that identifies appropriate targeting spacer sequences. We demonstrate the ability of TAPs to induce strain-selective killing by introducing lethal double strand breaks (DSBs) into the targeted genomes. TAPs directed against a plasmid-born carbapenem resistance gene efficiently resensitise the strain to the drug. This work represents an essential step towards the development of an alternative to antibiotic treatments, which could be used for in situ microbiota modification to eradicate targeted resistant and/or pathogenic bacteria without affecting other non-targeted bacterial species.

Vacancy‐Induced Antibacterial Activity of XS 2– y Quantum Dots against Drug‐Resistant Bacteria for Treatment of Bacterial Keratitis

Small ◽  
2020 ◽  
Vol 16 (42) ◽  
pp. 2004677
Author(s):  
Huiyuan Li ◽  
Xiao Wang ◽  
Xiaofei Zhao ◽  
Guanhua Li ◽  
Fengyan Pei ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Antibacterial Activity ◽  
Resistant Bacteria ◽  
Bacterial Keratitis ◽  
Drug Resistant ◽  
Drug Resistant Bacteria

scholarly journals Identification of A Novel Antibacterial Peptide from Atlantic Mackerel belonging to the GAPDH-Related Antimicrobial Family and Its In Vitro Digestibility

Marine Drugs ◽  
2019 ◽  
Vol 17 (7) ◽  
pp. 413 ◽  
Author(s):  
Clément Offret ◽  
Ismaïl Fliss ◽  
Laurent Bazinet ◽  
André Marette ◽  
Lucie Beaulieu
Keyword(s):  
Antibacterial Activity ◽  
Solid Phase ◽  
Bioactive Molecules ◽  
Peptide Sequence ◽  
In Vitro Digestibility ◽  
Biotechnological Potential ◽  
Minimal Inhibitory Concentrations ◽  
Atlantic Mackerel ◽  
Gram Positive Bacteria

The Atlantic mackerel, Scomber scombrus, is one of the most fished species in the world, but it is still largely used for low-value products, such as bait; mainly for crustacean fishery. This resource could be transformed into products of high value and may offer new opportunities for the discovery of bioactive molecules. Mackerel hydrolysate was investigated to discover antibacterial peptides with biotechnological potential. The proteolytic process generated a hydrolysate composed of 96% proteinaceous compounds with molecular weight lower than 7 kDa. From the whole hydrolysate, antibacterial activity was detected against both Gram-negative and Gram-positive bacteria. After solid phase extraction, purification of the active fraction led to the identification of 4 peptide sequences by mass spectrometry. The peptide sequence N-KVEIVAINDPFIDL-C, called Atlantic Mackerel GAPDH-related peptide (AMGAP), was selected for chemical synthesis to confirm the antibacterial activity and to evaluate its stability through in vitro digestibility. Minimal inhibitory concentrations of AMGAP revealed that Listeria strains were the most sensitive, suggesting potential as food-preservative to prevent bacterial growth. In addition, in vitro digestibility experiments found rapid (after 20 min) and early digestibility (stomach). This study highlights the biotechnological potential of mackerel hydrolysate due to the presence of the antibacterial AMGAP peptide.

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