scholarly journals The Analogs of Temporin-GHa Exhibit a Broader Spectrum of Antimicrobial Activity and a Stronger Antibiofilm Potential against Staphylococcus aureus

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4173 ◽  
Author(s):  
Zhipeng Xie ◽  
Hanqi Wei ◽  
Jiahui Meng ◽  
Tong Cheng ◽  
Yanting Song ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Therapeutic Potential ◽  
Membrane Damage ◽  
Therapeutic Index ◽  
Antibacterial Activities ◽  
Therapeutic Window ◽  
Resistant Bacteria ◽  
Cell Selectivity ◽  
Initial Adhesion

The abuse of antibiotics has led to the emergence of multidrug-resistant bacteria, which is becoming a serious worldwide problem people have to face. In our previous study, temporin-GHa (GHa) cloned from Hylarana guentheri showed antimicrobial activity against Gram-positive bacteria. In order to improve its therapeutic potential, we used a template-based and a database-assisted design to obtain three derived peptides by replacing the histidine at both ends of GHa with lysine, which exhibited faster and stronger bactericidal activity and a broader spectrum than the parent peptide. GHaK and GHa4K targeted to the bacterial membrane to exert their antibacterial activities at a faster membrane damage rate. The derived peptides inhibited the initial adhesion and the formation of Staphylococcus aureus biofilms, and eradicated the mature biofilms, which indicated that the derived peptides effectively penetrated the biofilm and killed bacteria. The therapeutic index (TI) and cell selectivity index (CSI) of the derived peptides increased significantly, which means a broader therapeutic window of the derived peptides. The derived peptides with improved activity and cell selectivity have the potential to be the promising candidates for the treatment of S. aureus infections. Our research also provides new insights into the design and development of antimicrobial peptides.

scholarly journals Hypochlorite-Activated Fluorescence Emission and Antibacterial Activities of Imidazole Derivatives for Biological Applications

2021 ◽  
Vol 9 ◽  
Author(s):  
Thanh Chung Pham ◽  
Van-Nghia Nguyen ◽  
Yeonghwan Choi ◽  
Dongwon Kim ◽  
Ok-Sang Jung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Antibacterial Activities ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Fluorogenic Probe ◽  
High Fluorescence

The ability to detect hypochlorite (HOCl/ClO−) in vivo is of great importance to identify and visualize infection. Here, we report the use of imidazoline-2-thione (R1SR2) probes, which act to both sense ClO− and kill bacteria. The N2C=S moieties can recognize ClO− among various typical reactive oxygen species (ROS) and turn into imidazolium moieties (R1IR2) via desulfurization. This was observed through UV–vis absorption and fluorescence emission spectroscopy, with a high fluorescence emission quantum yield (ՓF = 43–99%) and large Stokes shift (∆v∼115 nm). Furthermore, the DIM probe, which was prepared by treating the DSM probe with ClO−, also displayed antibacterial efficacy toward not only Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) but also methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum ß-lactamase–producing Escherichia coli (ESBL-EC), that is, antibiotic-resistant bacteria. These results suggest that the DSM probe has great potential to carry out the dual roles of a fluorogenic probe and killer of bacteria.

scholarly journals Changes in the Ultrastructure of Staphylococcus aureus Treated with Cationic Peptides and Chlorhexidine

2020 ◽  
Vol 8 (12) ◽  
pp. 1991
Author(s):  
Alina Grigor’eva ◽  
Alevtina Bardasheva ◽  
Anastasiya Tupitsyna ◽  
Nariman Amirkhanov ◽  
Nina Tikunova ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Membrane ◽  
Antimicrobial Peptides ◽  
Membrane Damage ◽  
Observation Time ◽  
Resistant Bacteria ◽  
Cationic Peptides ◽  
Bacterial Cells ◽  
Cell Membrane Damage

Antimicrobial peptides, including synthetic ones, are becoming increasingly important as a promising tool to fight multidrug-resistant bacteria. We examined the effect of cationic peptides H2N-Arg9-Phe2-C(O)NH2 and H2N-(Lys-Phe-Phe)3-Lys-C(O)NH2 on Staphylococcus aureus, which remains one of the most harmful pathogens. Antiseptic chlorhexidine served as reference preparation. We studied viability of S. aureus and examined its ultrastructure under treatment with 100 µM of R9F2 or (KFF)3K peptides or chlorhexidine using transmission electron microscopy of ultrathin sections. Bacterial cells were sampled as kinetic series starting from 1 min up to 4 h of treatment with preparations. Both peptides caused clearly visible damage of bacteria cell membrane within 1 min. Incubation of S. aureus with R9F2 or (KFF)3K peptides led to cell wall thinning, loss of cytoplasm structure, formation of mesosome-derived multimembrane structures and “decorated fibers” derived from DNA chains. The effect of R9F2 peptides on S. aureus was more severe than the effect of (KFF)3K peptides. Chlorhexidine heavily damaged the bacteria cell wall, in particular in areas of septa formation, while cytoplasm kept its structure within the observation time. Our study showed that cell membrane damage is critical for S. aureus viability; however, we believe that cell wall disorders should also be taken into account when analyzing the effects of the mechanisms of action of antimicrobial peptides (AMPs).

Synthesis and antimicrobial activity of 4-trifluoromethylpyridine nucleosides

2017 ◽  
Vol 23 (3) ◽  
pp. 197-203 ◽  
Author(s):  
Shaikha S. Alneyadi ◽  
Anas A. Abdulqader ◽  
Alaa A. Salem ◽  
Ibrahim M. Abdou
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Stenotrophomonas Maltophilia ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Nucleoside Analogues ◽  
Reference Drug ◽  
Minimum Inhibitory Concentrations

Abstract4-Trifluoromethylpyridine derivatives 4–8 represent good candidates for the discovery of new antibacterial agents. Fluorinated pyridine nucleosides 4–7 and non-nucleoside analogues 8a,b were synthesized and evaluated for their antibacterial activities against Staphylococcus aureus, Bacillus infantis, Escherichia coli and Stenotrophomonas maltophilia. The minimum inhibitory concentrations (MICs) of the new nucleosides 4–7 range from 1.3 to 4.9 μg/mL and MICs of fluoroaryl derivatives 8a,b are in the range of 1.8–5.5 μg/mL. Activity of amoxicillin, the reference drug, is 1.0–2.0 μg/mL under similar conditions.

scholarly journals Antioxidant and Antibacterial Activities of the Essential Oil of Moroccan Tetraclinis articulata (Vahl) Masters

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Halima Rabib ◽  
Chaimaa Elagdi ◽  
Mohammed Hsaine ◽  
Hassan Fougrach ◽  
Tayeb Koussa ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Essential Oil ◽  
Antioxidant Properties ◽  
Antibacterial Activities ◽  
Bornyl Acetate ◽  
Radical Trap ◽  
Tetraclinis Articulata

The purpose of this study is to evaluate and compare the antioxidant and antibacterial activities of essential oil isolated from Tetraclinis articulata (Vahl) leaves, Masters originating in Morocco (Benslimane Region, Atlantic-influenced plain). The analysis of the major compounds of essential oil was performed by gas chromatography and mass spectrometry, and this oil is dominated by bornyl acetate (35.05%), camphor (11.17%), and α-pinene (10.84%). The antioxidant properties were evaluated by the test of the radical trap 2,2-diphényl-1-picrylhydrazyl (DPPH), and the antimicrobial activity of T. articulata essential oil was tested against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli which have been inhibited from the 25 μg/mL.

scholarly journals AKTIVITAS ANTIMIKROBA EKSTRAK DAUN JAMBU BIJI DARI BEBERAPA KULTIVAR TERHADAP Staphylococcus aureus ATCC 25923 DENGAN HOLE-PLATE DIFFUSION METHOD

2003 ◽  
Vol 9 (1) ◽  
pp. 49-51
Author(s):  
Farida Lanawati Darsono ◽  
Stephanie Devi Artemisia
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Traditional Medicine ◽  
Tween 80 ◽  
Antibacterial Activities ◽  
Psidium Guajava ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Gram Positive Bacteria ◽  
Activity Test

A study has been performed on the antimicrobial activities of jambu biji (Psidium guajava Linn) leaves from several cultivars (red, white and yellow cultivar) against Staphylococcus aureus ATCC 25923 representing the Gram positive bacteria. The reason for conducting this research is that the leaves of jambu biji are frequently used in traditional medicine as a remedy against diarrhoea. The hole-plate diffusion method was used for conducting the antimicrobial activity test with antibiotics (Ampicilline trihidrat) as reference standards. The extracts of jambu biji for each cultivar were obtained by reflux with ethanol 96 percent. The concentrations of the extracts applied to the holes were 10 percent, 20 percent, and 30 percent w/v, the extracts were reconstituted with tween 80 and ethanol 96 percent. Based on the result of the study, it can be concluded that the extract of jambu biji from each cultivar with the concentration of 10 percent, 20 percent, and 30 percent w/v showed antibacterial activities against Staphylococcus aureus ATCC 25923. The result obtained statictically evaluated using Anava Factorial 3x3 and furthery tested for significancy (a = 0.05). Based on the results of study, it can be concluded that the extract of jambu biji leaves from red cultivar, white cultivar and yellow cultivar showed antibacterial activities against Staphylococcus aureus ATCC 25923.

scholarly journals THE ANTIBACTERIAL EFFICACY OF ETHANOL EXTRACTS OBTAINED FROM LEAVES OF SOME THYMUS SPECIES (LAMIACEAE) AGAINST STAPHYLOCOCCUS AUREUS SUBSP. AUREUS STRAIN

2021 ◽  
pp. 18-29
Author(s):  
N. Kurhaluk ◽  
H. Tkachenko ◽  
V. Honcharenko ◽  
V. Nachychko ◽  
A. Prokopiv ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activities ◽  
Aureus Strain ◽  
Future Research ◽  
Antibacterial Efficacy ◽  
Disk Diffusion Assay ◽  
The Difference ◽  
Plant Families ◽  
Ethanol Extracts

A convincing number of investigations that indicate that thymol with other metabolites exhibited potent antimicrobial, antifungal, antibacterial, and antiparasitic properties prompted us to verify the antibacterial efficacy of four species and one interspecific hybrid of the Thymus genus collected in the western part of Ukraine against Staphylococcus aureus subsp. aureus (ATCC® 29213™) strain. Considering the points highlighted above and based on previous results obtained in our laboratory, in the current study, we decided to evaluate the antimicrobial efficacy of five ethanol extracts obtained from leaves of Thymus representatives against Staphylococcus aureus subsp. aureus (ATCC® 29213™) strain. Fresh leaves were washed, weighed, crushed, and homogenized in 96 % ethanol (in proportion 1:19) at room temperature. The extracts were then filtered and investigated for their antimicrobial activity. Antimicrobial activity was determined using the agar disk diffusion assay. The ethanol extracts obtained from leaves of Thymus plants showed different antibacterial activities against Staphylococcus aureus subsp. aureus (ATCC® 29213™) strain. The antibacterial activity of extracts was greatest for Th. serpyllum followed by Th. pannonicus followed by Th. pulegioides, Th. alpestris, and then by Th. x porcii. Since the antibacterial effectiveness of medicinal plants varies dramatically depending on the phytochemical characteristics of plant families and subfamilies, it is not surprising to note the difference in this efficacy even when using samples taken from the same plant, but from two different regions. The antimicrobial activity of the crude ethanol extracts obtained from leaves of Thymus plants may be attributed to specific compounds or a combination of compounds. The present study lays the basis for future research, to validate the possible use of Thymus species as a candidate in the treatment of infections caused by Staphylococcus aureusin medicine and veterinary.

scholarly journals Oxidative Stress and Antimicrobial Activity of Chromium(III) and Ruthenium(II) Complexes onStaphylococcus aureusandEscherichia coli

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina L. Páez ◽  
Claudia M. Bazán ◽  
María E. Bongiovanni ◽  
Judith Toneatto ◽  
Inés Albesa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Diimine Ligands

The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat previously easily treatable infections. The main aim of this work was to establish the potential of the syntheticα-diimine chromium(III) and ruthenium(II) complexes (where theα-diimine ligands are bpy = 2,2-bipyridine, phen = 1,10-phenanthroline, and dppz = dipyrido[3,2-a:2′,3′-c]-phenazine) like [Cr(phen)3]3+, [Cr(phen)2(dppz)]3+, [Ru(phen)3]2+, and [Ru(bpy)3]2+as antibacterial agents by generating oxidative stress. The [Cr(phen)3]3+and [Cr(phen)2(dppz)]3+complexes showed activity against Gram positive and Gram negative bacteria with minimum inhibitory concentrations (MICs) ranging from 0.125 μg/mL to 1 μg/mL, while [Ru(phen)3]2+and [Ru(bpy)3]2+do not exhibit antimicrobial activity against the two bacterial genera studied at the concentration range used. When ciprofloxacin was combined with [Cr(phen)3]3+for the inhibition ofStaphylococcus aureusandEscherichia coli, an important synergistic effect was observed, FIC 0.066 forS. aureusand FIC 0.064 forE. coli. The work described here shows that chromium(III) complexes are bactericidal forS. aureusandE. coli. Our results indicate thatα-diimine chromium(III) complexes may be interesting to open new paths for metallodrug chemotherapy against different bacterial genera since some of these complexes have been found to exhibit remarkable antibacterial activities.

scholarly journals Comparative Antibacterial Efficacy of Vitellaria paradoxa (Shea Butter Tree) Extracts Against Some Clinical Bacterial Isolates

2015 ◽  
Vol 7 (3) ◽  
pp. 264-268 ◽  
Author(s):  
Kamoldeen Abiodun AJIJOLAKEWU ◽  
Fola Jose AWARUN
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Klebsiella Pneumoniae ◽  
Bacterial Pathogens ◽  
Stem Bark ◽  
Antibacterial Activities ◽  
Shea Butter ◽  
Vitellaria Paradoxa ◽  
Ethanolic Extracts

The antibacterial activities of the ethanolic extracts of seed, leaf and stem bark of Vitellaria paradoxa were investigated. The extracts were tested against three clinical bacterial pathogens, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae using the agar diffusion and the broth dilution techniques. Ethanolic extracts of the plant parts showed activity against all the bacterial pathogens tested. At the highest extract concentration (200 mg/ml), the leaf extract exhibited the highest antimicrobial activity, while no activity was detected at the lowest concentration (3.13 mg/ml) against the tested isolates. Escherichia coli and Staphylococcus aureus were more susceptible to all extracts of V. paradoxa, while Klebsiella pneumoniae showed the least sensitivity. The efficacy of ethanolic extracts of Vitellaria paradoxa was compared to a commercial antibiotic streptomycin. There were differences in the minimum inhibitory concentration (MIC) of all the Vitellaria paradoxa ethanolic extracts with respect to the type of organism. All extracts exhibited bacteriostatic effects against the tested organisms at the experimented concentrations. Qualitative phytochemical screening of the extracts revealed the presence of saponins, tannins and alkaloids as the active principles of Vitellaria paradoxa's antimicrobial activity. V. paradoxa could be used as a potential source of antibiotic substance for a drug development.

scholarly journals All d-Lysine Analogues of the Antimicrobial Peptide HPA3NT3-A2 Increased Serum Stability and without Drug Resistance

2020 ◽  
Vol 21 (16) ◽  
pp. 5632
Author(s):  
Jong-Kook Lee ◽  
Yoonkyung Park
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antimicrobial Peptide ◽  
Proteolytic Enzymes ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Peptide Bonds ◽  
Drug Resistant Bacteria ◽  
Antibiotic Drugs ◽  
Strong Antimicrobial Activity

Novel antibiotic drugs are urgently needed because of the increase in drug-resistant bacteria. The use of antimicrobial peptides has been suggested to replace antibiotics as they have strong antimicrobial activity and can be extracted from living organisms such as insects, marine organisms, and mammals. HPA3NT3-A2 ([Ala1,8] HPA3NT3) is an antimicrobial peptide that is an analogue of the HP (2–20) peptide derived from Helicobacter pylori ribosomal protein L1. Although this peptide was shown to have strong antimicrobial activity against drug-resistant bacteria, it also showed lower toxicity against sheep red blood cells (RBCs) and HaCaT cells compared to HPA3NT3. The l-Lys residues of HPA3NT3-A2 was substituted with d-Lys residues (HPA3NT3-A2D; [d-Lys2,5,6,9,10,15] HPA3NT3-A2) to prevent the cleavage of peptide bonds by proteolytic enzymes under physiological conditions. This peptide showed an increased half-life and maintained its antimicrobial activity in the serum against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (pathogen). Furthermore, the antimicrobial activity of HPA3NT3-A2D was not significantly affected in the presence of mono- or divalent ions (Na+, Mg2+, Ca2+). Finally, l- or d-HPA3NT3-A2 peptides exhibited the strongest antimicrobial activity against antibiotic-resistant bacteria and failed to induce resistance in Staphylococcus aureus after 12 passages.

scholarly journals Intravitreal Injection of the Chimeric Phage Endolysin Ply187 Protects Mice from Staphylococcus aureus Endophthalmitis

2014 ◽  
Vol 58 (8) ◽  
pp. 4621-4629 ◽  
Author(s):  
Pawan Kumar Singh ◽  
David M. Donovan ◽  
Ashok Kumar
Keyword(s):  
Staphylococcus Aureus ◽  
Intravitreal Injection ◽  
Structural Integrity ◽  
Therapeutic Potential ◽  
Neutrophil Infiltration ◽  
Multidrug Resistant ◽  
Lytic Enzyme ◽  
Resistant Bacteria ◽  
Content Type ◽  
Mrsa Strains

ABSTRACTThe treatment of endophthalmitis is becoming very challenging due to the emergence of multidrug-resistant bacteria. Hence, the development of novel therapeutic alternatives for ocular use is essential. Here, we evaluated the therapeutic potential of Ply187AN-KSH3b, a chimeric phage endolysin derived from the Ply187 prophage, in a mouse model ofStaphylococcus aureusendophthalmitis. Our data showed that the chimeric Ply187 endolysin exhibited strong antimicrobial activity against both methicillin-sensitiveS. aureusand methicillin-resistantS. aureus(MRSA) strains, as evidenced by MIC determinations, reductions in turbidity, and disruption of biofilms. Moreover, exposure ofS. aureusto Ply187 for up to 10 generations did not lead to resistance development. The intravitreal injection of chimeric Ply187 (at 6 or 12 h postinfection) significantly improved the outcome of endophthalmitis, preserved retinal structural integrity, and maintained visual function as assessed by electroretinogram analysis. Furthermore, phage lysin treatment significantly reduced the bacterial burden and the levels of inflammatory cytokines and neutrophil infiltration in the eyes. These results indicate that the intravitreal administration of a phage lytic enzyme attenuates the development of bacterial endophthalmitis in mice. To the best of our knowledge, this is the first study demonstrating the therapeutic use of phage-based antimicrobials in ocular infections.

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