scholarly journals Antibacterial Activity of Non-Cytotoxic, Amino Acid-Modified Polycationic Dendrimers against Pseudomonas aeruginosa and Other Non-Fermenting Gram-Negative Bacteria

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1818 ◽  
Author(s):  
Anna Maria Schito ◽  
Silvana Alfei
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Eukaryotic Cells ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Resistance Rates ◽  
New Compounds

Due to the rapid increase of antimicrobial resistance with ensuring therapeutic failures, the purpose of this study was to identify novel synthetic molecules as alternatives to conventional available, but presently ineffective antibiotics. Variously structured cationic dendrimers previously reported have provided promising outcomes. However, the problem of their cytotoxicity towards eukaryotic cells has not been completely overcome. We have now investigated the antibacterial activities of three not cytotoxic cationic dendrimers (G5Ds: G5H, G5K, and G5HK) against several multidrug-resistant (MDR) clinical strains. All G5Ds displayed remarkable activity against MDR non-fermenting Gram-negative species such as P. aeruginosa, S. maltophilia, and A. baumannii (MICs = 0.5–33.2 µM). In particular, very low MIC values (0.5–2.1 µM) were observed for G5K, which proved to be more active than the potent colistin (2.1 versus 3.19 µM) against P. aeruginosa. Concerning its mechanism of action, in time-killing and turbidimetric studies, G5K displayed a rapid non-lytic bactericidal activity. Considering the absence of cytotoxicity of these new compounds and their potency, comparable or even higher than that provided by the dendrimers previously reported, G5Ds may be proposed as promising novel antibacterial agents capable of overcoming the alarming resistance rates of several nosocomial non-fermenting Gram-negative pathogens.

Antibacterial Activity and Chemical Composition of the Essential Oil of Grammosciadium platycarpum Boiss. from Iran

2005 ◽  
Vol 60 (1-2) ◽  
pp. 30-34 ◽  
Author(s):  
Ali Sonboli ◽  
Fereshteh Eftekhar ◽  
Morteza Yousefzadi ◽  
Mohammad Reza Kanani
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Chemical Composition ◽  
Essential Oil ◽  
Essential Oils ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Two Samples

The chemical composition of the essential oils obtained from two samples (GP1 and GP2) of Grammosciadium platycarpum Boiss. was analyzed by GC and GC-MS. The analysis of the oils resulted in the identification of twenty-two constituents. Linalool (79.0% - GP1, 81.8% - GP2) and limonene (10.0%, 5.8%) were found to be the major components, respectively. The in vitro antibacterial activities of these oils and their main compounds against seven Gram-positive and Gram-negative bacteria were investigated. The results exhibited that the total oils and their major components possess strong to moderate activities against all the tested bacteria except for Pseudomonas aeruginosa.

scholarly journals 5-Bromo-1-(4-chlorobenzyl)-1H-indole-2-carboxamides as new potent antibacterial agents

2018 ◽  
Vol 24 (6) ◽  
pp. 327-332 ◽  
Author(s):  
Yogesh D. Mane ◽  
Smita S. Patil ◽  
Dhanraj O. Biradar ◽  
Bhimrao C. Khade
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Internal Standards ◽  
Gram Negative ◽  
E Coli ◽  
High Antibacterial Activity

Abstract Ten 5-bromoindole-2-carboxamides were synthesized, characterized and evaluated for antibacterial activity against pathogenic Gram-negative bacteria Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Salmonella Typhi using gentamicin and ciprofloxacin as internal standards. Compounds 7a–c, 7g and 7h exhibit high antibacterial activity with a minimum inhibitory concentration (MIC) of 0.35–1.25 μg/mL. Compounds 7a–c exhibit antibacterial activities that are higher than those of the standards against E. coli and P. aeruginosa.

scholarly journals Antibacterial and Cytotoxic Activities of the Sesquiterpene Lactones Cnicin and Onopordopicrin

2011 ◽  
Vol 6 (2) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Sandra M. Bach ◽  
Mario A. Fortuna ◽  
Rodgoun Attarian ◽  
Juliana T. de Trimarco ◽  
César A. N. Catalán ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Sesquiterpene Lactones ◽  
Antibacterial Activities ◽  
Chloroform Extract ◽  
Cytotoxic Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
High Cytotoxicity

The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.

scholarly journals Pseudomonas aeruginosa Contact-Dependent Growth Inhibition Plays Dual Role in Host-Pathogen Interactions

mSphere ◽  
2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Jeffrey A. Melvin ◽  
Jordan R. Gaston ◽  
Shawn N. Phillips ◽  
Michael J. Springer ◽  
Christopher W. Marshall ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acute Infection ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Microbial Pathogenesis ◽  
Host Pathogen Interactions ◽  
Gram Negative ◽  
Content Type ◽  
Disease Outcomes ◽  
Host Pathogen

ABSTRACT How bacteria compete and communicate with each other is an increasingly recognized aspect of microbial pathogenesis with a major impact on disease outcomes. Gram-negative bacteria have recently been shown to employ a contact-dependent toxin-antitoxin system to achieve both competition and regulation of their physiology. Here, we show that this system is vital for virulence in acute infection as well as for establishment of chronic infection in the multidrug-resistant pathogen Pseudomonas aeruginosa. Greater understanding of the mechanisms underlying bacterial virulence and infection is important for the development of effective therapeutics in the era of increasing antimicrobial resistance. Microorganisms exist in a diverse ecosystem and have evolved many different mechanisms for sensing and influencing the polymicrobial environment around them, utilizing both diffusible and contact-dependent signals. Contact-dependent growth inhibition (CDI) is one such communication system employed by Gram-negative bacteria. In addition to CDI mediation of growth inhibition, recent studies have demonstrated CDI-mediated control of communal behaviors such as biofilm formation. We postulated that CDI may therefore play an active role in host-pathogen interactions, allowing invading strains to establish themselves at polymicrobial mucosal interfaces through competitive interactions while simultaneously facilitating pathogenic capabilities via CDI-mediated signaling. Here, we show that Pseudomonas aeruginosa produces two CDI systems capable of mediating competition under conditions of growth on a surface or in liquid. Furthermore, we demonstrated a novel role for these systems in contributing to virulence in acute infection models, likely via posttranscriptional regulation of beneficial behaviors. While we did not observe any role for the P. aeruginosa CDI systems in biofilm biogenesis, we did identify for the first time robust CDI-mediated competition during interaction with a mammalian host using a model of chronic respiratory tract infection, as well as evidence that CDI expression is maintained in chronic lung infections. These findings reveal a previously unappreciated role for CDI in host-pathogen interactions and emphasize their importance during infection. IMPORTANCE How bacteria compete and communicate with each other is an increasingly recognized aspect of microbial pathogenesis with a major impact on disease outcomes. Gram-negative bacteria have recently been shown to employ a contact-dependent toxin-antitoxin system to achieve both competition and regulation of their physiology. Here, we show that this system is vital for virulence in acute infection as well as for establishment of chronic infection in the multidrug-resistant pathogen Pseudomonas aeruginosa. Greater understanding of the mechanisms underlying bacterial virulence and infection is important for the development of effective therapeutics in the era of increasing antimicrobial resistance.

scholarly journals Antibiotic Resistant Bacterial Isolates from Captive Green Turtles andIn VitroSensitivity to Bacteriophages

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Alessandro Delli Paoli Carini ◽  
Ellen Ariel ◽  
Jacqueline Picard ◽  
Lisa Elliott
Keyword(s):  
Rapid Evolution ◽  
Chelonia Mydas ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Green Turtles ◽  
Resistant Genes ◽  
Resistance Rates

This study aimed to test multidrug resistant isolates from hospitalised green turtles(Chelonia mydas)and their environment in North Queensland, Australia, forin vitrosusceptibility to bacteriophages. Seventy-one Gram-negative bacteria were isolated from green turtle eye swabs and water samples. Broth microdilution tests were used to determine antibiotic susceptibility. All isolates were resistant to at least two antibiotics, with 24% being resistant to seven of the eight antibiotics. Highest resistance rates were detected to enrofloxacin (77%) and ampicillin (69.2%). More than 50% resistance was also found to amoxicillin/clavulanic acid (62.5%), ceftiofur (53.8%), and erythromycin (53.3%). All the enriched phage filtrate mixtures resulted in the lysis of one or more of the multidrug resistant bacteria, includingVibrio harveyiandV. parahaemolyticus. These results indicate that antibiotic resistance is common in Gram-negative bacteria isolated from hospitalised sea turtles and their marine environment in North Queensland, supporting global concern over the rapid evolution of multidrug resistant genes in the environment. Using virulent bacteriophages as antibiotic alternatives would not only be beneficial to turtle health but also prevent further addition of multidrug resistant genes to coastal waters.

scholarly journals Biological activity of manganese(i) tricarbonyl complexes on multidrug-resistant Gram-negative bacteria: From functional studies to in vivo activity in Galleria mellonella

Metallomics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2033-2042 ◽  
Author(s):  
Paul Güntzel ◽  
Christoph Nagel ◽  
Jeanette Weigelt ◽  
Jono W. Betts ◽  
Calum A. Pattrick ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Biological Activity ◽  
Galleria Mellonella ◽  
Atp Release ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Bacterial Clearance ◽  
Gram Negative ◽  
Functional Studies

Antibacterial activity of four Mn(CO)3 complexes on multidrug-resistant clinical isolates of A. baumannii and P. aeruginosa correlated with lipophilicity and increase in ATP release. Absence of host toxicity in G. mellonella was combined with effective bacterial clearance.

scholarly journals Pathogenicity Genomic Island-Associated CrpP-Like Fluoroquinolone-Modifying Enzymes among Pseudomonas aeruginosa Clinical Isolates in Europe

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
José Manuel Ortiz de la Rosa ◽  
Patrice Nordmann ◽  
Laurent Poirel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Genomic Island ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Genomic Islands ◽  
Clinical Isolates ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
Genes Encoding

ABSTRACT Many transferable quinolone resistance mechanisms have been identified in Gram-negative bacteria. The plasmid-encoded 65-amino-acid-long ciprofloxacin-modifying enzyme CrpP was recently identified in Pseudomonas aeruginosa isolates. We analyzed a collection of 100 clonally unrelated and multidrug-resistant P. aeruginosa clinical isolates, among which 46 were positive for crpP-like genes, encoding five CrpP variants conferring variable levels of reduced susceptibility to fluoroquinolones. These crpP-like genes were chromosomally located as part of pathogenicity genomic islands.

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.

Facile and Novel Synthesis of Spiky Gold Nanoparticles as an Efficient Antimicrobial Agent against Pseudomonas Aeruginosa

2021 ◽  
Vol 24 ◽  
Author(s):  
Farooq Aziz ◽  
Muhammad Rashid ◽  
Mubashar Rehman ◽  
Muhammad Rafique ◽  
Muhammad Imran
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gold Nanoparticles ◽  
Biomedical Applications ◽  
Antibacterial Agents ◽  
Reduction Method ◽  
Surface Plasmon Resonance Peak ◽  
Gram Negative Bacteria ◽  
Plasmon Resonance Peak ◽  
Gram Negative ◽  
Novel Synthesis

Aims: The study aims to develop advanced antibacterial agents as nanoparticles instead of antibiotics due to the emergence of antimicrobial resistance. Background: Pseudomonas aeruginosa is capable of causing many diseases, including severe bacterial pneumonia. There is a need for an efficient antibacterial agent to kill these pathogens. Objective: The objective of the study is to synthesize advanced antibacterial agents as nanoparticles for biomedical applications that can play a vital role in killing Gram-negative bacteria (Pseudomonas aeruginosa). Method: A novel fabricated growth of hydrophilic spiky gold nanoparticles (SGNPs) via reduction method is reported. Results: The surface plasmon resonance peak of the synthesized SGNPs was tuned under the near-infrared range. The SGNPs have anisotropic and spiky morphology with 68 nm size and -58 mV surface charge. They are pure, possessing adsorption similar to the organic material. Pseudomonas aeruginosa treated with synthesized SGNPs showed 60% bacterial death at the concentration of 100 μM. Conclusion: This work consists of the novel synthesis of SGNPs via a safe and simple reduction method. The synthesized SGNPs exhibit strong antibacterial activity against the Gram-negative bacteria Pseudomonas aeruginosa measured using a microplate assay test. The result showed that these SGNPs are ideal for biomedical applications.

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