Integrated approach to evaluating the toxicity of novel cysteine-capped silver nanoparticles to Escherichia coli and Pseudomonas aeruginosa

The Analyst ◽  
2014 ◽  
Vol 139 (5) ◽  
pp. 954-963 ◽  
Author(s):  
John H. Priester ◽  
Aditi Singhal ◽  
Binghui Wu ◽  
Galen D. Stucky ◽  
Patricia A. Holden
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Bacterial Growth ◽  
Ag Nanoparticles ◽  
Cell Membranes ◽  
Integrated Approach ◽  
E Coli ◽  
Particle Dissolution ◽  
Measured Particle

The toxicity of cysteine capped Ag nanoparticles toE. coliandP. aeruginosawas evaluated using an integrated approach that measured particle dissolution, bacterial growth, and effects on cell membranes.

scholarly journals Bacterial plasma membrane is the main cellular target of silver nanoparticles in Escherichia coli and Pseudomonas aeruginosa

2018 ◽  
Author(s):  
Olesja M Bondarenko ◽  
Mariliis Sihtmäe ◽  
Julia Kuzmičiova ◽  
Lina Ragelienė ◽  
Anne Kahru ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Plasma Membrane ◽  
Antimicrobial Properties ◽  
Consumer Products ◽  
Minimal Bactericidal Concentration ◽  
Flow Cytometry Analysis ◽  
E Coli ◽  
Cellular Target

ABSTRACTSilver nanoparticles (AgNP) are widely used in consumer products, mostly due to their excellent antimicrobial properties. One of the well-established antibacterial mechanisms of AgNP is their efficient contact with bacteria and dissolution on cell membranes. To our knowledge, the primary mechanism of cell wall damage and the event(s) initiating bactericidal action of AgNP are not yet elucidated.In this study we used a combination of different assays to reveal the effect of AgNP on i) bacterial envelope in general, ii) outer membrane (OM) and iii) on plasma membrane (PM). We showed that bacterial PM was the main target of AgNP in Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. AgNP depolarized bacterial PM, induced the leakage of the intracellular K+, inhibited respiration and caused the depletion of the intracellular ATP. In contrast, AgNP had no significant effect on the bacterial OM. Most of the adverse effects on bacterial envelope and PM occurred within the seconds and in the concentration range of 7-160 μM AgNP, depending on the bacteria and assay used, while irreversible inhibition of bacterial growth (minimal bactericidal concentration after 1-h exposure of bacteria to AgNP) occurred at 40 μM AgNP for P. aeruginosa and at 320 μM AgNP for E. coli.Flow cytometry analysis showed that AgNP were binding to P. aeruginosa but not to E. coli cells and were found inside the P. aeruginosa cells. Taking into account that AgNP did not damage OM, we speculate that AgNP entered P. aeruginosa via specific mechanism, e.g., transport through porins.

scholarly journals Antibacterial Screening Activity of Several Sponges Against Staphylococcus aureus, Escherichia coli, Staphylococcus saprophyticus, dan Pseudomonas aeruginosa

2019 ◽  
Vol 7 (2) ◽  
pp. 455
Author(s):  
Deiske A. Sumilat
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Inhibition Zone ◽  
E Coli ◽  
Antibacterial Screening ◽  
Sponge Extract ◽  
Screening Activity

Sponge samples collected around Manado waters were obtained 30 species and their crude extracted have been tested in vitro for their activity in inhibiting bacterial growth. Based on the results of antibacterial screening in 30 sponge extracts, there were 23 sponge extracts which had bioactivity in inhibiting the growth of S. aureus, E. coli, S. saprophyticus and P. aeruginosa, Sponge extract No. 43 (of 30 sponge extracts tested) was the most active in inhibiting bacterial growth and had the widest inhibition zone diameter.Keywords: screening, sponge, crude extract, antibacterial, ManadoABSTRAKSampel spons dikoleksi di sekitar Perairan Manado sebanyak 30 jenis/spesies, dimana ekstrak kasarnya telah diuji secara in vitro aktivitasnya dalam menghambat pertumbuhan bakteri. Berdasarkan hasil skrining antibakteri pada 30 ekstrak spons didapatkan hasil ada 23 ekstrak spons yang mempunyai bioaktivitas dalam menghambat pertumbuhan bakteri S. aureus, E. coli, S. saprophyticus dan P. aeruginosa, Ekstrak spons No. 3 (dari 30 ekstrak spons yang diuji) adalah yang paling aktif dalam menghambat pertumbuhan bakteri dan memiliki diameter zona hambat yang paling lebar.Kata kunci: skrining, spons, ekstrak kasar, antibakteri, Manado

scholarly journals Mutant Analysis Shows that Alanine Racemases from Pseudomonas aeruginosa and Escherichia coli Are Dimeric

2002 ◽  
Vol 184 (15) ◽  
pp. 4321-4325 ◽  
Author(s):  
Ulrich Strych ◽  
Michael J. Benedik
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Dominant Negative ◽  
Double Mutation ◽  
Present Evidence ◽  
Mutant Analysis ◽  
E Coli

ABSTRACT Alanine racemases are ubiquitous prokaryotic enzymes providing the essential peptidoglycan precursor d-alanine. We present evidence that the enzymes from Pseudomonas aeruginosa and Escherichia coli function exclusively as homodimers. Moreover, we demonstrate that expression of a K35A Y235A double mutation of dadX in E. coli suppresses bacterial growth in a dominant negative fashion.

Антимікробна резистентність провідних збудників інфекцій сечових шляхів у Києві (Україна)

2017 ◽  
Vol 1 (2) ◽  
pp. 48-60
Author(s):  
A.G. Salmanov ◽  
A.V. Rudenko
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
Klebsiella Oxytoca ◽  
Enterobacter Aerogenes ◽  
Enterobacter Cloacae ◽  
Proteus Vulgaris ◽  
Providencia Rettgeri ◽  
E Coli

Мета роботи — вивчити резистентність до антибіотиків бактеріальних збудників інфекцій сечових шляхів (ІСШ), виділених у пацієнтів урологічного стаціонару в м. Києві. Матеріали і методи. Досліджено 1612 штамів бактерій, виділених із сечі хворих з ІСШ (цистит, уретрит, пієлонефрит), госпіталізованих в урологічне відділення ДУ «Інститут урології НАМН України» у м. Києві протягом 2016 р. Серед пацієнтів переважали жінки — 1201 (74,5 %). Вік хворих становив від 17 до 74 років. Для збору даних використано медичну документацію лікарні. Мікробіологічні дослідження виконано у лабораторії мікробіології ДУ «Інститут урології НАМН України». Аналізували результати культурального дослідження зразків сечі, зібраних за наявності клінічних ознак ІСШ. Дослідження клінічного матеріалу та інтерпретацію отриманих результатів проводили загальноприйнятими методами. Вивчено чутливість уропатогенів до 31 антибіотика дискодифузійним методом відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)). Результати та обговорення. Аналіз мікробного спектра сечі виявив домінування серед уропатогенів штамів Escherichia coli (32,0 %), Enterococcus faecalis (19,5 %), Klebsiella pneumoniae (10,9 %), Staphylococcus epidermidis (8,9 %), S. haemolyticus (6,5 %) та Pseudomonas aeruginosa (6,4 %). Частка Enterococcus faecium, Enterobacter aerogenes і Streptococcus viridans становила відповідно 2,5, 2,2 і 1,6 %, Enterobacter cloacae, Klebsiella oxytoca, Acinetobacter baumannii, Proteus vulgaris та Providencia rettgeri — менше 1,0 %. У більшості випадків (69,7 %) мікроорганізми виділено у монокультурі, у решті випадків — у мікробних асоціа- ціях. Високу резистентність до тестованих антибіотиків виявили штами E. aerogenes (45,1 %), E. cloacae (45,7 %), E. faecium (40,9 %), E. faecalis (40,7 %), E. coli (39,9 %), P. aeruginosa (34,0 %), K. pneumoniae (28,6 %). Найбільш активними до уропатогенів були іміпенем (E. coli — 87,6 %, P. aeruginosa — 75,7 %, E. cloacae — 67,3 %, E. aerogenes — 72,6 %, K. pneumoniae — 93,2 %), меропенем (E. coli — 89,1 %, P. aeruginosa — 76,7 %, K. pneumoniae — 82,6 %), лефлоцин (E. coli — 74,5 %, ентерококи — 78,7 %, P. aeruginosa — 76,7 %, E. cloacae — 73,9 %, E. aerogenes — 80,4 %, K. pneumoniae — 83,5 %), амоксицилін/клавуланат (ентерококи — 84,6 %), фурагін (ентерококи — 82,6 %), цефоперазон (K. pneumoniae — 89,2 %, P. aeruginosa — 73,8 %), цефтріаксон (K. pneumoniae — 80,1 %). Висновки. Антибіотикорезистентність збудників ІСШ — важлива терапевтична проблема. Найбільшою активністю до уропатогенів характеризуються іміпенем, меропенем, лефлоцин, амоксицилін/ клавуланат, фурагін, цефоперазон, цефтріаксон, які можна розглядати як препарат вибору для призначення стартової терапії ІСШ. Необхідно здійснювати постійний моніторинг за резистентністю до дії антибіотиків. Політику використання антибіотиків у кожному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів.

Antimicrobial Activity of Silver Nanoparticles Prepared Under an Ultrasonic Field

2011 ◽  
Vol 4 (3) ◽  
pp. 1491-1496
Author(s):  
Umadevi M ◽  
Rani T ◽  
Balakrishnan T ◽  
Ramanibai R
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Reduction Method ◽  
Therapeutic Potential ◽  
Chemical Reduction ◽  
Ultrasonic Field ◽  
Great Promise ◽  
Chemical Reduction Method ◽  
E Coli

Nanotechnology has great promise for improving the therapeutic potential of medicinal molecules and related agents. In this study, silver nanoparticles of different sizes were synthesized in an ultrasonic field using the chemical reduction method with sodium borohydride as a reducing agent. The size effect of silver nanoparticles on antimicrobial activity were tested against the microorganisms Staphylococcus aureus (MTCC No. 96), Bacillus subtilis (MTCC No. 441), Streptococcus mutans (MTCC No. 497), Escherichia coli (MTCC No. 739) and Pseudomonas aeruginosa (MTCC No. 1934). The results shows that B. subtilis, and E. coli were more sensitive to silver nanoparticles and its size, indicating the superior antimicrobial efficacy of silver nanoparticles. 

scholarly journals Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abdulkader Masri ◽  
Naveed Ahmed Khan ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Ayaz Anwar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Neonatal Meningitis ◽  
E Coli ◽  
Drug Candidates ◽  
Metabolic Genes ◽  
Genetic Mechanisms ◽  
Cell Stress Response

Abstract Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.

scholarly journals High-density transposon libraries utilising outward-oriented promoters identify mechanisms of action and resistance to antimicrobials

2020 ◽  
Vol 367 (22) ◽  
Author(s):  
Chris Coward ◽  
Gopujara Dharmalingham ◽  
Omar Abdulle ◽  
Tim Avis ◽  
Stephan Beisken ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Selective Advantage ◽  
Mechanisms Of Action ◽  
Over Expression ◽  
E Coli ◽  
Synthase Inhibitor ◽  
Established Technique ◽  
Bacterial Transposon

ABSTRACT The use of bacterial transposon mutant libraries in phenotypic screens is a well-established technique for determining which genes are essential or advantageous for growth in conditions of interest. Standard, inactivating, transposon libraries cannot give direct information about genes whose over-expression gives a selective advantage. We report the development of a system wherein outward-oriented promoters are included in mini-transposons, generation of transposon mutant libraries in Escherichia coli and Pseudomonas aeruginosa and their use to probe genes important for growth under selection with the antimicrobial fosfomycin, and a recently-developed leucyl-tRNA synthase inhibitor. In addition to the identification of known mechanisms of action and resistance, we identify the carbon–phosphorous lyase complex as a potential resistance liability for fosfomycin in E. coli and P. aeruginosa. The use of this technology can facilitate the development of novel mechanism-of-action antimicrobials that are urgently required to combat the increasing threat worldwide from antimicrobial-resistant pathogenic bacteria.

scholarly journals Fabrication of a Novel AgBr/Ag2MoO4@InVO4 Composite with Excellent Visible Light Photocatalytic Property for Antibacterial Use

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1541
Author(s):  
Jie Zhang ◽  
Jia Wang ◽  
Qingjun Zhu ◽  
Binbin Zhang ◽  
Huihui Xu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Degradation Rate ◽  
Photocatalytic Property ◽  
Photocatalytic Reaction ◽  
Composite Photocatalyst ◽  
E Coli ◽  
Radical Trapping ◽  
Visible Light Photocatalytic

A novel AgBr/Ag2MoO4@InVO4 composite photocatalyst with different heterojunction structures was successfully constructed by compounding InVO4 with Ag2MoO4 and AgBr. According to the degradation, antibacterial and free radical trapping data, the photocatalytic antibacterial and antifouling activities of AgBr/Ag2MoO4@InVO4 composite were evaluated, and the corresponding photocatalytic reaction mechanism was proposed. Adding AgBr/Ag2MoO4@InVO4 composite, the degradation rate of ciprofloxacin (CIP) achieved 95.5% within 120 min. At the same time, the antibacterial rates of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) achieved 99.99%. The AgBr/Ag2MoO4@InVO4 composite photocatalyst showed promising usage in photocatalytic antibacterial and purification areas.

scholarly journals Estudio fitoquímico y actividad antimicrobiana de plantas medicinales empleadas para el control de infecciones urinarias

2021 ◽  
Vol 16 (1) ◽  
pp. 43-56
Author(s):  
Lida Vanessa Hernández Moreno ◽  
Ludy Cristina Pabón Baquero ◽  
Patricia Hernández-Rodríguez
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Zingiber Officinale ◽  
Taraxacum Officinale ◽  
Portulaca Oleracea ◽  
Uncaria Tomentosa ◽  
E Coli ◽  
Anthoxanthum Odoratum ◽  
Parietaria Officinalis

Las enfermedades infecciosas han sido un desafío para la humanidad. A pesar de los avances en la ciencia, aún muchas infecciones no tienen tratamientos efectivos o los microorganismos han generado resistencia a los antibióticos, de manera que las plantas medicinales son una alternativa de tratamiento y reducción de la resistencia. El objetivo de este estudio fue realizar un análisis fitoquímico preliminar y evaluar la actividad antimicrobiana de doce extractos etanólicos deplantas empleadas en la medicina tradicional colombiana como control de infecciones urinarias (IU). Las especies Anthoxanthum odoratum (grama), Urera caracasana (ortigón), Equisetum bogotenses (cola de caballo), Parietaria officinalis (parietaria), Achyrocline bogotensis (vira vira), Kohleria hirsuta (caracola), Taraxacum officinale (diente de león), Sedum praealtum (siempre viva), Portulaca oleracea (verdolaga), Petroselinum sativum (perejil), Zingiber officinale (jengibre) y Uncaria tomentosa (uña de gato) fueron adquiridas en la plaza de mercado Soacha (Cundinamarca) y sometidas a maceración con etanol a temperatura ambiente. La actividad antimicrobiana se evaluó por difusión en agar, microdilución en placa y bioautografía frente a Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) y Pseudomonas aeruginosa (ATCC 9027). Se determino que S. aureus y P. aeruginosa presentaron inhibición frente a cinco extractos en los tres métodos realizados, mientras que E. coli no fue inhibida por ningún extracto. Se estableció mediante bioautografía con reveladores específicos que los esteroides y/o triterpenoides, fenoles y flavonoides son los posibles metabolitos responsables de la actividad. Este tipo de investigaciones propicia estudios orientados al aislamiento de principios activos con utilidad en la elaboración de medicamentos para tratar IU.

scholarly journals Antibiotic Susceptibility and Genotype Patterns of Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa Isolated from Urinary Tract Infected Patients

2010 ◽  
Vol 59 (3) ◽  
pp. 207-212 ◽  
Author(s):  
M.I. ABOU-DOBARA ◽  
M.A. DEYAB ◽  
E.M. ELSAWY ◽  
H.H. MOHAMED
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Urinary Tract ◽  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Random Amplified Polymorphic Dna ◽  
Test Methods ◽  
Klebsiella Pneumonia ◽  
E Coli ◽  
Rapd Pcr

Thirty nine isolates of Escherichia coli, twenty two isolates of Klebsiella pneumoniae and sixteen isolates of Pseudomonas aeruginosa isolated from urinary tract infected patients were analyzed by antimicrobial susceptibility typing and random amplified polymorphic DNA (RAPD)-PCR. Antibiotic susceptibility testing was carried out by microdilution and E Test methods. From the antibiotic susceptibility, ten patterns were recorded (four for E. coli, three for K. pneumoniae and three for P. aeruginosa respectively). Furthermore, genotyping showed seventeen RAPD patterns (seven for E. coli, five for K. pneumoniae and five for P. aeruginosa respectively). In this study, differentiation of strains of E. coli, K. pneumoniae and P. aeruginosa from nosocomial infection was possible with the use of RAPD.

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