scholarly journals Antibacterial Properties of Nanosilver PLLA Fibrous Membranes

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Lin Li ◽  
Yi Li ◽  
Jiashen Li ◽  
Lei Yao ◽  
Arthur F. T. Mak ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Antibacterial Properties ◽  
Weight Ratio ◽  
Antibacterial Effects ◽  
E Coli ◽  
Fibrous Membranes ◽  
Composite Fibrous Membranes

Nanosilver has been studied as a valuable material for it strong antibacterial effects. In this study, we investigated the antibacterial properties of nano silver Poly-L-Lactic acid (Ag/PLLA) composite fibrous membranes. Ag/PLLA fibrous membranes were prepared with silver nanoparticles having weight ratio of silver nanoparticles to PLLA at 5% (w/w). In vitro antibacterial tests were performed usingEscherichia coli(E. coli) andStaphylococcus aureus(Staph.) to determine the antibacterial capability of the Ag/PLLA fibrous membranes. As the results suggested, Ag/PLLA fibrous membranes showed strong antibacterial properties. Thus, Ag/PLLA fibrous membrane can be used as an antibacterial scaffold for tissue engineering.

Evaluation of Antibacterial Properties of Leather Treated with Silver Nanoparticles

2013 ◽  
Vol 60 (1) ◽  
Author(s):  
Zohreh Majidnia ◽  
Ani Idris ◽  
Peiman Valipour
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Antibacterial Properties ◽  
Test Methods ◽  
Antibacterial Effects ◽  
E Coli ◽  
Leather Processing ◽  
Processing Step ◽  
Unpleasant Smell

Objektif kajian ini adalah untuk merawat kulit dengan nanopartikel perak untuk membangunkan ciri-ciri antibakteria di kulit. Aktiviti biologi ke atas kasut kulit menyebabkan pertumbuhan bakteria dan menyebabkan bau yang tidak menyenangkan. Nanopartikel perak telah diketahui mempunyai beberapa kesan antibakteria dan telah ditambah kepada minyak yang digunakan dalam langkah pemprosesan kulit. Sedikit nanopartikel perak (6 dan 8%v/v) telah dimasukkan ke dalam minyak dan ciri-ciri antibakteria telah dinilai menggunakan rendaman dan kaedah ujian kapasiti. Larutan bakteria, bersamaan kekeruhan McFarland piawai sebanyak 0.5 telah disediakan untuk staphylococcus aureus dan bakteria Escherichia coli. Hasil kajian menunjukkan bahawa ujian antimikrobial ke atas sampel yang mengandungi nanopartikel perak menunjukkan ciri-ciri antibakteria yang indikasi oleh Piawai Antarabangsa (ISO 22196) kelembutan penggantungan kurang dari 3x108 CFU/ml. Oleh itu kulit yang dirawat dengan nanopartikel perak mempunyai ciri-ciri antibakteria dengan kecenderungan untuk mengurangkan bau-bau tidak menyenangkan. Kata kunci: Kulit; sifat anti-bakteria; nanopartikel; perak The objective of this study is to treat leather with silver nanoparticles so as to develop antibacterial properties in the leather. The biological activity on leather shoes resulted in bacterial growth and caused the unpleasant smell. Silver nanoparticles have been known to possess some antibacterial effects and were added to the oil used in the leather processing step. A small amount of silver nanoparticles (6 and 8%v/v) were added to oil and its antibacterial properties have been evaluated using the immersion and capacity test methods. The bacteria suspension, a turbidity equivalent to a 0.5 McFarland standard was prepared for the S. aureus and E. coli bacteria. Results revealed that antimicrobial tests on samples containing silver nanoparticles showed suitable antibacterial properties indicated by the International Standard (ISO 22196) tenderness of suspension of less than 3x108 CFU/ml. Thus leather treated with silver nanoparticles has antibacterial properties with the tendency to reduce the unpleasant odors. Keywords: Leather; antibacterial properties; nanoparticle, silver

scholarly journals IN VITRO TESTING OF CLOVE EXTRACTS IN INHIBITING AND KILLING STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI

2021 ◽  
Vol 10 (1) ◽  
pp. 16-19
Author(s):  
Nadia Dwi Rahmawati ◽  
Tri Nur Kristina ◽  
Endang Sri Lestari ◽  
Hardian Hardian
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Skin Irritation ◽  
Antibacterial Properties ◽  
Control Group ◽  
Dilution Method ◽  
Control Group Design ◽  
E Coli ◽  
Clove Extract

Background: Diarrhea that could be caused by Staphylococcus aureus and Escherichia coli can be prevented by increasing hand hygiene using alcohol-based hand rub, but frequent use might cause skin irritation. Replacing alcohol with herbs could avoid this side effect. Cloves have been proved to have antibacterial properties. However, most researches used complex extraction methods that might not be applicable on a household scale.Objective: To prove that clove extracts have ability to inhibit and to kill S. aureus and E. coli.Methods: This is an experimental study by using post-test only control group design. Clove extract was obtained with simple aqueous maceration. Samples were Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 allocated into six groups: clove extracts at concentrations of 12.5%, 25%, 50%, 100% respectively; 70% alcohol as a positive control; and aquadest as a negative control. Each group was given 5 repetitions of intervention. MIC was measured with dilution method, while MBC with streak method. Negative controls were only used to monitor the quality of this work.Results: MIC of S. aureus was started at 50% concentration of clove extract, while MBC of S. aureus was started at 25 % concentration of the same extract. MIC and MBC of E. coli was both started at 25% concentration of clove extract. MIC and MBC of 100% concentration of clove extract were equal with 70% alcohol.Conclusion: Concentration of 100% clove extracts have similar ability with 70% alcohol to inhibit and to kill S. aureus and E. coli. Keywords: Clove Extracts, Escherichia coli, MBC, MIC, Staphylococcus aureus

Substituted 4-Formyl-2H-chromen-2-ones: Their Reaction with N-(2,3,4,6-Tetra-Oacetyl- β-D-galactopyranosyl)thiosemicarbazide, Antibacterial and Antifungal Activity of Their Thiosemicarbazone Products

2020 ◽  
Vol 24 (19) ◽  
pp. 2272-2282
Author(s):  
Vu Ngoc Toan ◽  
Nguyen Minh Tri ◽  
Nguyen Dinh Thanh
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Selenium Dioxide ◽  
Antibacterial And Antifungal Activity ◽  
E Coli ◽  
Antibacterial And Antifungal Activities ◽  
Alkyl Ethers ◽  
Antibacterial And Antifungal

Several 6- and 7-alkoxy-2-oxo-2H-chromene-4-carbaldehydes were prepared from corresponding alkyl ethers of 6- and 7-hydroxy-4-methyl-2-oxo-2H-chromen-2-ones by oxidation using selenium dioxide. 6- and 7-Alkoxy-4-methyl-2H-chromenes were obtained with yields of 57-85%. Corresponding 4-carbaldehyde derivatives were prepared with yields of 41-67%. Thiosemicarbazones of these aldehydes with D-galactose moiety were synthesized by reaction of these aldehydes with N-(2,3,4,6-tetra-O-acetyl-β-Dgalactopyranosyl) thiosemicarbazide with yields of 62-74%. These thiosemicarbazones were screened for their antibacterial and antifungal activities in vitro against bacteria, such as Staphylococcus aureus, Escherichia coli, and fungi, such as Aspergillus niger, Candida albicans. Several compounds exhibited strong inhibitory activity with MIC values of 0.78- 1.56 μM, including 8a (against S. aureus, E. coli, and C. albicans), 8d (against E. coli and A. niger), 9a (against S. aureus), and 9c (against S. aureus and C. albicans).

scholarly journals Differential behaviors of Staphylococcus aureus and Escherichia coli type II DNA topoisomerases.

1996 ◽  
Vol 40 (12) ◽  
pp. 2714-2720 ◽  
Author(s):  
F Blanche ◽  
B Cameron ◽  
F X Bernard ◽  
L Maton ◽  
B Manse ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Strong Support ◽  
Dna Gyrase ◽  
Dna Supercoiling ◽  
Type Ii ◽  
Topoisomerase Iv ◽  
E Coli ◽  
Dna Relaxation

Staphylococcus aureus gyrA and gyrB genes encoding DNA gyrase subunits were cloned and coexpressed in Escherichia coli under the control of the T7 promoter-T7 RNA polymerase system, leading to soluble gyrase which was purified to homogeneity. Purified gyrase was catalytically indistinguishable from the gyrase purified from S. aureus and did not contain detectable amounts of topoisomerases from the E. coli host. Topoisomerase IV subunits GrlA and GrlB from S. aureus were also expressed in E. coli and were separately purified to apparent homogeneity. Topoisomerase IV, which was reconstituted by mixing equimolar amounts of GrlA and GrlB, had both ATP-dependent decatenation and DNA relaxation activities in vitro. This enzyme was more sensitive than gyrase to inhibition by typical fluoroquinolone antimicrobial agents such as ciprofloxacin or sparfloxacin, adding strong support to genetic studies which indicate that topoisomerase IV is the primary target of fluoroquinolones in S. aureus. The results obtained with ofloxacin suggest that this fluoroquinolone could also primarily target gyrase. No cleavable complex could be detected with S. aureus gyrase upon incubation with ciprofloxacin or sparfloxacin at concentrations which fully inhibit DNA supercoiling. This suggests that these drugs do not stabilize the open DNA-gyrase complex, at least under standard in vitro incubation conditions, but are more likely to interfere primarily with the DNA breakage step, contrary to what has been reported with E. coli gyrase. Both S. aureus gyrase-catalyzed DNA supercoiling and S. aureus topoisomerase IV-catalyzed decatenation were dramatically stimulated by potassium glutamate or aspartate (500- and 50-fold by 700 and 350 mM glutamate, respectively), whereas topoisomerase IV-dependent DNA relaxation was inhibited 3-fold by 350 mM glutamate. The relevance of the effect of dicarboxylic amino acids on the activities of type II topoisomerases is discussed with regard to the intracellular osmolite composition of S. aureus.

scholarly journals Evaluation du potentiel antimicrobien et de la toxicité des extraits de Jatropha multifida Linn, (Euphorbiaceae)

2020 ◽  
Vol 151 ◽  
pp. 15550-15558
Author(s):  
Amégninou Agban ◽  
Yao Hoekou ◽  
Passimna Pissang ◽  
Tchadjobo Tchacondo ◽  
Komlan Batawila
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Aqueous Extract ◽  
E Coli ◽  
Toxicological Studies ◽  
Jatropha Multifida

Objectif : L’objectif de ce travail était d’évaluer in vitro l’activité antimicrobienne des extraits de feuilles et tige de Jatropha multifida sur la croissance de Candida albicans, Escherichia coli et Staphylococcus aureus, puis d’évaluer in vivo la toxicité de cette plante. Méthodologie et résultats : Les méthodes de diffusion en milieu gélosé et de microdilution en milieu liquide ont été utilisées pour évaluer l’effet antimicrobien. Une étude en subaigüe était réalisée afin d’explorer les effets toxiques de l’extrait aqueux des feuilles. Les résultats des tests antimicrobiens montrent une activité des extraits de feuilles et tige de J. multifida sur la croissance des souches utilisées avec des diamètres de zones d’inhibition allant de 8 à 25 mm et des concentrations minimales inhibitrices (CMI) variant de 0,039 mg/mL à 1,25 mg/mL à l’exception des souches de E. coli qui sont résistantes aux extraits de la tige. L’administration en subaigüe de l’extrait aqueux des feuilles de J. multifida à la dose de 600 mg/kg entraîne une perte significative de poids chez les souris. Conclusion et applications des résultats : Les extraits aqueux, éthanolique et hydroéthanolique des feuilles et tige de J. multifida possèdent d’activité antimicrobienne et pourraient être utilisés dans le traitement des Candidoses à C. albicans et des infections à S. aureus. Mais l’essai de toxicité subaigüe montre que l’extrait aqueux de la plante serait toxique. Des études toxicologiques approfondies restent donc nécessaires sur ces extraits afin de mieux élucider leur inocuité. Mots-clés : Jatropha multifida, extraits de feuilles et de tige, activités antifongique et antibactérienne, toxicité. Agban et al., J. Appl. Biosci. 2020 Evaluation du potentiel antimicrobien et de la toxicité des extraits de Jatropha multifida Linn, (Euphorbiaceae) 15551 Evaluation of antimicrobial potential and toxicity of Jatropha multifida Linn, (Euphorbiaceae) extracts ABSTRACT Objective: The objective of this study was to evaluate in vitro the antimicrobial activity of leaves and stem of Jatropha multifida extracts against Candida albicans, Escherichia coli and Staphylococcus aureus, and then to evaluate in vivo the toxicity of this plant. Methodology and Results: The agar well-diffusion and the NCCLS broth microdilution methods were used to assess the antimicrobial effect. A subacute study was carried out to explore the toxic effects of the aqueous extract of the leaves. The results of the antimicrobial tests show an activity of the extracts of leaves and stems of J. multifida on the growth of the strains used with diameters of inhibitory zones ranging from 8 to 25 mm and minimum inhibitory concentrations (MIC) varying from 0.039 mg/mL to 1.25 mg/mL exception E. coli strains which are resistant to extracts from the stem. Subacute administration of the aqueous extract of the leaves of J. multifida at a dose of 600 mg/kg leads to a significant loss of weight in the mice. Conclusion and application of findings : The aqueous, ethanolic and hydroethanolic extracts of the leaves and stem of J. multifida have antimicrobial activity and could be used in the treatment of Candidiasis and bacterial infections due respectively to C. albicans and S. aureus. But the subacute toxicity test shows that the aqueous extract of the plant would be toxic. Extensive toxicological studies therefore remain necessary on these extracts in order to better elucidate their safety. Keywords: Jatropha multifida extracts of leaves and stem, antifungal and antibacterial activities, toxicity

scholarly journals Screening of Escherichia coli Species Biodiversity Reveals New Biofilm-Associated Antiadhesion Polysaccharides

mBio ◽  
2011 ◽  
Vol 2 (3) ◽  
Author(s):  
Olaya Rendueles ◽  
Laetitia Travier ◽  
Patricia Latour-Lambert ◽  
Thierry Fontaine ◽  
Julie Magnus ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Bacterial Adhesion ◽  
Bioactive Molecules ◽  
Bacterial Biofilms ◽  
Gram Positive ◽  
Content Type ◽  
E Coli ◽  
Species Biodiversity

ABSTRACTBacterial biofilms often form multispecies communities in which complex but ill-understood competition and cooperation interactions occur. In light of the profound physiological modifications associated with this lifestyle, we hypothesized that the biofilm environment might represent an untapped source of natural bioactive molecules interfering with bacterial adhesion or biofilm formation. We produced cell-free solutions extracted fromin vitromature biofilms formed by 122 naturalEscherichia coliisolates, and we screened these biofilm extracts for antiadhesion molecules active on a panel of Gram-positive and Gram-negative bacteria. Using this approach, we showed that 20% of the tested biofilm extracts contained molecules that antagonize bacterial growth or adhesion. We characterized a compound, produced by a commensal animalE. colistrain, for which activity is detected only in biofilm extract. Biochemical and genetic analyses showed that this compound corresponds to a new type of released high-molecular-weight polysaccharide whose biofilm-associated production is regulated by the RfaH protein. We demonstrated that the antiadhesion activity of this polysaccharide was restricted to Gram-positive bacteria and that its production reduced susceptibility to invasion and provided rapid exclusion ofStaphylococcus aureusfrom mixedE. coliandS. aureusbiofilms. Our results therefore demonstrate that biofilms contain molecules that contribute to the dynamics of mixed bacterial communities and that are not or only poorly detected in unconcentrated planktonic supernatants. Systematic identification of these compounds could lead to strategies that limit pathogen surface colonization and reduce the burden associated with the development of bacterial biofilms on medical devices.IMPORTANCEWe sought to demonstrate that bacterial biofilms are reservoirs for unknown molecules that antagonize bacterial adhesion. The use of natural strains representative ofEscherichia colispecies biodiversity showed that nonbiocidal antiadhesion polysaccharides are frequently found in mature biofilm extracts (bacterium-free suspensions which contain soluble molecules produced within the biofilm). Release of an antiadhesion polysaccharide confers a competitive advantage upon the producing strain against clinically relevant pathogens such asStaphylococcus aureus. Hence, exploring the biofilm environment provides a better understanding of bacterial interactions within complex communities and could lead to improved control of pathogen colonization.

scholarly journals Actividad antibacteriana in vitro de aceites esenciales de diferentes especies del género Citrus

2017 ◽  
Vol 46 (2) ◽  
Author(s):  
Miladys Esther Torrenegra Alarcón ◽  
Nerlis Paola Pájaro ◽  
Glicerio León Méndez
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
E Coli

Se evaluó la actividad antibacteriana in vitro de aceites esenciales de diferentes especiesdel género Citrus frente a cepas ATCC de Staphylococcus aureus, Staphylococcus epidermidis,Klebsiella pneumoniae, Pseudomonas aeruginosa y Escherichia coli, determinandola concentración mínima inhibitoria (CMI) y la concentración mínima bactericida(CMB). Las bacterias se replicaron en medios de agar y caldos específicos. Se determinóel momento de máxima densidad óptica (DO620) para emplearlo como tiempode incubación; luego se hicieron pruebas de evaluación de sensibilidad con la exposiciónde las cepas a concentraciones a 1000 g/mL del extracto en caldo. Para solubilizarse empleó dimetilsulfóxido (DMSO) al 1%. Posteriormente, se le determinó laconcentración mínima inhibitoria mediante metodologías de microdilución en caldoy la concentración mínima bactericida. Encontrándose una actividad de los aceitesesenciales del género Citrus, con valores de CMI ≥ 600 mg/mL frente a S. aureus,S. epidermidis, K. pneumoniae, P. aeruginosa y E. coli. En función a los resultados obtenidos,se concluye que las diferentes especies del género Citrus son consideradas comopromisorias para el control del componente bacteriano.

Note: Effect of Some Spice Extracts on Bacterial Inhibition

2003 ◽  
Vol 9 (5) ◽  
pp. 353-358 ◽  
Author(s):  
O. Sagdic ◽  
A. G. Karahan ◽  
M. Ozcan ◽  
G. Ozkan
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Yersinia Enterocolitica ◽  
Inhibition Zone ◽  
Bacterial Strains ◽  
Inhibitory Effects ◽  
Antibacterial Effects ◽  
E Coli ◽  
Inhibition Zones ◽  
Mrs Broth

Eighteen extracts of spices commonly consumed worldwide and grown naturally in Turkey were tested against twenty three bacterial strains to compare their antibacterial effects with eleven antibiotics. Eight pathogens and fifteen lactobacilli isolated from chick intestine were used as the test microorganisms. Pathogens (six different Staphylococcus aureus strains, Escherichia coli ATCC 25922 and Yersinia enterocolitica ATCC 1501) were grown in Nutrient broth and lactobacilli in MRS broth. Hop extracts formed inhibition zones against S. aureus strains of upto 36 mm. Inhibitory effects of hop extracts against S. aureuswere generally higher than that of erythromycin as antibiotic. Helichrysum compactum extract produced an inhibition zone of 23mm to E. coli ATCC 25922 and 26mm to Y. enterocolitica ATCC 1501. Helichrysum compactum extract inhibited the growth of Y. enterocolitica ATCC 1501 more than other spice extracts. While inhibition zones of these extracts against lactobacilli were found smaller than on S. aureus strains, inhibition zones of the same extracts against lactobacilli were found similar to those of E. coli ATCC 25922 and Y. enterocolitica ATCC 1501.

Rosemary and Tea Tree Essential Oils Exert Antibiofilm Activities In Vitro against Staphylococcus aureus and Escherichia coli

2020 ◽  
Vol 83 (7) ◽  
pp. 1261-1267
Author(s):  
TING LIU ◽  
JINGFAN WANG ◽  
XIAOMAN GONG ◽  
XIAOXIA WU ◽  
LIU LIU ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Essential Oil ◽  
Biofilm Formation ◽  
Gas Chromatography Mass Spectrometry ◽  
Tea Tree ◽  
E Coli ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACT The purpose of the present study was to determine the bioactive compounds in rosemary essential oil (REO) and tea tree essential oil (TEO) and to investigate their antibacterial and antibiofilm activities against Staphylococcus aureus and Escherichia coli in vitro. The MIC and MBC assays were performed to assess the antibacterial activity of these two EOs against S. aureus and E. coli with the broth microdilution method. A crystal violet assay was used to ascertain the effects of EOs on the biofilm formation of the test strains, and a tetrazolium bromide (MTT) assay was used to measure the level of inactivation of mature biofilms by EOs. Gas chromatography–mass spectrometry revealed 15 compounds in REO and 27 compounds in TEO, representing 97.78 and 98.13% of the total EO, respectively. Eucalyptol and α-pinene were found in high concentrations in REO, and the two major compounds in TEO were 4-terpineol and terpinolene. The MICs of REO for the two S. aureus and E. coli test strains were both 0.5 mg/mL, and the MICs of TEO for the two strains were both 0.25 mg/mL. Therefore, these EOs can significantly inhibit the formation of biofilms and induced morphological biofilm changes, as verified by scanning electron microscopy. Both EOs had destructive effects on the mature biofilm of the two test strains. TEO was more inhibitory than REO for biofilm formation by the two test strains. HIGHLIGHTS

scholarly journals Structure-activity relationships of 3-substituted-5,5- diphenylhydantoins as potential antiproliferative and antimicrobial agents

2011 ◽  
Vol 76 (12) ◽  
pp. 1597-1606 ◽  
Author(s):  
Nemanja Trisovic ◽  
Bojan Bozic ◽  
Ana Obradovic ◽  
Olgica Stefanovic ◽  
Snezana Markovic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Human Colon ◽  
Antibacterial Activities ◽  
E Coli ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Almost All

A series of twelve 3-substituted-5,5-diphenylhydantoins was synthesized, including some whose anticonvulsant activities have already been reported in the literature. Their antiproliferative activities against HCT-116 human colon carcinoma cells were evaluated to determine structure-activity relationships. Almost all of the compounds exhibited statistically significant antiproliferative effects at a concentration of 100 ?M, while the derivative bearing a benzyl group was active even at lower concentrations. Moreover, their in vitro antibacterial activities against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and clinical isolates of Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus were evaluated. Only the 3-iso-propyl and 3-benzyl derivatives showed weak antibacterial activities against the Gram-positive bacterium E. faecalis and the Gram-negative bacteria E. coli ATCC 25922 and E. coli.

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