Search results for "staphylococcus aureu"
showing 10 items of 298 documents
Dual Enzyme-Responsive Capsules of Hyaluronic Acid-block-Poly(Lactic Acid) for Sensing Bacterial Enzymes.
2015
The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA-block-PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme-responsive HYA-b-PLA is carried out by copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron…
Isolation, purification and antibacterial effects of fusaproliferin produced by Fusariumsubglutinans in submerged culture.
2009
To evaluate the fusaproliferin (FUS) production, Fusariumsubglutinans ITEM 2404 was grown in a liquid medium of potato being this mycotoxin purified by high-performance liquid chromatography (HPLC) with a C18 semipreparative column using a mobile phase of acetonitrile/H(2)O using gradient conditions. The purity of the fusaproliferin was verified by analytical HPLC, ultraviolet absorbance measurements, LC/MS-MS, (1)H NMR spectroscopy. The isolated FUS was shown to be free of impurities and can be used as a standard for routine analysis. The pure fusaproliferin was utilized to study the biological activity on Escherichiacoli and Staphylococcusaureus. This study demostred that FUS not showed s…
Inhalable polymer-glycerosomes as safe and effective carriers for rifampicin delivery to the lungs
2016
Rifampicin loaded glycerosomes, vesicles composed of phospholipids, glycerol and water, were combined with trimethyl chitosan chloride (TMC) to prepare TMC-glycerosomes or, alternatively, with sodium hyaluronate (HY) to obtain HY-glycerosomes. These new hybrid nanovesicles were tested as carriers for pulmonary delivery of rifampicin. Glycerosomes without polymers were also prepared and characterized. All vesicles were similar: they were spherical, multilamellar and able to incorporate good amount of rifampicin (EE%∼55%). The addition of the polymers to the formulations allowed an increase of mean diameter. All the glycerosomes, in particular HY-glycerosomes, were able to deliver the drug to…
Augu preparāta un antibakteriālo vielu sinerģiskā darbība
2020
Visā pasaulē arvien vairāk tiek runāts par dažādu mikroorganismu un to izraisīto infekciju ārstēšanas iespējām. Gan nozokomiālās infekcijas, gan sabiedrībā iegūtas infekcijas ir viens no lielākajiem draudiem sabiedrības veselībai. Šīs infekcijas ir viens no galvenajiem faktoriem jaunu antibakteriālo līdzekļu vai to kombināciju pētīšanai. Maģistra darba ietvaros tika izmantoti baktēriju izolāti, kuri iegūti no Latvijas Universitātes mikrobioloģijas kultūru kolekcijas. Darbā tika izmantoti divi Staphylococcus aureus celmi, meticilīna jutīgais un klīniskais celms, un 11 augu komponenšu preparāts AFI. Antibakteriālo līdzekļu efektivitāte tika pārbaudīta ar hinolonu grupas pretmikrobu līdzekli –…
Daļēji ar stronciju aizvietotu hidroksil-peroksiapatītu analītiska raksturošana un antibakteriālo īpašību izpēte
2018
Daļēji ar stronciju aizvietotu hidroksil-peroksiapatītu analītiska raksturošana un antibakteriālo īpašību izpēte. Valkovska V., darba vadītāja docente, Dr. chem. Osīte A. Maģistra darbs, 72 lappuses, 26 attēli, 15 tabulas, 126 literatūras avoti, 8 pielikumi. Latviešu valodā. Darbā ir apkopota informācija par hidroksilapatītu un hidroksil-peroksiapatītu iegūšanu, fizikālajām un ķīmiskajām īpašībām, izmantošanu, analīzes metodēm, kalcija fosfātu biomateriālu mikrobioloģiskajām īpašībām, to antibakteriālās aktivitātes un toksicitātes novērtēšanu, stabilo izotopu sastāvu bioloģiskajā apatītā. Eksperimentālajā daļā veiktas kalcija hidroksilapatīta un daļēji ar stronciju aizvietotu hidroksilapatī…
1,2,4-Oxadiazole topsentin analogs as staphylococcal biofilm inhibitors targeting the bacterial transpeptidase sortase A
2020
The inhibition or prevention of biofilm formation represents an emerging strategy in the war against antibiotic resistance, interfering with key players in bacterial virulence. This approach includes the inhibition of the catalytic activity of transpeptidase sortase A (Srt A), a membrane enzyme responsible for covalently attaching a wide variety of adhesive matrix molecules to the peptidoglycan cell wall in Gram-positive strains. A new series of seventeen 1,2,4-oxadiazole derivatives was efficiently synthesized and screened as potential new anti-virulence agents. The ability of inhibiting biofilm formation was evaluated against both Gram-positive and Gram-negative pathogens. Remarkably, all…
2,6-Disubstituted imidazo[2,1-b][1,3,4]thiadiazole derivatives as potent staphylococcal biofilm inhibitors.
2019
Abstract A class of 36 new 2-(6-phenylimidazo[2,-1-b][1,3,4]thiadiazol-2-yl)-1H-indoles was efficiently synthesized and evaluated for their anti-biofilm properties against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923, S. aureus ATCC 6538 and Staphylococcus epidermidis ATCC 12228, and the Gram-negative strains Pseudomonas aeruginosa ATCC 15442 and Escherichia coli ATCC 25922. Many of these new compounds, were able to inhibit biofilm formation of the tested staphylococcal strains showing BIC50 lower than 10 μg/ml. In particular, derivatives 9c and 9h showed remarkable anti-biofilm activity against S. aureus ATCC 25923 with BIC50 values of 0.5 and 0.8 μg/ml, r…
Epidemiology of intra-abdominal infection and sepsis in critically ill patients: "AbSeS", a multinational observational cohort study and ESICM Trials…
2019
Pardo-Oviedo, Juan Mauricio/0000-0003-0084-3449; Lopez-Delgado, Juan Carlos/0000-0003-3324-1129; Corradi, Francesco/0000-0002-5588-2608; De Backer, Daniel/0000-0001-9841-5762; POTA, VINCENZO/0000-0001-9999-3388; Tomescu, Dana/0000-0001-9673-5754; Sabetian, Golnar/0000-0001-8764-2150; Girardis, Massimo/0000-0002-2453-0829; Brazzi, Luca/0000-0001-7059-0622; Leone, Marc/0000-0002-3097-758X; Zabolotskikh, Igor Borisovich/0000-0002-3623-2546; De Lange, Dylan/0000-0002-0191-7270; ALMEKHLAFI, GHALEB A./0000-0002-0323-7025; Elke, Gunnar/0000-0002-4948-1605; Grigoras, Ioana/0000-0001-9412-9574; Czuczwar, Miroslaw/0000-0002-9025-6717; Nora, David/0000-0002-1133-7368; Masjedi, Mansoor/0000-0001-6175-9…
Distribution and kinetics of superantigen-induced cytokine gene expression in mouse spleen.
1993
The polyclonal stimulation of T cells by bacterial superantigens is involved in the pathogenesis of the toxic shock syndrome in certain staphylococcal and streptococcal infections. Here we describe the onset and kinetics of superantigen-induced cytokine production in situ in spleens of normal BALB/c mice monitored at the level of cytokine mRNA expression by in situ hybridization. Messenger RNAs for interleukin 2 (IL-2), interferon gamma, and tumor necrosis factors (TNF) alpha and beta were not expressed at detectable levels in spleens of unstimulated animals but became visible already 30 min after intraperitoneal application of 50 micrograms staphylococcal enterotoxin B. All mRNA levels sho…
Differential role of p38 mitogen activated protein kinase for cellular recovery from attack by pore-forming S. aureus alpha-toxin or streptolysin O.
2006
Following the observation that cells are able to recover from membrane lesions incurred by Staphylococcus aureus alpha-toxin and streptolysin O (SLO), we investigated the role of p38 in this process. p38 phosphorylation occurred in response to attack by both toxins, commencing within minutes after toxin treatment and waning after several hours. While SLO reportedly activates p38 via ASK1 and ROS, we show that this pathway does not play a major role for p38 induction in alpha-toxin-treated cells. Strikingly divergent effects of p38 blockade were noted depending on the toxin employed. In the case of alpha-toxin, inhibition of p38 within the time frame of its activation led to disruption of th…