Gram-negative bacteria Dotaz Zobrazit nápovědu
Elastase of Vibrio cholerae caused the lysis of freshly grown cells of Gram-negative (Pseudomonas aeruginosa, Proteus vulgaris, Salmonella paratyphi A and Klebsiella pneumoniae) bacteria. Gram-positive (Staphylococcus aureus and S. epidermidis) organisms were resistant to this enzyme. Heat killed and lyophilized Gram-positive and -negative bacteria (except S. aureus and S. epidermidis) showed higher sensitivity to elastase. Both Gram-negative and -positive bacteria were lyzed maximally by elastase at pH 8.0. At this pH, lytic activity of elastase was maximum in Tris-HCl and glycine-NaOH buffers followed by Tris-maleate and cacodylate buffers.
- MeSH
- bakteriolýza * MeSH
- gramnegativní bakterie metabolismus MeSH
- grampozitivní bakterie metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- pankreatická elastasa metabolismus MeSH
- Vibrio cholerae enzymologie MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- pankreatická elastasa MeSH
Outer membrane vesicles secreted by gram-negative bacteria play an important role in bacterial physiology as well as in virulence and host-pathogen interaction. Isolated vesicles of some bacteria have also been studied for their immunomodulatory potential in the vaccine development. However, the production of vesicles in sufficient amount, purity and reproducibility remains a critical challenge for subsequent analyses in most bacteria. In the present review methods of production, isolation, purification and quantification of outer membrane vesicles are summarized and discussed.
- Klíčová slova
- Bacterial secretion, Gram-negative bacteria, Host–pathogen interaction, Outer membrane vesicles, Vaccine development,
- MeSH
- buněčná stěna * imunologie metabolismus MeSH
- frakcionace buněk metody MeSH
- fyziologický stres MeSH
- genetické inženýrství MeSH
- gramnegativní bakterie * genetika imunologie metabolismus MeSH
- sekreční vezikuly * imunologie metabolismus MeSH
- subcelulární frakce MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Innate immune surveillance in the blood is executed mostly by circulating monocytes, which recognize conserved bacterial molecules such as peptidoglycan and lipopolysaccharide. Toll-like receptors (TLR) play a central role in microbe-associated molecular pattern detection. The aim of this study was to compare the differences in TLR expression and cytokine production after stimulation of peripheral blood cells with heat-killed gram-negative and gram-positive human pathogens: Neisseria meningitidis, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. We found that TLR2 expression is up-regulated on monocytes after stimulation with S. aureus, S. pneumoniae, E. coli, and N. meningitidis. Moreover, TLR2 up-regulation was positively associated with increasing concentrations of gram-positive bacteria, whereas higher concentrations of gram-negative bacteria, especially E. coli, caused a milder TLR2 expression increase when compared to low doses. Cytokines were produced in similar dose-dependent profiles regardless of the stimulatory pathogen; however, gram-negative pathogens induced higher cytokine levels when compared to gram-positive bacteria at the same density. These results indicate that gram-positive and gram-negative bacteria differ in their dose-dependent patterns of induction of TLR2 and TLR4, but not cytokine expression.
- MeSH
- cytokiny metabolismus MeSH
- gramnegativní bakterie imunologie MeSH
- grampozitivní bakterie imunologie MeSH
- kultivované buňky MeSH
- leukocyty mononukleární imunologie MeSH
- lidé MeSH
- toll-like receptor 2 biosyntéza MeSH
- toll-like receptor 4 biosyntéza MeSH
- vysoká teplota * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokiny MeSH
- TLR2 protein, human MeSH Prohlížeč
- TLR4 protein, human MeSH Prohlížeč
- toll-like receptor 2 MeSH
- toll-like receptor 4 MeSH
- Klíčová slova
- Gram, Gram-negative, Gram-positive, SensiGram,
- MeSH
- bakteriální nálož MeSH
- barvení a značení metody MeSH
- Escherichia coli MeSH
- fenaziny * MeSH
- genciánová violeť * MeSH
- gramnegativní bakteriální infekce diagnóza MeSH
- gramnegativní bakterie izolace a purifikace MeSH
- krev mikrobiologie MeSH
- kultivační vyšetření krve MeSH
- senzitivita a specificita MeSH
- Staphylococcus aureus MeSH
- techniky typizace bakterií metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- fenaziny * MeSH
- genciánová violeť * MeSH
- Gram's stain MeSH Prohlížeč
OBJECTIVES: The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) is a global surveillance programme monitoring the in vitro activity of a panel of antimicrobial agents against clinically important bacterial isolates. Data for Gram-positive and Gram-negative isolates collected in Eastern Europe between 2011 and 2016 are presented here. METHODS: Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method using CLSI guidelines. Antimicrobial susceptibility was assessed using EUCAST breakpoints. RESULTS: Nine Eastern European countries submitted 4289 isolates. Among Acinetobacter baumannii, resistance to levofloxacin, amikacin and meropenem was 77.5%, 63.4% and 62.2%, respectively. Multidrug resistance among A. baumannii was higher in 2015 than in previous years (44.1% in 2011 and 71.0% in 2015), decreasing to 51.7% in 2016. The multidrug resistance percentage for Pseudomonas aeruginosa was 26.9% and was relatively stable over time. The percentage of extended-spectrum β-lactamase (ESBL)-positive isolates among Escherichia coli and Klebsiella pneumoniae was 20.1% and 55.7%, respectively. Resistance to amikacin, meropenem and tigecycline was low among E. coli and K. pneumoniae and the ESBL-producing subset (≤5.9%). Among Staphylococcus aureus isolates, 36.7% were methicillin-resistant (MRSA); percentages varied year-on-year. No S. aureus isolates, including MRSA, were resistant to linezolid, vancomycin or tigecycline. Among Enterococcus faecium isolates, resistance was 22.6% to vancomycin and 2.3% to linezolid; no isolates were resistant to tigecycline. CONCLUSION: This study shows low resistance to meropenem and tigecycline among Enterobacteriaceae isolates and continued activity of linezolid, vancomycin and tigecycline against Gram-positive organisms. However, antimicrobial resistance continues to be problematic in Eastern Europe and requires continued surveillance.
- Klíčová slova
- Eastern Europe, Gram-negative, Gram-positive, Resistance, Surveillance, Tigecycline,
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence MeSH
- dospělí MeSH
- gramnegativní bakteriální infekce mikrobiologie MeSH
- gramnegativní bakterie klasifikace účinky léků genetika izolace a purifikace MeSH
- grampozitivní bakteriální infekce mikrobiologie MeSH
- grampozitivní bakterie klasifikace účinky léků genetika izolace a purifikace MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mladiství MeSH
- mladý dospělý MeSH
- senioři MeSH
- tigecyklin farmakologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- východní Evropa MeSH
- Názvy látek
- antibakteriální látky MeSH
- tigecyklin MeSH
The on time diagnostics of bacterial diseases is one of the essential steps in the foregoing treatment of such pathogens. Here we sought to present an easy to use and robust method for the discrimination between Gram-positive (Enterococcus faecalis and Streptococcus pyogenes) and Gram-negative (Acinetobacter baumannii and Klebsiella pneumoniae) bacterial genera based on surface enhanced Raman scattering (SERS) spectroscopy. The robustness of our approach lies in the novel method for the production of the SER substrate based on silver nanoparticles and their subsequent re-crystallization in solutions containing high concentrations of chloride ions. The method presented here could be an interesting alternative both to commonly used histochemical approaches and commercial SERS substrates.
- MeSH
- buněčná smrt MeSH
- časové faktory MeSH
- gramnegativní bakterie chemie cytologie izolace a purifikace MeSH
- grampozitivní bakterie chemie cytologie izolace a purifikace MeSH
- povrchové vlastnosti MeSH
- Ramanova spektroskopie * MeSH
- reprodukovatelnost výsledků MeSH
- shluková analýza MeSH
- spektrofotometrie infračervená MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Coelomic fluid of Eisenia foetida earthworms (Oligochaeta, Annelida) contains a 42-kDa defense molecule named CCF for coelomic cytolytic factor. By binding microbial antigens, namely the O-antigen of lipopolysaccharide (LPS), beta-1,3-glucans, or N,N'-diacetylchitobiose present, respectively, on Gram-negative bacteria or yeast cell walls, CCF triggers the prophenoloxidase activating pathway. We report that CCF recognizes lysozyme-predigested Gram-positive bacteria or the peptidoglycan constituent muramyl dipeptide as well as muramic acid. To identify the pattern recognition domains of CCF, deletion mutants were tested for their ability to reconstitute the prophenoloxidase cascade in E. foetida coelomic fluid depleted of endogenous CCF in the presence of LPS, beta-1,3-glucans, N,N'-diacetylchitobiose, and muramic acid. In addition, affinity chromatography of CCF peptides was performed on immobilized beta-1,3-glucans or N,N'-diacetylchitobiose. We found that the broad specificity of CCF for pathogen-associated molecular patterns results from the presence of two distinct pattern recognition domains. One domain, which shows homology with the polysaccharide and glucanase motifs of beta-1,3-glucanases and invertebrate defense molecules located in the central part of the CCF polypeptide chain, interacts with LPS and beta-1,3-glucans. The C-terminal tryptophan-rich domain mediates interactions of CCF with N,N'-diacetylchitobiose and muramic acid. These data provide evidence for the presence of spatially distinct carbohydrate recognition domains within this invertebrate defense molecule.
- MeSH
- aktivace enzymů MeSH
- cytotoxiny chemie metabolismus MeSH
- DNA primery MeSH
- gramnegativní bakterie metabolismus MeSH
- grampozitivní bakterie metabolismus MeSH
- lektiny * MeSH
- metabolismus sacharidů * MeSH
- molekulární sekvence - údaje MeSH
- Oligochaeta enzymologie metabolismus MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- tyrosinasa metabolismus MeSH
- vazebná místa MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- coelomic cytolytic factor 1, Eisenia fetida MeSH Prohlížeč
- cytotoxiny MeSH
- DNA primery MeSH
- lektiny * MeSH
- tyrosinasa MeSH
Innate immune surveillance in the blood is executed mostly by circulating monocytes, which recognise conserved bacterial molecules such as peptidoglycan and lipopolysaccharide. Toll-like receptors (TLR) play a central role in microbe-associated molecular pattern detection. Here, we compared the differences in TLR expression and cytokine production after stimulation of peripheral blood cells with heat-killed Gram-negative and Gram-positive human pathogens Neisseria meningitidis, Escherichia coli, Staphylococcus aureus and Streptococcus pneumoniae. We found that TLR2 expression is up-regulated on monocytes after stimulation with S. aureus, S. pneumoniae, E. coli and N. meningitidis. Moreover, TLR2 up-regulation was positively associated with increasing concentrations of Gram-positive bacteria, whereas higher concentrations of Gram-negative bacteria, especially E. coli, caused a milder TLR2 expression increase compared with low doses. Cytokines were produced in similar dose-dependent profiles regardless of the stimulatory pathogen; however, Gram-negative pathogens induced higher cytokine levels than Gram-positive ones at same concentrations. These results indicate that Gram-positive and Gram-negative bacteria differ in their dose-dependent patterns of induction of TLR2 and TLR4, but not in cytokine expression.
- MeSH
- aktivace transkripce MeSH
- cytokiny biosyntéza MeSH
- gramnegativní bakterie genetika imunologie MeSH
- grampozitivní bakterie genetika imunologie MeSH
- lidé MeSH
- monocyty imunologie MeSH
- přirozená imunita MeSH
- regulace genové exprese MeSH
- signální transdukce imunologie MeSH
- toll-like receptor 2 biosyntéza genetika imunologie MeSH
- toll-like receptor 4 biosyntéza genetika imunologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokiny MeSH
- toll-like receptor 2 MeSH
- toll-like receptor 4 MeSH
Quorum-sensing control mediated by N-acylhomoserine lactone (AHL) signal molecules has been established as a key feature in the regulation of various metabolic traits in many bacteria. Approximately 300 strains representing 6 genera and 18 species of soil-borne and plant-associated Gram-negative bacteria isolated in various regions of the former USSR using two reporter systems were screened for AHL production. The production was observed in 17.5% of the screened bacterial strains. Positive response was detected in all of the 14 tested strains of Erwinia herbicola, in 41 of the 239 strains of Pseudomonas species; in all 5 strains of Xanthomonas ampelina, X. campestris pv. malvacearum, pv. translucens, pv. vesicatoria and in one strain of Pantoea stewartii. AHL assay of 41 strains of X. maltophilia (syn. Stenotrophomonas maltophilia) isolated from soils with Chromobacterium violaceum reporter has revealed no strains synthesizing these signal molecules; 26 strains analyzed with Agrobacterium tumefaciens reporter showed the same result.
- MeSH
- gama-butyrolakton analogy a deriváty biosyntéza metabolismus MeSH
- gramnegativní bakterie růst a vývoj metabolismus MeSH
- půdní mikrobiologie * MeSH
- rostliny mikrobiologie MeSH
- signální transdukce fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- gama-butyrolakton MeSH
- homoserine lactone MeSH Prohlížeč