Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
nestr.
Bakteriální rezistence stále více limituje účinnost antibiotik a rovněž velmi výrazně komplikuje schopnost léčby závažných systémových infekcí, například sepsí, což způsobuje nárůst morbidity a mortality pacientů. Slibnou možností jak překonat tento problém je kombinace klasických antibiotik s nanočásticemi stříbra. Takováto synergická kombinace umožňuje díky nespecifické aktivitě nanostříbra vysoce efektivní antibakteriální účinnost za nízkých koncentrací jak antibiotika, tak i nanočástic stříbra a současně limituje vývoj bakteriální rezistence. Cílem tohoto projektu je in vitro a in vivo aplikovaný výzkum zaměřený na možnosti použití nanočásticemi stříbra potencovaných antibiotik v léčbě systémové infekce u klinicky relevantního modelu sepse na velkém zvířeti.; Bacterial resistance increasingly limits antibiotic effectiveness, and concurrently significantly complicates antibiotic therapy of systemic infections, e.g. sepsis, resulting in higher morbidity and mortality of patients. A promising way to overcome this problem is a combination of classic antibiotics with silver nanoparticles (NPs). Thanks to non-specific activity of silver NPs, synergistic combination enables strong and effective antibacterial activity at low doses both of antibiotics and silver NPs and at the same time limits development of bacterial resistance. The aim of this project is in vitro and in vivo applied research focused on possible use of conventional antibiotics potentiated with silver NPs in therapy of systemic infection in clinically relevant large animal model of sepsis.
- Klíčová slova
- rezistence, resistance, sepse, sepsis, infekce, infection, bakterie, bacteria, Nanočástice, in vivo, in vitro, in vivo, in vitro, nanoparticle, Antibiotikum, Antibiotic, silver, antibacterial activity, synergy, stříbro, antibakteriální aktivita, synergie,
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
Silver nanoparticles have already been successfully applied in various biomedical and antimicrobial technologies and products used in everyday life. Although bacterial resistance to antibiotics has been extensively discussed in the literature, the possible development of resistance to silver nanoparticles has not been fully explored. We report that the Gram-negative bacteria Escherichia coli 013, Pseudomonas aeruginosa CCM 3955 and E. coli CCM 3954 can develop resistance to silver nanoparticles after repeated exposure. The resistance stems from the production of the adhesive flagellum protein flagellin, which triggers the aggregation of the nanoparticles. This resistance evolves without any genetic changes; only phenotypic change is needed to reduce the nanoparticles' colloidal stability and thus eliminate their antibacterial activity. The resistance mechanism cannot be overcome by additional stabilization of silver nanoparticles using surfactants or polymers. It is, however, strongly suppressed by inhibiting flagellin production with pomegranate rind extract.
- MeSH
- antibakteriální látky * chemie farmakologie MeSH
- bakteriální léková rezistence * MeSH
- Escherichia coli účinky léků MeSH
- kovové nanočástice chemie MeSH
- mikrobiální testy citlivosti MeSH
- Pseudomonas aeruginosa účinky léků MeSH
- stabilita léku MeSH
- stříbro * chemie farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Bacterial resistance to conventional antibiotics is currently one of the most important healthcare issues, and has serious negative impacts on medical practice. This study presents a potential solution to this problem, using the strong synergistic effects of antibiotics combined with silver nanoparticles (NPs). Silver NPs inhibit bacterial growth via a multilevel mode of antibacterial action at concentrations ranging from a few ppm to tens of ppm. Silver NPs strongly enhanced antibacterial activity against multiresistant, β-lactamase and carbapenemase-producing Enterobacteriaceae when combined with the following antibiotics: cefotaxime, ceftazidime, meropenem, ciprofloxacin and gentamicin. All the antibiotics, when combined with silver NPs, showed enhanced antibacterial activity at concentrations far below the minimum inhibitory concentrations (tenths to hundredths of one ppm) of individual antibiotics and silver NPs. The enhanced activity of antibiotics combined with silver NPs, especially meropenem, was weaker against non-resistant bacteria than against resistant bacteria. The double disk synergy test showed that bacteria produced no β-lactamase when treated with antibiotics combined with silver NPs. Low silver concentrations were required for effective enhancement of antibacterial activity against multiresistant bacteria. These low silver concentrations showed no cytotoxic effect towards mammalian cells, an important feature for potential medical applications.
- MeSH
- antibakteriální látky farmakologie MeSH
- beta-laktamasy genetika metabolismus MeSH
- cefotaxim farmakologie MeSH
- ceftazidim farmakologie MeSH
- ciprofloxacin farmakologie MeSH
- Escherichia coli účinky léků enzymologie genetika růst a vývoj MeSH
- exprese genu MeSH
- gentamiciny farmakologie MeSH
- Klebsiella pneumoniae účinky léků enzymologie genetika růst a vývoj MeSH
- kovové nanočástice chemie toxicita MeSH
- mikrobiální testy citlivosti MeSH
- mnohočetná bakteriální léková rezistence účinky léků genetika MeSH
- stříbro farmakologie MeSH
- synergismus léků MeSH
- thienamyciny farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The resistance of bacteria towards traditional antibiotics currently constitutes one of the most important health care issues with serious negative impacts in practice. Overcoming this issue can be achieved by using antibacterial agents with multimode antibacterial action. Silver nano-particles (AgNPs) are one of the well-known antibacterial substances showing such multimode antibacterial action. Therefore, AgNPs are suitable candidates for use in combinations with traditional antibiotics in order to improve their antibacterial action. In this work, a systematic study quantifying the synergistic effects of antibiotics with different modes of action and different chemical structures in combination with AgNPs against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus was performed. Employing the microdilution method as more suitable and reliable than the disc diffusion method, strong synergistic effects were shown for all tested antibiotics combined with AgNPs at very low concentrations of both antibiotics and AgNPs. No trends were observed for synergistic effects of antibiotics with different modes of action and different chemical structures in combination with AgNPs, indicating non-specific synergistic effects. Moreover, a very low amount of silver is needed for effective antibacterial action of the antibiotics, which represents an important finding for potential medical applications due to the negligible cytotoxic effect of AgNPs towards human cells at these concentration levels.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- bakteriální léková rezistence účinky léků MeSH
- buňky NIH 3T3 MeSH
- Escherichia coli účinky léků MeSH
- kovové nanočástice chemie MeSH
- mikrobiální testy citlivosti MeSH
- molekulární struktura MeSH
- myši MeSH
- Pseudomonas aeruginosa účinky léků MeSH
- Staphylococcus aureus účinky léků MeSH
- stříbro chemie MeSH
- synergismus léků MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nanocomposites consisting of diatomaceous earth particles and silver nanoparticles (silver NPs) with high antimicrobial activity were prepared and characterized. For the purpose of nanocomposite preparation, silver NPs with an average size of 28nm prepared by modified Tollens process were used. Nanocomposites were prepared using poly(diallyldimethylammonium) chloride (PDDA) as an interlayer substance between diatomite and silver NPs which enables to change diatomite original negative surface charge to positive one. Due to strong electrostatic interactions between negatively charged silver NPs and positively charged PDDA-modified diatomite, Ag/PDDA-diatomite nanocomposites with a high content of silver (as high as 46.6mgAg/1g of diatomite) were prepared. Because of minimal release of silver NPs from prepared nanocomposites to aqueous media (<0.3mg Ag/1g of nanocomposite), the developed nanocomposites are regarded as a potential useful antimicrobial material with a long-term efficiency showing no risk to human health or environment. All the prepared nanocomposites exhibit a high bactericidal activity against Gram-negative and Gram-positive bacteria and fungicidal activity against yeasts at very low concentrations as low as 0.11g/L, corresponding to silver concentration of 5mg/L. Hence, the prepared nanocomposites constitute a promising candidate suitable for the microbial water treatment in environmental applications.
- MeSH
- antibakteriální látky chemická syntéza chemie farmakologie MeSH
- antifungální látky chemická syntéza chemie farmakologie MeSH
- Bacteria účinky léků MeSH
- křemelina chemie farmakologie MeSH
- kvartérní amoniové sloučeniny chemie farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- nanokompozity chemie MeSH
- organokovové sloučeniny chemická syntéza chemie farmakologie MeSH
- polyethyleny chemie farmakologie MeSH
- povrchové vlastnosti MeSH
- Saccharomyces cerevisiae účinky léků MeSH
- stříbro chemie farmakologie MeSH
- velikost částic MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The use of nanoscaled materials is rapidly increasing, however, their possible ecotoxicological effects are still not precisely known. This work constitutes the first complex study focused on in vivo evaluation of the acute and chronic toxic effects and toxic limits of silver nanoparticles (NPs) on the eukaryotic organism Drosophila melanogaster. For the purpose of this study, silver NPs were prepared in the form of solid dispersion using microencapsulation method, where mannitol was used as an encapsulation agent. This newly prepared solid dispersion with a high concentration of silver NPs was exploited to prepare the standard Drosophila culture medium at a silver concentration range from 10 mg·L(-1) to 100 mg·L(-1) of Ag in the case of the acute toxicity testing and at a concentration equal to 5 mg·L(-1) in the case of the chronic toxicity testing. The acute toxic effect of silver NPs on Drosophila melanogaster was observed for the silver concentration equal to 20 mg·L(-1). At this silver concentration, 50% of the tested flies were unable to leave the pupae, and they did not finish their developmental cycle. Chronic toxicity of silver NPs was assessed by a long-term exposure of overall eight filial generations of Drosophila melanogaster to silver NPs. The long-term exposure to silver NPs influenced the fertility of Drosophila during the first three filial generations, nevertheless the fecundity of flies in subsequent generations consequently increased up to the level of the flies from the control sample due to the adaptability of flies to the silver NPs exposure.
- MeSH
- Drosophila melanogaster účinky léků MeSH
- fenotyp MeSH
- fertilita účinky léků MeSH
- kovové nanočástice toxicita MeSH
- kukla účinky léků MeSH
- larva účinky léků MeSH
- stříbro toxicita MeSH
- testy akutní toxicity MeSH
- testy chronické toxicity MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The antifungal activity of the silver nanoparticles (NPs) prepared by the modified Tollens process was evaluated for pathogenic Candida spp. by means of the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and the time-dependency of yeasts growth inhibition. Simultaneously the cytotoxicity of the silver NPs to human fibroblasts was determined. The silver NPs exhibited inhibitory effect against the tested yeasts at the concentration as low as 0.21 mg/L of Ag. The inhibitory effect of silver NPs was enhanced through their stabilization and the lowest MIC equal to 0.05 mg/L was determined for silver NPs stabilized by sodium dodecyl sulfate against Candida albicans II. The obtained MICs of the silver NPs and especially of the stabilized silver NPs were comparable and in some cases even better than MICs of the conventional antifungal agents determined by E-test. The silver NPs effectively inhibited the growth of the tested yeasts at the concentrations below their cytotoxic limit against the tested human fibroblasts determined at a concentration equal to 30 mg/L of Ag. In contrast, ionic silver inhibited the growth of the tested yeasts at the concentrations comparable to the cytotoxic level (approx. 1mg/L) of ionic silver against the tested human fibroblasts.
