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1.
Microbiol Spectr ; : e0484322, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36946744

RESUMO

Multidrug-resistant (MDR) Enterobacteriales infections have become an urgent global threat to public health. The aim of this study was to evaluate the efficacy of zidovudine-amikacin combination therapy in vitro and in vivo. Molecular characteristics and antibiotic resistance profiles of 53 amikacin-resistant MDR, extensively drug-resistant (XDR), or pan-drug-resistant (PDR) clinical isolates were examined via PCR and susceptibility testing. Checkerboard assays were performed for these 53 isolates to assess in vitro synergistic effects of the zidovudine-amikacin combination, and static time-kill experiments were performed for four XDR or PDR Enterobacteriales isolates. A Galleria mellonella model and a rat tissue cage infection model were established to assess in vivo synergistic effects. The aac(6')-Ib gene was detected in 25 (47.2%) isolates, followed by armA in 5 (9.4%) isolates, rmtB in 27 (50.9%) isolates, and rmtC in 3 (5.8%) isolates. Checkerboard assays showed the synergy of this combination against 38 (71.7%) isolates. The time-kill assays further confirmed that zidovudine strongly synergized with amikacin against four XDR or PDR Enterobacteriales isolates. The Galleria mellonella model study showed that the survival benefit of zidovudine-amikacin combination therapy was significantly better than that of monotherapy for those four Enterobacteriales isolates. Furthermore, the rat tissue cage infection model study showed that zidovudine-amikacin combination therapy displayed more potent bactericidal activity than monotherapy after 3 and 7 days of treatment for the above four isolates. Our data support the idea that the zidovudine-amikacin combination could be a plausible alternative therapy against infections with amikacin-resistant MDR Enterobacteriales, especially with XDR and PDR Enterobacteriales. IMPORTANCE Our study revealed for the first time that the zidovudine-amikacin combination shows a significant bactericidal effect against amikacin-resistant MDR, XDR, and PDR Enterobacteriales. Second, using in vitro and in vivo approaches, our study showed that zidovudine strongly synergized with amikacin against amikacin-resistant MDR Enterobacteriales isolates. Most importantly, with regard to survival benefit, pharmacokinetics, and bactericidal effects, our in vivo experiment demonstrated the effectiveness of zidovudine-amikacin.

2.
Chem Commun (Camb) ; 57(27): 3339-3342, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33657199

RESUMO

A new conjugated ionic porous organic polymer (AN-POP), incorporated with anthracene-extended viologen, has been rationally designed and prepared to explore its dual functions in photocatalytic oxidation and bacterial killing. Compared with its anthracene-free counterpart (BD-POP), AN-POP showed a superior photocatalytic oxidation performance and antibacterial activity demonstrating the critical role of an anthracene-extended viologen structure.


Assuntos
Antracenos/farmacologia , Antibacterianos/farmacologia , Polímeros/farmacologia , Viologênios/farmacologia , Antracenos/química , Antibacterianos/síntese química , Antibacterianos/química , Catálise , Escherichia coli/efeitos dos fármacos , Íons/química , Íons/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oxirredução , Tamanho da Partícula , Processos Fotoquímicos , Polímeros/química , Porosidade , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Viologênios/química
3.
Sci Rep ; 10(1): 17518, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-33060737

RESUMO

Recently, paradoxical combinations of colistin with anti-Gram-positive bacterial agents were introduced as a treatment alternative for multidrug-resistant Acinetobacter baumannii (MDRAB) infection. We assessed the therapeutic efficacy of the colistin-linezolid combination regimen in vitro and in a murine model of Acinetobacter baumannii pneumonia. A multidrug-resistant clinical strain (MDRAB31) and an extensively drug-resistant clinical strain (XDRAB78) were used in this study. The survival rates of mice and bacterial counts in lung tissue were used to assess the effects of colistin-linezolid combination. The survival rates of colistin-linezolid combination groups significantly increased compared with colistin groups for MDRAB31 (72% versus 32%, P = 0.03) and for XDRAB78 (92% versus 68%, P = 0.031). The colistin-linezolid combination groups significantly reduced the bacterial counts in lung tissue compared with colistin groups for MDRAB31 and for XDRAB78 (P < 0.05). The colistin-linezolid combination had a bactericidal and synergistic effect compared with colistin alone in time-kill assay and in murine model of pneumonia. Our data demonstrated the synergistic effect of colistin-linezolid combination regimen as a treatment alternative for the severe pulmonary infection caused by MDRAB and XDRAB.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Antituberculosos/uso terapêutico , Colistina/administração & dosagem , Tuberculose Extensivamente Resistente a Medicamentos/tratamento farmacológico , Linezolida/administração & dosagem , Pneumonia Bacteriana/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Acinetobacter baumannii/metabolismo , Animais , Modelos Animais de Doenças , Sinergismo Farmacológico , Tuberculose Extensivamente Resistente a Medicamentos/microbiologia , Feminino , Pulmão/efeitos dos fármacos , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Pneumonia Bacteriana/microbiologia , Fatores de Tempo , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
4.
Soft Matter ; 13(22): 4074-4079, 2017 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-28537314

RESUMO

A novel C3-symmetric benzene-1,3,5-tricarboxamide (BTAs) decorated with three identical pillar[5]arene tails was designed, synthesized and characterized. The compound can gelate acetonitrile at low concentration (0.2 wt%) upon sonication at room temperature, but a precipitate was obtained by a conventional heating-cooling process. Scanning electron microscopy revealed that the gel and precipitate were constructed by entangled, high-aspect-ratio flexible bundles of nanofibrils. UV-vis spectroscopy, circular dichroism, Fourier transform infrared microscopy and powder X-ray diffraction showed that the compound formed chiral, elongated, columnar aggregates with nanofiber morphology by a combination of intermolecular hydrogen bonding between the N-H and C[double bond, length as m-dash]O of amides, π-π stacking (H-aggregates) and hydrophobic interactions of peripheral groups.

5.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(6): 1597-600, 2015 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-26601374

RESUMO

Anions are ubiquitously distributed not only in biological systems but also in environment. Accordingly, anion recognition and sensing have attracted increasing attention due to the important roles anion plays in biological, chemical and environmental fields. Among various anionic species, NO3- is a very important inorganic anions which has a great harm to the environment and human health. At present, methods for the determination of NO3- mainly contained electrochemical method, ion chromatography and ion selective electrode method. Although all methods have their own advantages, but also has the obvious deficiency. Such as, the reproducibility of electrochemical method is not good, and ion chromatography and ion selective electrode method usually require expensive apparatus and lengthy analytical time. As a contrast, fluorescence spectroscopy become a hot research topic in anion recognition and detection because of its high sensitivity and easy operation and other advantages in recent years. New bipyridinium salt L was designed and synthesized using pyrylium as a starting material. The molecular structure was determined by 1H NMR, 13C NMR, and high resolution mass spectrometry. The molecular recognition properties of L have been investigated through fluorescence titration experiments. The results indicate that L has sensitive and selective fluorescent response to NO3- among other different anions. Significant enhancements in the fluorescence intensity of L were observed when various concentrations of NO3- were added, while other competing anions have a quenching effect towards the initial fluorescence of solution. The fluorescence titration spectra shows that the bonding stoichiometry between receptor L and NO3- is 1 : 1 as a supramolecular complexes (1gK = 5 ± 0.02). The chemosensing properties of L were evaluated through quantum chemical calculations and the variable temperature 1H NMR titration. These results suggested that L has strong binding affinity towards NO3- with high selectivity, which may be ascribed to the specific hydrogen bonding between the L and active H atom of the bipyrydinium salts. The interaction between L and NO3- made the complex more planar compared with L giving rise to enhanced fluorescence and specific selectivity towards NO3-.


Assuntos
Ânions/química , Corantes Fluorescentes/química , Nitratos/química , Compostos de Piridínio/química , Ligação de Hidrogênio , Estrutura Molecular , Reprodutibilidade dos Testes , Espectrometria de Fluorescência
6.
Org Biomol Chem ; 13(7): 1979-82, 2015 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-25563510

RESUMO

Gemini surfactant-like receptor is designed and synthesized. The special preassembly phenomenon of in a nonpolar solvent facilitates the novel ratiometric fluorescence sensing of H2PO4(-)via an anion-induced reassembly process in organic solvents and an anion-induced disassembly process in water.

7.
Antimicrob Agents Chemother ; 58(11): 6773-81, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25182633

RESUMO

The emergence of resistance to carbapenems in Pseudomonas aeruginosa can be suppressed by optimizing the administration of meropenem. However, whether the same is true for Acinetobacter baumannii is not fully understood. We assessed the bactericidal activity of meropenem and its potency to suppress the emergence of resistance in A. baumannii with human simulated exposure in an in vitro intravenous-infusion hollow-fiber infection model (HFIM). Two clinical strains of carbapenem-susceptible multidrug-resistant A. baumannii (CS-MDRAB), CSRA24 and CSRA91, were used, and their MICs and mutant prevention concentrations (MPCs) were determined. Six meropenem dosage regimens (0.5, 1.0, or 2.0 g given every 8 h [q8h] with a 0.5-h or 3-h infusion for seven consecutive days) were simulated and then evaluated in the HFIM. Both the total population and resistant subpopulations of the two strains were quantified. Drug concentrations were measured by high-performance liquid chromatography. All dosage regimens, except for the lowest dosage (0.5 g for both the 0.5-h and 3-h infusions), showed 3-log CFU/ml bacterial killing. Dosage regimens of 2.0 g with 0.5-h and 3-h infusions exhibited an obvious bactericidal effect and suppressed resistance. Selective amplification of subpopulations with reduced susceptibility to meropenem was suppressed with a percentage of the dosage interval in which meropenem concentrations exceeded the MPC (T>MPC) of ≥20% or with a ratio of T>MPC to the percentage of the dosage interval in which drug concentrations are within the mutant selection window of ≥0.25. Our in vitro data support the use of a high dosage of meropenem (2.0 g q8h) for the treatment of severe infection caused by CS-MDRAB.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Tienamicinas/farmacologia , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla , Humanos , Meropeném , Testes de Sensibilidade Microbiana
8.
ACS Appl Mater Interfaces ; 5(23): 12411-8, 2013 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-24224803

RESUMO

The porous hierarchical MgO with superb adsorption properties has been synthesized by a facile and scaled-up method. The X-ray powder diffraction, electron microscopy, Fourier transformed infrared, and N2 adsorption-desorption were carried out to study the microstructure of the as-synthesized precursor and product. It has been demonstrated that the as-prepared MgO has a porous hierarchical structure and a high specific surface area (148 m(2) g(-1)). And the MgO sample exhibited super adsorption properties, with maximum adsorption capacity of 2409 mg g(-1) for Congo red, which is the highest reported value. Moreover, the adsorption process of Congo red on porous hierarchical MgO was systematically investigated, which was found to obey the pseudo-second-order rate equation and Langmuir adsorption model.

9.
Dalton Trans ; 42(28): 10093-6, 2013 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-23728488

RESUMO

Efficient ratiometric fluorescent Fe(3+) probes were designed and synthesized by linking a conjugated naphthalene chromophore to a rhodamine platform and a lipophilic triphenylphosphonium (TPP) cation. The probes could sensitively and selectively detect mitochondrial Fe(3+) in living cells.


Assuntos
Corantes Fluorescentes/química , Ferro/análise , Mitocôndrias/química , Transferência Ressonante de Energia de Fluorescência , Células HeLa , Humanos , Ferro/química , Naftalenos/química , Compostos Organofosforados/química , Rodaminas/química
10.
Artigo em Inglês | MEDLINE | ID: mdl-23602425

RESUMO

A new conjugated phosphonium salt TPP was synthesized readily from phosphine-triggered ring-opening of 2,4,5-triphenylpyrylium salt. In aqueous solution, it exhibited interesting AIEE properties and self-assembled into fluorescent nanoparticles, which can be used as a fluorescence probe to image mitochondria in cells.


Assuntos
Corantes Fluorescentes/análise , Mitocôndrias/ultraestrutura , Nanopartículas/análise , Fosfinas/análise , Células HEK293 , Humanos , Microscopia Confocal , Nanopartículas/ultraestrutura , Sais/análise
11.
J Org Chem ; 70(14): 5768-70, 2005 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-15989371

RESUMO

[reaction: see text] Oxidation of substituted cyclopentadienes by molecular oxygen afforded the corresponding pyrylium cations in acidic solution, whereby an oxygen atom was inserted into the cyclopentadiene ring. This novel one-step reaction proceeds in a different yield depending on substitution patterns of the cyclopentadiene. A possible reaction pathway and formation mechanism of the pyrylium cation are proposed and discussed.

12.
Spectrochim Acta A Mol Biomol Spectrosc ; 62(4-5): 835-9, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15950527

RESUMO

Two novel phenylated pyrylium compounds, silver (I)-bridged 2,3,4,5-tetraphenylpyrylium perchlorate (P1) and its silver (I)-free pyrylium ligand (P2) were prepared from 1,2,3,4-tetraphenylcyclopentadiene to examine their spectroscopic behaviors. The UV/vis absorption and fluorescent emission spectra of P1 and P2, measured in three solvents (acetonitrile, dichloromethane and toluene), reveal that the photophysical behaviors are closely related to silver (I) fragment, and strongly dependent on solvent polarity. In polar acetonitrile, P1 displays longer absorption wavelength and much lower fluorescent emission intensity than P2, although they exhibit much similarity in shape. In contrast, in nonpolar toluene, while P2 shows an apparent absorption band at 338 nm, P1 displays a tail-like line without absorption band observed. All the spectra obtained indicate a better coplanarity and a stronger intra-molecular charge transfer in P1 due to the effect of silver (I) fragment. Additionally, the 1H NMR spectra of P1 and P2, which were recorded under the same conditions, indicate that the silver (I) fragment reinforces pyrylium ring's capacity to localize the formal positive charge within the heterocyclic ring.


Assuntos
Compostos Heterocíclicos com 3 Anéis/química , Sais/química , Prata/química , Espectroscopia de Ressonância Magnética , Solventes , Espectrometria de Fluorescência
13.
J Org Chem ; 69(4): 1432-4, 2004 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-14961713

RESUMO

Phenyl-substituted cyclopentadienes are proved to form phenylated pyrylium cations in the presence of silver(I) perchlorate by insertion of an oxygen atom into the cyclopentadiene-ring. Three phenylated pyrylium compounds, [(Ph(5)C(5)O(+))(ClO(4)(-))](2)(CH(2)Cl(2)) (1), Ag(ClO(4))(H(2)O)(Ph(4)HC(5)O(+)) (ClO(4)(-)) (2), and (Ph(3)H(2)C(5)O(+))(ClO(4)(-)) (3) have been synthesized and characterized. A possible reaction pathway and formation mechanism of the pyrylium cation are proposed and discussed.

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