RESUMEN
BACKGROUND: Bacterial resistance is defined as a microorganism's capacity to develop mechanisms for resisting a determined antimicrobial. Gram-positive bacteria, such as Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis), are internationally recognized among the isolates with this resistance profile. In this context, the demand for new medicines has risen, and silver nanoparticles (AgNPs) have been highlighted, especially for their anti-bacterial effects. To develop a nano-antibiotic for treating these Gram-positive strains, we herein report synthesizing and characterizing a nano-antibiotic based on AgNPs functionalized with the complex vancomycin-cysteamine. METHODS: AgNPs were produced using the bottom-up methodology and functionalized with vancomycin modified by the carbodiimide chemistry, forming Ag@vancomycin. Susceptibility tests were performed using S. aureus and E. faecalis strains to assess the bacteriostatic and bactericidal potential of the developed nano-antibiotic. RESULTS: Fourier transform infrared spectroscopy measurements showed the efficacy of vancomycin chemical modification, and the characteristic bands of AgNPs functionalization with the antibiotic. The increase in the nano-antibiotic average hydrodynamic diameter observed by dynamic light scattering proved the presence of vancomycin at the surface of AgNPs. The data from the minimum inhibitory concentration and minimal bactericidal concentration assays tested on standard and clinical planktonic strains of S. aureus and E. faecalis presented excellent performance. CONCLUSION: The results indicate the promising development of a new nano-antibiotic in which the functionalization potentiates the bacteriostatic action of AgNPs and vancomycin with greater efficacy against Gram-positive strains.
Asunto(s)
Antibacterianos , Nanopartículas del Metal , Antibacterianos/farmacología , Vancomicina/farmacología , Vancomicina/química , Staphylococcus aureus , Enterococcus faecalis , Plata/farmacología , Cisteamina/farmacología , Nanopartículas del Metal/química , Pruebas de Sensibilidad MicrobianaRESUMEN
OBJECTIVE: to verify the stability of vancomycin hydrochloride in antimicrobial seal solutions with and without association of heparin sodium according to temperature and association time. METHOD: an experimental study designed for the analysis of hydrogenionic potential and concentration by means of high-efficiency liquid chromatography of vancomycin hydrochloride (n=06) and vancomycin hydrochloride and heparin sodium (n=06). The solutions studied were submitted to absence of light, as well as to 22°C and 37°C. Analyses in triplicate (n=192) were performed at the initial moment (T0) and three (T3), eight (T8) and 24 hours (T24) after preparation. The data were submitted to analysis of variance (p≤0.05). RESULTS: concentration of the antimicrobial at 22°C presented a reduction (T0-T8) and a subsequent increase (T24); hydrogenionic potential decreased significantly over time. At 37°C, the concentration increased up to T3 and decreased at T24, with a reduction of hydrogenionic potential up to 24 hours. Concentration of the vancomycin hydrochloride and heparin sodium solutions varied with a reduction at 22°C, accompanied by increased hydrogenionic potential. Precipitate formation was observed by visual inspection of the vancomycin hydrochloride-heparin sodium association (T3). CONCLUSION: pharmacological stability of vancomycin hydrochloride (5 mg/mL) and physical incompatibility with heparin sodium (100 IU/mL) were evidenced after three hours of association in the antimicrobial seal solutions studied.
Asunto(s)
Catéteres Venosos Centrales , Vancomicina , Antibacterianos , Estabilidad de Medicamentos , Heparina , Humanos , Vancomicina/químicaRESUMEN
The rotary jet spinning technique permits the production of biomaterials that can be used as devices that come into contact with biological systems (including biological fluids) for diagnostic or surgical applications. These materials are composed of synthetic or natural compounds and allow the incorporation of drugs for therapeutic purposes. Two solutions containing 50% poly(lactic acid) (PLA) and 50% poly(ε-caprolactone) (PCL) diluted in three different solvents were prepared for rotary jet spinning (RJS) process. Vancomycin, an antibiotic indicated for the treatment of severe staphylococcal infections in patients with penicillin allergy, was added in the polymer solutions, to obtain drug-loaded fibrous mats. Morphological surface characterization by scanning electron microscopy revealed heterogeneous pores in the microfibers. Vancomycin loading interfered with the morphology of all samples in terms of fiber size, leading to smaller diameter fibers. Attenuated total reflectance/Fourier transform infrared spectroscopy was used for identification of the samples. The vibrational characteristics of PCL/PLA and vancomycin were consistent with expectations. Vero cell culture assays by the extract dilution and direct contact methods revealed the absence of cytotoxicity, except for the sample prepared with 50% of PCL and of a 9/2 (V/V) vancomycin content, with the growth of confluent and evenly spread cells on the fibrous mats surface. Microbiological analysis, performed on Staphylococcus aureus by the halo inhibition test and by the broth dilution method, showed that the antibacterial activity of vancomycin was maintained by the loading process in the polymer fibers. The results showed that rotary jet spinning produces satisfactory amounts of Vancomycin-loaded fibers, as potential web dressing for wound repair.
Asunto(s)
Antiinfecciosos , Nanofibras , Vendajes , Humanos , Ácido Láctico , Nanofibras/química , Poliésteres/química , Polímeros/química , Andamios del Tejido/química , Vancomicina/químicaRESUMEN
Resumo Objetivo: verificar a estabilidade do cloridrato de vancomicina em soluções de selo antimicrobiano sem e com associação de heparina sódica segundo a temperatura e tempo de associação. Método: estudo experimental delineado para análise de potencial hidrogeniônico e concentração por cromatografia líquida de alta eficiência de soluções de cloridrato de vancomicina (n=06) e cloridrato de vancomicina e heparina sódica (n=06). Submeteram-se as soluções estudadas à ausência de luz, 22°C e 37°C. Análises em triplicadas (n=192) ocorreram no momento inicial (T0), três (T3), oito (T8) e 24 horas (T24) após preparo. Os dados foram submetidos à análise de variância (p≤0,05). Resultados: a concentração do antimicrobiano a 22°C apresentou redução (T0-T8) e posterior elevação (T24); o potencial hidrogeniônico diminuiu significativamente ao longo do tempo. Em 37°C a concentração aumentou em até T3 e reduziu em T24, com redução de potencial hidrogeniônico até 24 horas. A concentração das soluções de cloridrato de vancomicina e heparina sódica apresentaram variação com redução a 22°C acompanhada de aumento de potencial hidrogeniônico. Observou-se formação de precipitado por inspeção visual da associação cloridrato de vancomicina e heparina sódica (T3). Conclusão: evidenciou-se estabilidade farmacológica do cloridrato de vancomicina (5 mg/mL) e incompatibilidade física com heparina sódica (100 UI/mL) após três horas de associação nas soluções de selo antimicrobiano estudadas.
Abstract Objective: to verify the stability of vancomycin hydrochloride in antimicrobial seal solutions with and without association of heparin sodium according to temperature and association time. Method: an experimental study designed for the analysis of hydrogenionic potential and concentration by means of high-efficiency liquid chromatography of vancomycin hydrochloride (n=06) and vancomycin hydrochloride and heparin sodium (n=06). The solutions studied were submitted to absence of light, as well as to 22°C and 37°C. Analyses in triplicate (n=192) were performed at the initial moment (T0) and three (T3), eight (T8) and 24 hours (T24) after preparation. The data were submitted to analysis of variance (p≤0.05). Results: concentration of the antimicrobial at 22°C presented a reduction (T0-T8) and a subsequent increase (T24); hydrogenionic potential decreased significantly over time. At 37°C, the concentration increased up to T3 and decreased at T24, with a reduction of hydrogenionic potential up to 24 hours. Concentration of the vancomycin hydrochloride and heparin sodium solutions varied with a reduction at 22°C, accompanied by increased hydrogenionic potential. Precipitate formation was observed by visual inspection of the vancomycin hydrochloride-heparin sodium association (T3). Conclusion: pharmacological stability of vancomycin hydrochloride (5 mg/mL) and physical incompatibility with heparin sodium (100 IU/mL) were evidenced after three hours of association in the antimicrobial seal solutions studied.
Resumen Objetivo: verificar la estabilidad del clorhidrato de vancomicina en soluciones de sellado antimicrobiano solo y combinado con heparina sódica según la temperatura y el tiempo de combinación. Método: estudio experimental diseñado para analizar el potencial de hidrógeno y la concentración por cromatografía líquida de alta resolución de soluciones de clorhidrato de vancomicina (n=06) y de clorhidrato de vancomicina y heparina sódica (n=06). Las soluciones estudiadas fueron sometidas a ausencia de luz, 22°C y 37°C. Se realizaron análisis por triplicado (n=192) en el momento inicial (T0), a las tres (T3), ocho (T8) y 24 horas (T24) después de la preparación. Los datos fueron sometidos a análisis de varianza (p≤0,05). Resultados: la concentración de antimicrobiano a 22°C mostró una reducción (T0-T8) y un posterior aumento (T24); el potencial de hidrógeno disminuyó significativamente con el tiempo. A 37°C, la concentración aumentó hasta T3 y disminuyó en T24, el potencial de hidrógeno disminuyó hasta las 24 horas. La concentración de las soluciones de clorhidrato de vancomicina y heparina sódica mostró variación con la reducción a 22°C acompañada de un aumento del potencial de hidrógeno. Mediante inspección visual se observó la formación de un precipitado al combinar clorhidrato de vancomicina y heparina sódica (T3). Conclusión: el clorhidrato de vancomicina (5 mg/ml) presentó evidencia de estabilidad farmacológica e incompatibilidad física con la heparina sódica (100 UI/ml) después de las tres horas de haberse realizado la combinación en las soluciones de sellado antimicrobiano estudiadas.
Asunto(s)
Heparina , Vancomicina/química , Estabilidad de Medicamentos , Infecciones Relacionadas con Catéteres , Catéteres Venosos CentralesRESUMEN
Vancomycin-loaded N,N-dodecyl,methyl-polyethylenimine nanoparticles coated with hyaluronic acid (VCM-DMPEI nanoparticles/HA) were synthesized as an adjuvant for the treatment of bacterial endophthalmitis. The nanoparticles were formulated by experimental statistical design, thoroughly characterized, and evaluated in terms of bactericidal activity and both in vitro and in vivo ocular biocompatibility. The VCM-DMPEI nanoparticles/HA were 154 ± 3 nm in diameter with a 0.197 ± 0.020 polydispersity index; had a + 26.4 ± 3.3 mV zeta potential; exhibited a 93% VCM encapsulation efficiency; and released 58% of the encapsulated VCM over 96 h. VCM and DMPEI exhibited a synergistic bactericidal effect. The VCM-DMPEI nanoparticles/HA were neither toxic to ARPE-19 cells nor irritating to the chorioallantoic membrane. Moreover, the VCM-DMPEI nanoparticles/HA did not induce modifications in retinal functions, as determined by electroretinography, and in the morphology of the ocular tissues. In conclusion, the VCM-DMPEI nanoparticles/HA may be a useful therapeutic adjuvant to treat bacterial endophthalmitis.
Asunto(s)
Endoftalmitis/tratamiento farmacológico , Polietileneimina/análogos & derivados , Vancomicina/farmacología , Antibacterianos/farmacología , Línea Celular , Portadores de Fármacos , Liberación de Fármacos , Ojo/efectos de los fármacos , Humanos , Ácido Hialurónico/metabolismo , Ácido Hialurónico/farmacología , Nanopartículas , Tamaño de la Partícula , Polietileneimina/química , Polietileneimina/farmacología , Vancomicina/químicaRESUMEN
Bacterial infections represent one of the leading causes of mortality in the world. Among causative pathogens, S. aureus is prominently known as the underlying cause of many multidrug resistant infections that are often treated with the first-line choice antibiotic vancomycin (VCM). Loading antibiotics into polymeric nanoparticles (Np) displays promise as an alternative method to deliver therapy due to the greater access and accumulation of the antibiotic at the site of the infection as well as reducing toxicity, irritation and degradation. The aim of this work was to prepare, characterize and evaluate VCM-loaded nanoparticles (VNp) for use against S. aureus strains. Moreover, conjugation of Nps with holo-transferrin (h-Tf) was investigated as an approach for improving targeted drug delivery. VNp were prepared by double emulsion solvent evaporation method using PLGA and PVA or DMAB as surfactants. The particles were characterized for size distribution, Zeta Potential, morphology by transmission electron microscopy, encapsulation yield and protein conjugation efficiency. Process yield and drug loading were also investigated along with an in vitro evaluation of VNp antimicrobial effects against S. aureus strains. Results showed that Np were spontaneously formed with a mean diameter lower than 300 nm in a narrow size distribution that presented a spherical shape. The bioconjugation with h-Tf did not appear to increase the antimicrobial effect of VNp. However, non-bioconjugated Np presented a minimal inhibitory concentration lower than free VCM against a MRSA (Methicillin-resistant S. aureus) strain, and slightly higher against a VISA (VCM intermediate S. aureus) strain. VNp without h-Tf showed potential to assist in the development of new therapies against S. aureus infections.
Asunto(s)
Antibacterianos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Nanopartículas/química , Vancomicina/farmacología , Antibacterianos/química , Portadores de Fármacos/química , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Staphylococcus aureus/efectos de los fármacos , Transferrina/química , Vancomicina/químicaRESUMEN
Compounded liquid medication is frequently required in children to allow easy dose adjustment and overcome swallowing difficulties. The objective of this study was to evaluate the stability of oral suspensions compounded with SyrSpend SF PH4 and the commonly used active pharmaceutical ingredients baclofen 2.0 mg/mL, carvedilol 5.0 mg/mL, hydrochlorothiazide 2.0 mg/mL, mercaptopurine 10.0 mg/mL, methadone hydrochloride 10.0 mg/mL, oseltamivir phosphate 6.0 mg/mL, phenobarbital 9.0 mg/mL and 15.0 mg/mL, propranolol hydrochloride 0.5 mg/mL and 5.0 mg/mL, pyrazinamide 100.0 mg/mL, spironolactone 2.0 mg/mL and 2.5 mg/mL, sotalol hydrochloride 5.0 mg/mL, tacrolimus monohydrate 0.5 mg/mL, ursodeoxycholic acid 20.0 mg/mL, and vancomycin hydrochloride 25.0 mg/mL. Suspensions were compounded with raw powders, except for mercaptopurine, pyrazinamide, and sotalol hydrochloride, which were made from commercial tablets. Stability was assessed by measuring the percentage recovery at 0 (baseline), 60 days, and 90 days after compounding for suspensions made with raw powders, which were stored at 2ÅãC to 8ÅãC. The stability of tablets, which were stored at 2ÅãC to 8ÅãC and 20ÅãC to 25ÅãC, was assessed by measuring the percentage recovery at 0 (baseline), 7 days, 14 days, 30 days, 60 days, and 90 days. Active pharmaceutical ingredients quantification was performed by ultraviolet high-performance liquid chromatography via a stability-indicating method. Given the percentage of recovery of the active pharmaceutical ingredients within the suspensions, the beyond-use date of the final products (active pharmaceutical ingredients + vehicle) was at least 90 days for all suspensions in the conditions tested. This suggests that SyrSpend SF PH4 is suitable for compounding active pharmaceutical ingredients from different pharmacological classes.
Asunto(s)
Baclofeno/química , Carvedilol/química , Hidroclorotiazida/química , Mercaptopurina/química , Metadona/química , Oseltamivir/química , Vehículos Farmacéuticos/química , Fenobarbital/química , Propranolol/química , Sotalol/química , Espironolactona/química , Almidón/química , Tacrolimus/química , Ácido Ursodesoxicólico/química , Vancomicina/química , Administración Oral , Baclofeno/administración & dosificación , Carvedilol/administración & dosificación , Composición de Medicamentos , Estabilidad de Medicamentos , Hidroclorotiazida/administración & dosificación , Concentración de Iones de Hidrógeno , Mercaptopurina/administración & dosificación , Metadona/administración & dosificación , Oseltamivir/administración & dosificación , Soluciones Farmacéuticas , Fenobarbital/administración & dosificación , Propranolol/administración & dosificación , Pirazinamida/administración & dosificación , Sotalol/administración & dosificación , Espironolactona/administración & dosificación , Suspensiones , Tacrolimus/administración & dosificación , Temperatura , Factores de Tiempo , Ácido Ursodesoxicólico/administración & dosificación , Vancomicina/administración & dosificaciónRESUMEN
BACKGROUND: Conventional local treatment for medullary osteomyelitis (OM) includes insertion of antibiotic-loaded polymethylmethacrylate (PMMA) cement. Nevertheless, PMMA may delivery irregular concentration of antibiotic to surrounding tissue. We aimed to compare the in vitro antibacterial activity of Bioactive Glass (BAG) S53P4, which is a compound showing local antibacterial activity, to that of antibiotic-loaded PMMA against multidrug resistant bacteria from OM isolates. METHODS: We studied convenience samples of multidrug resistant (MDR) microorganisms obtained from patients presenting OM and prosthetic joint infection (PJI). Mixtures containing tryptic soy broth (TSB) and inert glass beads (2 mm), BAG-S53P4 granules (0.5-0.8 mm and < 45 mm) and Gentamicin or Vancomycin-loaded PMMA beads were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MR-CoNS), Pseudomonas aeruginosa or Klebsiella pneumoniae isolates. Glass beads (2.0 mm) were used as a control. Antibacterial activity was evaluated by means of time-kill curve, through seeding the strains on blood agar plates, and subsequently performing colony counts after 24, 48, 72, 96, 120 and 168 h of incubation. Differences between groups were evaluated by means of two-way analysis of variance (ANOVA) and Bonferroni's t test. RESULTS: Inhibition of bacterial growth started soon after 48 h of incubation, reached zero CFU/ml between 120 and 168 h of incubation for both antibiotic-loaded PMMA and BAG S53P4 groups, in comparison with inert glass (p < 0.05). No difference regarding time-kill curves between antibiotic-loaded PMMA and BAG S53P4 was observed. CONCLUSIONS: BAG S53P4 presented antibacterial properties as much as antibiotic-loaded PMMA for MDR bacteria producing OM and PJI.
Asunto(s)
Antibacterianos/química , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Vidrio/química , Artropatías/patología , Osteomielitis/tratamiento farmacológico , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Cementos para Huesos , Portadores de Fármacos/química , Femenino , Gentamicinas/química , Gentamicinas/farmacología , Gentamicinas/uso terapéutico , Humanos , Artropatías/microbiología , Artropatías/cirugía , Prótesis Articulares , Klebsiella pneumoniae/efectos de los fármacos , Masculino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Osteomielitis/microbiología , Osteomielitis/patología , Polimetil Metacrilato/química , Pseudomonas aeruginosa/efectos de los fármacos , Vancomicina/química , Vancomicina/farmacología , Vancomicina/uso terapéuticoRESUMEN
Therapeutic monitoring of the antibiotic vancomycin is important to achieve specific plasma concentration and prevent toxic effects. Several assays have been described for vancomycin determination in clinical practice, but high-performance liquid chromatography is still considered the gold standard for the quantification of vancomycin. In this study, we developed a new and rapid high-performance liquid chromatography method requiring 50 µL of plasma for the quantification of vancomycin. Acetonitrile was used for processing plasma by protein precipitation (1:2.5). Isocratic chromatographic analysis was carried out on a C18 silica-based (2.7 µm) column with the mobile phase containing 20 mM ammonium acetate/formic acid buffer (pH 4.0):methanol 88:12 (v/v). A diode array detector was used for UV detection at 240 nm. This method was validated according to the Brazilian Health Surveillance Agency legislation and International Conference on Harmonization guidelines. The measurement range was 1-100 µg/mL, analysis time was 8 min, and intermediate precision was <12%, supporting the present method as a fast, simple, and effective alternative for therapeutic monitoring of vancomycin.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Monitoreo de Drogas/métodos , Vancomicina/sangre , Adulto , Anciano , Estabilidad de Medicamentos , Femenino , Humanos , Límite de Detección , Modelos Lineales , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Vancomicina/química , Vancomicina/farmacocinéticaRESUMEN
INTRODUCTION: Polymeric nanoparticles are promising nanotechnology tools to fight pathogenic bacteria resistant to conventional antibiotics. OBJECTIVE: To synthesize polylactic acid nanoparticles loaded with ofloxacin and vancomycin, and to determine their antibacterial activity against Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA). MATERIALS AND METHODS: We synthesized ofloxacin or vancomycin loaded polylactic acid nanoparticles by the emulsification-solvent evaporation method, and characterized them by dynamic light scattering, laser Doppler electrophoresis and scanning electron microscopy. We evaluated in vitro antibacterial activity of ofloxacin- and vancomycin-loaded polylactic acid nanoparticles against E. coli O157:H7 and MRSA using the broth microdilution method. RESULTS: Ofloxacin- and vancomycin-loaded polylactic acid nanoparticles registered a positive surface charge density of 21 mV and an average size lower than 379 nm. In vitro minimum inhibitory concentration (MIC50) of ofloxacin-polylactic acid nanoparticles was 0,001 µg/ml against E. coli O157:H7, i.e., 40 times lower than the free ofloxacin (MIC50: 0.04 µg/ml), indicating enhanced antibacterial activity while the in vitro MIC50 of vancomycin-polylactic acid nanoparticles was 0,005 µg/ml against MRSA, i.e., 100 times lower than that of free vancomycin (MIC50: 0.5 µg/ml). CONCLUSION: Polylactic acid nanoparticles loaded with ofloxacin and vancomycin showed a higher antibacterial activity. Polymeric nanoparticles are a possible alternative for drug design against pathogenic bacterial strains of public health interest.
Asunto(s)
Antibacterianos/farmacología , Escherichia coli O157/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Nanopartículas/química , Ofloxacino/farmacología , Poliésteres/síntesis química , Vancomicina/farmacología , Antibacterianos/química , Ofloxacino/química , Poliésteres/química , Vancomicina/químicaRESUMEN
Resumen Introducción: Las nanopartículas poliméricas constituyen una herramienta nanotecnológica que podría ayudar a combatir los microorganismos patógenos que han desarrollado resistencia a los antibióticos convencionales. Objetivo: Sintetizar nanopartículas de ácido poliláctico cargadas con ofloxacina y vancomicina, y determinar su actividad antibacteriana frente a Escherichia coli O157:H7 y Staphylococcus aureus resistente a la meticilina (SARM). Materiales y métodos: Las nanopartículas de ácido poliláctico cargadas con ofloxacina y vancomicina se sintetizaron utilizando el método de emulsión y evaporación de solvente. Se caracterizaron mediante dispersión de luz en modo dinámico, electroforesis Doppler con láser y microscopía electrónica de barrido (S-TEM). Se evaluó la actividad antibacteriana in vitro de las nanopartículas de ácido poliláctico con ofloxacina contra E. coli O157:H7 y nanopartículas de ácido poliláctico con vancomicina contra SARM, mediante el método de microdilución en caldo. Resultados: Se obtuvieron nanopartículas poliméricas con tamaños inferiores a 379 nm y carga superficial positiva de hasta 21 mV. Las nanopartículas cargadas con ofloxacina presentaron una concentración inhibitoria mínima (CIM50) de 0,001 μg/ml frente a E. coli O157:H7, valor 40 veces menor que la concentración de antibiótico libre necesaria para lograr el mismo efecto (CIM50=0,04 μg/ml). Para SARM, las nanopartículas mejoraron la potencia farmacológica in vitro de la vancomicina al exhibir una MIC50 de 0,005 μg/ml, comparada con la de 0,5 μg/ml del antibiótico libre. Conclusiones: Se mejoró el efecto antibacteriano de la ofloxacina y la vancomicina incorporadas en la matriz polimérica de ácido poliláctico. Las nanopartículas poliméricas constituirían una alternativa para el control de cepas bacterianas de interés en salud pública.
Abstract Introduction: Polymeric nanoparticles are promising nanotechnology tools to fight pathogenic bacteria resistant to conventional antibiotics. Objective: To synthesize polylactic acid nanoparticles loaded with ofloxacin and vancomycin, and to determine their antibacterial activity against Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA). Materials and methods: We synthesized ofloxacin or vancomycin loaded polylactic acid nanoparticles by the emulsification-solvent evaporation method, and characterized them by dynamic light scattering, laser Doppler electrophoresis and scanning electron microscopy. We evaluated in vitro antibacterial activity of ofloxacin- and vancomycin-loaded polylactic acid nanoparticles against E. coli O157:H7 and MRSA using the broth microdilution method. Results: Ofloxacin- and vancomycin-loaded polylactic acid nanoparticles registered a positive surface charge density of 21 mV and an average size lower than 379 nm. In vitro minimum inhibitory concentration (MIC50) of ofloxacin-polylactic acid nanoparticles was 0,001 μg/ml against E. coli O157:H7, i.e., 40 times lower than the free ofloxacin (MIC50: 0.04 μg/ml), indicating enhanced antibacterial activity while the in vitro MIC50 of vancomycin-polylactic acid nanoparticles was 0,005 μg/ml against MRSA, i.e., 100 times lower than that of free vancomycin (MIC50: 0.5 μg/ml). Conclusion: Polylactic acid nanoparticles loaded with ofloxacin and vancomycin showed a higher antibacterial activity. Polymeric nanoparticles are a possible alternative for drug design against pathogenic bacterial strains of public health interest.
Asunto(s)
Poliésteres/síntesis química , Vancomicina/farmacología , Ofloxacino/farmacología , Pruebas de Sensibilidad Microbiana/métodos , Escherichia coli O157/química , Nanopartículas/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Antibacterianos/farmacología , Poliésteres/química , Vancomicina/química , Ofloxacino/química , Antibacterianos/químicaRESUMEN
Sensitized photooxidation processes in the presence of natural pigments may provide an alternative to antibiotics degradation since these compounds are transparent to natural light irradiation, therefore, they can be degraded by the action of photosensitizers which absorb light and produce highly reactive species, especially those derived from molecular oxygen (ROS). Most antibiotics used currently belong to a group of pharmaceutical substances that have been considered a new type of contaminants due to their persistence and bioaccumulation in the environment. OBJECTIVE: In this context, we decided to investigate the kinetic and mechanistic aspects of Vancomycin (Vanco) photosensitized degradation in the presence of the natural pigment Riboflavin (Vitamin B2, Rf) and the artificial dye Rose Bengal (RB) for comparative purposes. METHODS: The study have been done by using Stationary photolysis, Laser flash photolysis, Time-resolved phosphorence detection of O2(1Δg) experiments and Bactericidal activity evaluation. The experiments were carried out in aqueous solution at different pH values in order to establish relationships between the structure of the compound and its susceptibility to ROS-mediated photooxidation. RESULTS: Experimental evidence indicates that in the presence of Rf there is considerable contribution of the radical-mediated mechanism, while in the presence of RB the photooxidation process occurs exclusively through O2(1Δg) and the reactivity to this excited species increases with increasing pH of the environment. DISCUSSION: The results obtained, have been shown that Rf can raise the photodegradation of Vanco by both the radical pathway and the O2(1Δg) mediated. Furthermore, the antibiotic is able to interact with the excited electronic states of Rf as well as O2(1Δg) generated by energy transfer between the excited triplet state of the photosensitizer and the oxygen ground state. The predominant mechanism for photodegradation of Vanco in the presence of the Rf is the radical via because of the considerable interaction with the excited triplet state of the photosensitizer demonstrated by laser flash photolysis experiments. Microbiological test on Staphylococcus aureus ATCC25923 showed that the bactericidal activity of the antibiotic on the strain studied was affected by the sensitized photodegradation process, suggesting that photoproducts generated eventually do not retain the bactericidal properties of the original antibiotic.
Asunto(s)
Riboflavina/química , Vancomicina/química , Antibacterianos/química , Luz , Fármacos Fotosensibilizantes/química , Especies Reactivas de Oxígeno/químicaRESUMEN
The aim of this work was to evaluate the perfomance of agar-gelatin (AG) composites and AG-containing 45S5 bioactive glass (BG) microparticles (AGBG) in relation to their water uptake capacity, sustained release of a drug over time, and antibacterial effects. The composites were fabricated by the gel-casting method. To impart the local drug release capacity, vancomycin hydrochloride (VC) was loaded in the composites in concentrations of 0.5 and 1 mg ml(-1). VC release was assessed in distilled water at 37 °C up to 72 h and quantified spectrophotometrically. The antibacterial activity of composites was evaluated by the inhibition zone test and the plate count method. The experiments were performed in vitro up to 48 h on three staphylococcus strains: Staphylococcus aureus ATCC29213, S. aureus ATCC6538 and Staphylococcus epidermidis ATCC12228. The results showed that the addition of BG to AG composites did not affect the degree of water uptake. The release of VC was significantly affected by the presence of BG. VC release was higher from AGBGVC films than from AGVC ones over prolonged incubation times. Bacterial inhibition zones were found around the composites. The halos were larger when the cells were put in contact with AGVC composites than when they were put in contact with AGBGVC ones. Nevertheless, the viable count method demonstrated that the composites inhibited Staphylococcus cell growth with no statistical differences. In conclusion, the addition of BG did not reflect an improvement in the parameters studied. On the other hand, composites loaded with VC would have a role in prophylaxis against bacterial infection.
Asunto(s)
Agar/química , Antibacterianos/química , Gelatina/química , Vancomicina/química , Calibración , Sistemas de Liberación de Medicamentos , Vidrio/química , Humanos , Ensayo de Materiales , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Espectrofotometría , Infecciones Estafilocócicas/tratamiento farmacológico , Staphylococcus aureus/efectos de los fármacos , Staphylococcus epidermidis/efectos de los fármacos , Agua/químicaRESUMEN
Bacterial infections are a leading cause of morbidity and mortality among solid organ transplant recipients. Over the last two decades, various multidrug-resistant (MDR) pathogens have emerged as relevant causes of infection in this population. Although this fact reflects the spread of MDR pathogens in health care facilities worldwide, several factors relating to the care of transplant donor candidates and recipients render these patients particularly prone to the acquisition of MDR bacteria and increase the likelihood of MDR infectious outbreaks in transplant units. The awareness of this high vulnerability of transplant recipients to infection leads to the more frequent use of broad-spectrum empiric antibiotic therapy, which further contributes to the selection of drug resistance. This vicious cycle is difficult to avoid and leads to a scenario of increased complexity and narrowed therapeutic options. Infection by MDR pathogens is more frequently associated with a failure to start appropriate empiric antimicrobial therapy. The lack of appropriate treatment may contribute to the high mortality occurring in transplant recipients with MDR infections. Furthermore, high therapeutic failure rates have been observed in patients infected with extensively-resistant pathogens, such as carbapenem-resistant Enterobacteriaceae, for which optimal treatment remains undefined. In such a context, the careful implementation of preventive strategies is of utmost importance to minimize the negative impact that MDR infections may have on the outcome of liver transplant recipients. This article reviews the current literature regarding the incidence and outcome of MDR infections in liver transplant recipients, and summarizes current preventive and therapeutic recommendations.
Asunto(s)
Infecciones Bacterianas/complicaciones , Infecciones Bacterianas/tratamiento farmacológico , Farmacorresistencia Bacteriana Múltiple , Trasplante de Hígado/efectos adversos , Antibacterianos/uso terapéutico , Proteínas Bacterianas/metabolismo , Enterobacteriaceae/metabolismo , Enterococcus/efectos de los fármacos , Humanos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa/metabolismo , Factores de Riesgo , Vancomicina/química , beta-Lactamasas/metabolismoRESUMEN
Glycidyl methacrylate (GMA) and acrylic acid (AAc) were separately grafted onto polypropylene (PP) monofilament sutures by means of pre-irradiation using a (60)Co γ-source, with the purpose of loading vancomycin via (i) covalent immobilization through the glycidyl groups of GMA and (ii) ionic interaction with AAc moieties. The effect of absorbed radiation dose, monomer concentration, temperature and reaction time on the grafting degree was evaluated in detail. GMA grafting ranged from 25% to 800% while the grafting yield of AAc onto PP could be tuned between 9% and 454%, at doses from 5 to 50 kGy and a dose rate 13.7 kGy/h. Grafting of GMA or AAc decreased the decomposition temperature and made the sutures swellable to a certain extent. GMA grafting led to a continuous, smooth and thick coating, which was suitable for immobilization of up to 1.9 µg vancomycin per gram. The immobilized vancomycin enabled a reduction in the Staphylococcus aureus CFU adhered to the suture surface. On the other hand, dried AAc-functionalized sutures exhibited a rough and cracked surface which was responsible for a minor increase in the coefficient of friction. PP-g-AAc sutures exhibited pH-dependent swelling and remarkably high capability to host vancomycin (up to 109.9 mg/g), particularly those with an intermediate degree of grafting. Some AAc-functionalized sutures were shown able to inhibit bacterial growth after successive challenges with fresh lawns. Therefore, tuning the yield of grafting of GMA or AAc may enable the preparation of drug-suture combination products that retain or release, respectively, antimicrobial agents.
Asunto(s)
Polímeros/química , Polipropilenos/química , Suturas , Vancomicina/administración & dosificación , Acrilatos/química , Adsorción , Antibacterianos/administración & dosificación , Antibacterianos/química , Antibacterianos/farmacología , Compuestos Epoxi/química , Fricción , Concentración de Iones de Hidrógeno , Metacrilatos/química , Staphylococcus aureus/efectos de los fármacos , Temperatura , Vancomicina/química , Vancomicina/farmacologíaRESUMEN
New smart surface-modified polypropylene (PP) was prepared for improving the loading and the sustained delivery of vancomycin and, thus, reducing the risk of biofilm formation when used as component of biomedical devices. Isothermal titration calorimetry (ITC) served for screening the most suitable monomers for grafting; the drug preferentially bonding to ionized acrylic acid (AAc). A net-PP-g-PNIPAAm-inter-net-PAAc was synthesized by first grafting and cross-linking of N-isopropylacrylamide onto PP films and then interpenetrating a second network by redox polymerization and cross-linking of AAc. PP-g-PAAc slabs were prepared by grafting AAc and, optionally, cross-linking. The amount and composition of grafted polymer (FTIR-ATR), morphology (SEM), temperature- and pH-responsiveness (swelling measurements), thermal behavior (DSC), friction coefficient (rheometry), drug loading and release rate, and effect against methicillin-resistant Staphylococcus aureus (MRSA) biofilms (modified robbins device) were evaluated. Grafting of AAc notably decreased the friction coefficient from 0.28+/-0.03 to 0.05+/-0.02 and enhanced the vancomycin loading (up to 2.5mg/cm(2)). Drug-loaded films showed a pH-dependent release rate, sustaining the release in pH 7.4 aqueous media at 37 degrees C for several hours. All drug-loaded films reduced biofilm formation by MRSA; the anti-biofilm effect being statistically significant (91.7% reduction, alpha<0.05) for PP-g-PAAc with the thinnest grafting layer.