RESUMO
Caseous lymphadenitis is a well-known disease caused by Corynebacterium pseudotuberculosis affecting small ruminants with small significance to human health because of its minor zoonotic potential. In both cases, few treatment options are available and conventional antimicrobial therapy is commonly refractory due to development of pyogranulomatous reactions, bringing great interest in discovering novel therapeutics for more suitable approaches. Dideoxynucleotides presented antibacterial action against various bacteria but were never described for C. pseudotuberculosis. Hypothesizing the antimicrobial action of 2',3'-dideoxiadenosine (ddATP) against C. pseudotuberculosis, we performed for the first time an investigation of its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the ATCC® 19,410 strain and a well-characterized clinical isolate of C. pseudotuberculosis. We also assessed potential synergism with penicillin. ddATP showed a growth delay effect for C. pseudotuberculosis at 2 µmol/mL and a MIC and MBC of 4 µmol/mL against the ATCC® 19,410 strain, but not for the clinical strain. An antimicrobial effect was observed when using concentrations lower than the MIC of ddATP associated with penicillin for both strains tested. Our data suggest the potential of nucleotide analogs, especially adenosine, and its combination with penicillin, as a possible novel treatment for C. pseudotuberculosis-induced infections, and contributes with knowledge regarding alternative drugs to treat C. pseudotuberculosis infections.
Assuntos
Infecções por Corynebacterium , Corynebacterium pseudotuberculosis , Linfadenite , Humanos , Penicilinas/farmacologia , Infecções por Corynebacterium/microbiologia , Linfadenite/microbiologia , Antibacterianos/farmacologiaRESUMO
Staphylococcus aureus remains a pathogen of high concern in public health programs worldwide due to antibiotic resistance and emergence of highly virulent strains. Many phytochemicals have demonstrated activity against S. aureus and other Gram-positive bacteria, but the minimum inhibitory concentration (MIC) values comparable to commonly used antibiotics are needed. In the present study, bio-guided fractionation of the ethanol extract of seeds of Mammea americana L. (Calophyllaceae) throughout the antibacterial activity, against S. aureus strains that are sensitive and resistant to methicillin, led to the isolation of four coumarins identified as mammea B/BA, mammea B/BC, mammea A/AA cyclo D and mammea A/AA cyclo F, and a mixture of mammea B/BA cyclo F plus mammea B/BD cyclo F. The extract inhibited the growth of S. aureus with MIC values of 2-4 µg/ml and Mammea B/BA (MaBBA) presented MIC values in a range between 0.5 and 1.0 µg/ml in six methicillin-sensitive strains and eight methicillin-resistant strains evaluated. We consider MaBBA the most potent of all mammea coumarins reported to date, according to the literature review carried out at the time of writing of this article. Toxicity assessment in vivo against the nematode Caenorhabditis elegans and in vitro against human fibroblasts of the extract and the compound MaBBA indicated that both had low toxicity.
RESUMO
SUMMARY Purpose: We present a new Colombian product researched and developed by Seven Scientific Foundation, which has been very useful for the removal of the carious tissue in patients who have used this innovative product. Methods: We used a chemical-mechanical removal of dental caries. This product is made with 10% papain which is the active principle and works as a debriding agent, as well as being a bacteriostatic, bactericidal and anti-inflammatory agent; and also contain dragon's blood (Croton lechleri) sap which is an effective as analgesic/anti-inflammatory and especially as a healing agent. In this article, we present a case study of a patient, whose dental carious tissue was removed, using the dental new product. Description of the case report: In this article, we present a case study of a patient, whose dental carious tissue has been removed, using the new dental product, therefore this innovative technique of removal of the atraumatic carious tissue. Conclusions: This method is useful as it is a minimally invasive technique, without requiring the use of local anesthesia, or the additional use of dental instruments. It is used in the Colombian population of all ages and does not generate side effects in people who have used it so far.
RESUMEN Propósito: se investigó y desarrolló un nuevo producto dental el cual ha sido muy útil para la remoción del tejido carioso en los pacientes colombianos que han utilizado este innovador producto para la remoción químico-mecánica de las caries dentales. Métodos: Este producto está hecho a base de papaína al 10 % el cual es el principio activo y funciona como un agente debridante lo cual cicatriza el tejido removido, además de ser un agente bacteriostático, bactericida y antiinflamatorio. Descripción de reporte de caso: en este artículo se presenta un estudio de caso de un paciente al cual se le removió el tejido carioso dental. Conclusiones: Por lo tanto, esta técnica innovadora de remoción del tejido carioso atraumático resulta útil por ser una técnica mínimamente invasiva, sin requerir el uso de anestesia local al tejido afectado ni el uso adicional de instrumentos dentales. Se utiliza en la población colombiana de todas las edades y no genera efectos colaterales en las personas que lo han utilizado hasta el momento.
RESUMO
In this work, composites of high density polyethylene (HDPE) with chitosan were prepared by melt compounding in a laboratory internal mixer. Maleic anhydride grafted HDPE (PE-g-MA) in a concentration up to 25 phr was used as a compatibilizer to enhance the dispersing effect of chitosan in the HDPE matrix. The degree of crystallinity was investigated by X-ray diffraction (XRD) and the thermal properties were analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TG). The morphology was investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The integrity of composites was evaluated by mechanical properties and antibacterial properties were assessed against Escherichia coli (DH5a). Neither crystallinity nor HDPE's melting parameters changed upon addition of chitosan and PE-g-MA. Chitosan aggregates were observed, which were dispersed upon addition of PE-g-MA, which also provided improved mechanical performance. Chitosan significantly improved the bacteriostatic effect of HDPE compounds preventing bacteria to colonize thus reducing the number of viable colony-forming units (CFU). This study revealed that HDPE/chitosan composites could be obtained by melt compounding, at lower cost and additionally having antibacterial properties, which might provide a new formulation option for developing antimicrobial film for food packaging.
RESUMO
This work aimed to evaluate the effects of CasuL on growth and viability of 15 mastitis isolates from cows and goats, to determine the synergistic potential between CasuL and antibiotics, and to investigate the effects on bacterial ultrastructure and antibiofilm activity. The lectin inhibited the growth of Staphylococcus isolates from either bovine (Ssp6PD and Sa) or caprine (Ssp5D and Ssp01) mastitis. The minimal inhibitory concentrations were ranged from 3.75 to 15 µg/ml. Synergistic effect was observed for CasuL-tetracycline against Sa and Ssp6PD and CasuL-ampicillin against Ssp01. No structural damage was observed under the scanning electron microscope in CasuL treatments. Flow cytometry analysis using thiazol orange and propidium iodide demonstrated that CasuL was unable to reduce the cell viability of the isolates tested. At sub-inhibitory concentrations, CasuL reduced biofilm formation by the isolates Sa and Ssp5D. However, CasuL-tetracycline and CasuL-ampicillin combinations inhibited biofilm formation by Ssp6PD and Ssp01, respectively. In conclusion, CasuL is a bacteriostatic and antibiofilm agent against some mastitis isolates and displayed a synergistic potential when used in combination with either ampicillin (against one isolate) or tetracycline (against two isolates). The results stimulate the evaluation of CasuL for the treatment of mastitis, particularly when used in conjunction with antibiotics.
Assuntos
Antibacterianos/farmacologia , Doenças dos Bovinos/microbiologia , Fabaceae/química , Doenças das Cabras/microbiologia , Lectinas/farmacologia , Mastite/veterinária , Staphylococcus/efeitos dos fármacos , Animais , Antibacterianos/isolamento & purificação , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Bovinos , Sinergismo Farmacológico , Cabras , Lectinas/isolamento & purificação , Mastite/microbiologia , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus/crescimento & desenvolvimento , Staphylococcus/isolamento & purificaçãoRESUMO
In the current study, the size and surface of ZnO nanoparticle (ZnO NP) suspensions and powders were finely controlled to evaluate their influence on the ZnO antibacterial activity against Staphylococcus aureus and Escherichia coli. The ZnO NP were prepared by the sol-gel method with different reaction times for NP size control and followed by the addition of (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as a surface modifier. The ZnO NP were characterized by different techniques and the antibacterial activity was assessed through the minimum inhibitory concentration assay (MIC), minimum bactericidal concentration assay (MBC) and scanning electron microscopy (SEM). The ZnO NP exhibited significant antibacterial activity against Staphylococcus aureus. The NP size highly influenced the antibacterial activity, which increased with decreasing particle size. The small ZnO NP presented bactericidal activity whereas the largest showed bacteriostatic activity. The use of GPTMS, in general, led to increase of MIC and MBC. The formation of holes in the cell wall of Staphylococcus aureus was evidenced by SEM after contact between the bacteria and ZnO NP. The cytotoxicity assay showed that ZnO NP did not cause a loss of cell viability in the human keratinocyte cell line (HaCat) at the maximum concentration assessed. Thus, this study indicated that 5 nm ZnO NP modified by GPTMS has great potential for use as an inorganic antibacterial material.
Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Nanopartículas/química , Staphylococcus aureus/efeitos dos fármacos , Óxido de Zinco/farmacologia , Antibacterianos/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Propriedades de Superfície , Óxido de Zinco/químicaRESUMO
Relationships among physicochemical properties, the chemical structure and antibacterial activity of sulfonamides have not been completely explicated yet. Nevertheless, from a therapeutics and prodrugs design point of view, a substituent group can modify the electronic structure, the physicochemical features and chemical reactivity which are critical for the biological activity. In this work, we analyze the substituent effects on the physicochemical properties, toxicity, chemical reactivity and its relation with the bacteriostatic activity of selected sulfonamides by means of DFT-M06-2X calculations in aqueous solution, using quantum chemical and docking descriptors. A correlation between the theoretical acidity and the pKa experimental values has been found. The more active sulfonamides have a larger acidity. The acidity increases with electron-withdrawing substituents. The main reactivity takes place on N4 atoms linked to aromatic ring, and in the SO2NH moiety, which are influenced by substituents. Docking descriptors showed binding affinities between sulfonamides and target receptor, the dihydropteroate synthase (DHPS).
Assuntos
Antibacterianos/química , Modelos Moleculares , Sulfonamidas/química , Algoritmos , Antibacterianos/toxicidade , Simulação por Computador , Ligação de Hidrogênio , Estrutura Molecular , Eletricidade Estática , Relação Estrutura-Atividade , Sulfonamidas/toxicidadeRESUMO
The aim of this work was to evaluate the antimicrobial activity of plant extracts Ocotea silvestris Vattimo-Gil and Ocotea diospyrifolia (Meisn.) Mez against 10 serotypes Salmonella enterica of poultry origin of the highest incidence in the western region of Paraná, as well as to perform the phytochemical screening of the compounds of the two species. After obtaining the aqueous extract and the organic extracts (ethyl alcohol, ethyl acetate and hexane) was determined Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) by technique microdilution broth. Phytochemical prospecting performed according to qualitative methodology of precipitation and colorimetry. The extracts presented inhibitory and bactericidal activity in different concentrations (200 to 25 mg.mL-1) against the serotypes of Salmonella, varying according to the solvent extractor. The ethyl acetate extract presented the best results, followed by the alcoholic, aqueous and hexane extract. It is noteworthy that studies of antimicrobial activity with vegetable extract within the genus Ocotea are scarce, however, the Lauraceae family presents significant biological activities, mainly related to its essential oils. Phytochemical prospecting detected the presence of steroids and alkaloids in both Ocotea species, which may justify the antimicrobial potential found for Salmonella serotypes. It is concluded that these plants represent an alternative for the control of Salmonella in the poultry sector, reflecting a new perspective for studies with natural products.(AU)
O objetivo deste trabalho foi avaliar a atividade antimicrobiana dos extratos vegetais de Ocotea silvestris Vattimo-Gil e Ocotea diospyrifolia (Meisn.) Mez frente a 10 sorotipos de Salmonella enterica de origem avícola de maior incidência na região Oeste do Paraná, bem como realizar a triagem fitoquímica dos compostos de Ocotea silvestris Vattimo-Gil e Ocotea diospyrifolia (Meisn.). Após a obtenção do extrato aquoso e dos extratos orgânicos (álcool etílico, acetato de etila e hexano) foram determinadas a concentração inibitória mínima (MIC) e a concentração bactericida mínima (MBC) por meio da técnica de microdiluição em caldo. A prospecção fitoquímica foi realizada de acordo com metodologia qualitativa de precipitação e colorimetria. Os extratos apresentaram atividade inibitória e bactericida em diferentes concentrações (200 a 25 mg.mL-1) frente aos sorotipos de Salmonella, variando de acordo com o solvente extrator. O extrato acetato de etila apresentou os melhores resultados, seguido pelo extrato alcoólico, aquoso e hexânico. Ressalta-se que estudos de atividade antimicrobiana com extrato vegetais dentro do gênero Ocotea são escassos, contudo, a família Lauraceae apresenta significativas atividades biológicas, principalmente relacionadas aos seus óleos essenciais. A prospecção fitoquímica detectou a presença de esteróides e alcalóides em ambas as espécies de Ocotea, podendo justificar o potencial antimicrobiano encontrado para os sorotipos de Salmonella. Conclui-se que estas plantas representam uma alternativa para o controle de Salmonella no setor avícola, refletindo uma nova perspectiva para estudos com produtos naturais.(AU)
Assuntos
Animais , Ocotea , Sorogrupo , SalmonellaRESUMO
The aim of this work was to evaluate the antimicrobial activity of plant extracts Ocotea silvestris Vattimo-Gil and Ocotea diospyrifolia (Meisn.) Mez against 10 serotypes Salmonella enterica of poultry origin of the highest incidence in the western region of Paraná, as well as to perform the phytochemical screening of the compounds of the two species. After obtaining the aqueous extract and the organic extracts (ethyl alcohol, ethyl acetate and hexane) was determined Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) by technique microdilution broth. Phytochemical prospecting performed according to qualitative methodology of precipitation and colorimetry. The extracts presented inhibitory and bactericidal activity in different concentrations (200 to 25 mg.mL-1) against the serotypes of Salmonella, varying according to the solvent extractor. The ethyl acetate extract presented the best results, followed by the alcoholic, aqueous and hexane extract. It is noteworthy that studies of antimicrobial activity with vegetable extract within the genus Ocotea are scarce, however, the Lauraceae family presents significant biological activities, mainly related to its essential oils. Phytochemical prospecting detected the presence of steroids and alkaloids in both Ocotea species, which may justify the antimicrobial potential found for Salmonella serotypes. It is concluded that these plants represent an alternative for the control of Salmonella in the poultry sector, reflecting a new perspective for studies with natural products.
O objetivo deste trabalho foi avaliar a atividade antimicrobiana dos extratos vegetais de Ocotea silvestris Vattimo-Gil e Ocotea diospyrifolia (Meisn.) Mez frente a 10 sorotipos de Salmonella enterica de origem avícola de maior incidência na região Oeste do Paraná, bem como realizar a triagem fitoquímica dos compostos de Ocotea silvestris Vattimo-Gil e Ocotea diospyrifolia (Meisn.). Após a obtenção do extrato aquoso e dos extratos orgânicos (álcool etílico, acetato de etila e hexano) foram determinadas a concentração inibitória mínima (MIC) e a concentração bactericida mínima (MBC) por meio da técnica de microdiluição em caldo. A prospecção fitoquímica foi realizada de acordo com metodologia qualitativa de precipitação e colorimetria. Os extratos apresentaram atividade inibitória e bactericida em diferentes concentrações (200 a 25 mg.mL-1) frente aos sorotipos de Salmonella, variando de acordo com o solvente extrator. O extrato acetato de etila apresentou os melhores resultados, seguido pelo extrato alcoólico, aquoso e hexânico. Ressalta-se que estudos de atividade antimicrobiana com extrato vegetais dentro do gênero Ocotea são escassos, contudo, a família Lauraceae apresenta significativas atividades biológicas, principalmente relacionadas aos seus óleos essenciais. A prospecção fitoquímica detectou a presença de esteróides e alcalóides em ambas as espécies de Ocotea, podendo justificar o potencial antimicrobiano encontrado para os sorotipos de Salmonella. Conclui-se que estas plantas representam uma alternativa para o controle de Salmonella no setor avícola, refletindo uma nova perspectiva para estudos com produtos naturais.
Assuntos
Animais , Ocotea , Salmonella , SorogrupoRESUMO
Pseudomonas aeruginosa es un bacilo Gram negativo no fermentador de glucosa comúnmente aislado en infecciones nosocomiales. El incremento de la resistencia a los antibióticos y la participación de este microorganismo en patologías que cursan con formación de biopelículas da como resultado la falla usual de los antimicrobianos, por lo que resulta interesante estudiar el extracto etanólico de propóleos (EEP) como alternativa terapéutica frente a este patógeno oportunista. En este sentido, el objetivo principal del estudio fue evaluar el efecto del EEP sobre Pseudomonas aeruginosa en estado planctónico y sésil. El estudio se enmarcó en una investigación de tipo descriptiva, cuasi-experimental. Se determinó la concentración mínima inhibitoria (CMI) y bactericida (CMB) en estado planctónico por el método de macrodilución en tubos y en estado sésil por microdilución sobre biopelículas formadas en placas de poliestireno. Los resultados mostraron que el EEP, posee actividad bacteriostática parcial pero no total a 4% y actividad bactericida a 8% sobre P. aeruginosa en estado planctónico. Mientras que en estado sésil no hubo efecto bacteriostático ni bactericida. Se concluye que el EEP del Edo. Táchira Venezuela es efectivo frente a P. aeruginosa en estado planctónico pero no tiene actividad antimicrobiana sobre biopelículas formadas por la misma especie.
Pseudomonas aeruginosa is a glucose non-fermenting Gram-negative bacillus that is commonly isolated in nosocomial infections. The usual antimicrobials failure is the result of the increase in antibiotics resistance and this microorganisms involvement in pathologies with biofilm formation. Therefore, the ethanol extract of propolis becomes an interesting subject of study as a therapeutic alternative against this opportunist pathogen. In this regard, the main objective of this investigation was to evaluate the effect of ethanol extract of propolis (EEP) over Pseudomonas aeruginosa in planktonic and sessile state. This research was categorized as a descriptive quasi-experimental type of investigation. It was determined the minimum inhibitory (MIC) and bactericide (MBC) concentration by the macrodilution tubes method in planktonic state, and the microdilution over biofilms formed on polystyrene plates in sessile state. The results showed that whereas there wasnt a bacteriostatic or bactericide effect in sessile state, the EEP possesses 4% of non total but partial bacteriostatic activity and 8% of bactericide activity over P. aeruginosa in planktonic state. It concludes that the EEP of the Venezuelan state of Táchira is effective against P. aeruginosa in planktonic state but it wont have antimicrobial activity over biofilms formed by the same species.
RESUMO
Listeria monocytogenes es un patógeno causante de enfermedades alimentarias. En la búsqueda de controlar su propagación utilizando sustancias naturales se planteó el objetivo de mostrar si el extracto etanólico foliar de neem (Azadirachta Indica A. Juss.) tiene efecto antimicrobiano sobre L. monocytogenes ICTA-12446. El extracto se obtuvo a partir de hojas de neem sometidas a secado por 8 días, se redujeron de tamaño mecánicamente, se sometieron a maceración en frío por 3 días usando etanol 96% en recipientes ámbar, se filtró y concentró en rota evaporador. Se estandarizó el concentrado con dimetilsulfóxido (DMSO) a una concentración de 60 mg/L. Listeria monocytogenes ICTA-12446, fue inoculado en caldo nutriente junto con soluciones del extracto a diferentes concentraciones (20, 30, 40, 50 y 60 mg/L), se emplearon tiempos de contacto (2.5, 5, 10 y 15 minutos). Cumplido cada tiempo se realizaron diluciones seriadas e inocularon en agar nutritivo por extensión durante 24 h a 37ºC. Se efectuó el recuento en Unidades Formadoras de Colonias UFC. Al comparar las concentraciones del extracto se evidencia entre 20 y 60 mg/mL diferencia significativa, mientras que en 30, 40 y 50 mg/mL un comportamiento similar. Al contrastar tiempos de contacto, se observa que entre el tiempo 2.5 min y los restantes un p=0,03. El tiempo mínimo donde existió inhibición fue 2.5 minutos, y concentración mínima inhibitoria de 20 mg/mL. Los cuatro tiempos de contacto arrojan porcentajes de inhibición microbiana de 100% al emplear 60mg/mL. Se concluye que el extracto etanólico foliar de neem posee un efecto inhibitorio sobre Listeria monocytogenes(AU)
Listeria monocytogenes is a pathogen causing foodborne illness. In seeking to control its spread using natural substances in order to show if the leaf ethanol extract of neem (Azadirachta indica A. Juss) has antimicrobial effect on L. monocytogenes ICTA-12446, was proposed. The extract was obtained from neem leaves, which was subjected to drying for 8 days. It was reduced in size mechanically, and subjected to cold soak for 3 days, using 96% ethanol in amber vessels, filtered and concentrated in rot evaporator. Concentrated was solubilized with dimethylsulfoxide (DMSO) and standarized to achieve a concentration of 60 mg/mL Listeria monocytogenes was inoculated in nutrient broth with extract solutions at different concentrations (20, 30, 40, 50 and 60mg/mL), four contact times (2.5, 5, 10 and 15 minutes) were used. Completed each time it was diluted and inoculated on nutrient agar by extension for 24h at 37ºC. The count of Colony Forming Units UFC was taking. Comparing the concentrations of the extract between 20 and 60mg /mL significant difference was appreciate, while 30, 40 and 50 mg/mL show a similar behavior. Contrasting contact times observed between time 2.5 min and the remaining p = 0.03. The minimum time where there was some kind of inhibition was 2.5 minutes, and minima inhibitory concentration of 20mg/mL. The four contact times yield microbial inhibition percentages of 100% by using 60mg/L. It is concluded that ethanol extract of neem leaf has an inhibitory effect on L. monocytogenes(AU)
Assuntos
Humanos , Masculino , Feminino , Bacilos Gram-Negativos Anaeróbios Facultativos/fisiologia , Azadirachta/fisiologia , Etanol/química , Manipulação de Alimentos/métodos , Listeria monocytogenes , Bacteriologia , Efeitos Fisiológicos de DrogasRESUMO
Three α-ketoaldehydes, potentially present in high fructose agave syrups (HFASs) as intermediates of the Maillard reaction, were determined. A previously reported HPLC-FLD procedure based on pre-column derivatisation with 4-methoxy-o-phenylenediamine was adopted, yielding the method quantification limits 0.11 mg/kg, 0.10mg/kg, 0.09 mg/kg for glyoxal, methylglyoxal (MGo) and diacetyl, respectively. The obtained results revealed high concentrations of methylglyoxal in HFASs (average 102 ± 91 mg/kg, range 15.6-315 mg/kg) as compared to commercial Mexican bee honeys or corn syrups. Hydrogen peroxide was generated in all HFASs upon dilution, yet to less extent than in bee honeys. HFASs presented bacteriostatic activity against Bacillus subtilis and Escherichia coli; catalase addition had minimum effect on the assay results in syrups with elevated MGo. Principal component analysis revealed direct association between growth inhibition and MGo. It is concluded that elevated concentration of MGo in HFASs is at least in part responsible for their non-peroxide bacteriostatic activity.
Assuntos
Agave/química , Cromatografia Líquida de Alta Pressão/métodos , Frutose/química , Mel/análise , Animais , AbelhasRESUMO
Agriculture uses a huge variety and quantity of chemicals. If, on one hand, the goal is to increase productivity, on the other hand these products contaminate aquatic environments. Among these products, herbicides deserve greater attention in relation to contamination of aquatic environments due to their extensive use to weed control. This study was carried out because the effects of these molecules on aquatic microorganisms such as Escherichia coli, is still unclear. Using microdilution plate assays, Escherichia coli were exposed to various commercial formulations of herbicides widely used in Brazil. The herbicide paraquat was the only one able to prevent the growth of Escherichia coli and is characterized as bacteriostatic.
A agricultura utiliza uma enorme variedade de produtos químicos, e se por um lado a meta é aumentar a produtividade, por outro lado estes produtos contaminam ambientes aquáticos. Entre estes produtos, herbicidas merecem maior atenção em relação à contaminação de ecossistemas aquáticos, devido a seu amplo emprego para controlar plantas daninhas. Este estudo foi realizado porque os efeitos destas moléculas em micro-organismos aquáticos, tais como Escherichia coli, ainda são pouco estudados. Através de ensaios de microdiluição, E. coli foi exposta a várias formulações comerciais de herbicidas amplamente utilizados no Brasil e foi verificado que o herbicida paraquat foi o único capaz de impedir o crescimento de E. coli, caracterizando-se assim como bacteriostático.
Assuntos
Escherichia coli/efeitos dos fármacos , Herbicidas/toxicidade , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Paraquat/toxicidade , Fatores de TempoRESUMO
Agriculture uses a huge variety and quantity of chemicals. If, on one hand, the goal is to increase productivity, on the other hand these products contaminate aquatic environments. Among these products, herbicides deserve greater attention in relation to contamination of aquatic environments due to their extensive use to weed control. This study was carried out because the effects of these molecules on aquatic microorganisms such as Escherichia coli, is still unclear. Using microdilution plate assays, Escherichia coli were exposed to various commercial formulations of herbicides widely used in Brazil. The herbicide paraquat was the only one able to prevent the growth of Escherichia coli and is characterized as bacteriostatic.
A agricultura utiliza uma enorme variedade de produtos químicos, e se por um lado a meta é aumentar a produtividade, por outro lado estes produtos contaminam ambientes aquáticos. Entre estes produtos, herbicidas merecem maior atenção em relação à contaminação de ecossistemas aquáticos, devido a seu amplo emprego para controlar plantas daninhas. Este estudo foi realizado porque os efeitos destas moléculas em micro-organismos aquáticos, tais como Escherichia coli, ainda são pouco estudados. Através de ensaios de microdiluição, E. coli foi exposta a várias formulações comerciais de herbicidas amplamente utilizados no Brasil e foi verificado que o herbicida paraquat foi o único capaz de impedir o crescimento de E. coli, caracterizando-se assim como bacteriostático.
RESUMO
Antihistaminics are widely used for various indications during microbial infection. Hence, this paper investigates the antimicrobial activities of 10 antihistaminics belonging to both old and new generations using multiresistant Gram-positive and Gram-negative clinical isolates. The bacteriostatic activity of antihistaminics was investigated by determining their MIC both by broth and agar dilution techniques against 29 bacterial strains. Azelastine, cyproheptadine, mequitazine and promethazine were the most active among the tested drugs. Diphenhydramine and cetirizine possessed weaker activity whereas doxylamine, fexofenadine and loratadine were inactive even at the highest tested concentration (1 mg/ml). The MIC of meclozine could not be determined as it precipitated with the used culture media. The MBC values of antihistaminics were almost identical to the corresponding MIC values. The bactericidal activity of antihistaminics was also studied by the viable count technique in sterile saline solution. Evident killing effects were exerted by mequitazine, meclozine, azelastine and cyproheptadine. Moreover, the dynamics of bactericidal activity of azelastine were studied by the viable count technique in nutrient broth. This activity was found to be concentration-dependant. This effect was reduced on increasing the inoculum size while it was increased on raising the pH. The post-antimicrobial effect of 100 fg/ml azelastine was also determined and reached up to 3.36 h.
Assuntos
Humanos , Antagonistas dos Receptores Histamínicos H1/análise , Antagonistas dos Receptores Histamínicos H1/farmacologia , Resistência Microbiana a Medicamentos , Técnicas In Vitro , Meios de Cultura/análise , Meios de Cultura/farmacologia , Métodos , Métodos , Usos TerapêuticosRESUMO
Antihistaminics are widely used for various indications during microbial infection. Hence, this paper investigates the antimicrobial activities of 10 antihistaminics belonging to both old and new generations using multiresistant Gram-positive and Gram-negative clinical isolates. The bacteriostatic activity of antihistaminics was investigated by determining their MIC both by broth and agar dilution techniques against 29 bacterial strains. Azelastine, cyproheptadine, mequitazine and promethazine were the most active among the tested drugs. Diphenhydramine and cetirizine possessed weaker activity whereas doxylamine, fexofenadine and loratadine were inactive even at the highest tested concentration (1 mg/ml). The MIC of meclozine could not be determined as it precipitated with the used culture media. The MBC values of antihistaminics were almost identical to the corresponding MIC values. The bactericidal activity of antihistaminics was also studied by the viable count technique in sterile saline solution. Evident killing effects were exerted by mequitazine, meclozine, azelastine and cyproheptadine. Moreover, the dynamics of bactericidal activity of azelastine were studied by the viable count technique in nutrient broth. This activity was found to be concentration-dependant. This effect was reduced on increasing the inoculum size while it was increased on raising the pH. The post-antimicrobial effect of 100 µg/ml azelastine was also determined and reached up to 3.36 h.
RESUMO
Antihistaminics are widely used for various indications during microbial infection. Hence, this paper investigates the antimicrobial activities of 10 antihistaminics belonging to both old and new generations using multiresistant Gram-positive and Gram-negative clinical isolates. The bacteriostatic activity of antihistaminics was investigated by determining their MIC both by broth and agar dilution techniques against 29 bacterial strains. Azelastine, cyproheptadine, mequitazine and promethazine were the most active among the tested drugs. Diphenhydramine and cetirizine possessed weaker activity whereas doxylamine, fexofenadine and loratadine were inactive even at the highest tested concentration (1 mg/ml). The MIC of meclozine could not be determined as it precipitated with the used culture media. The MBC values of antihistaminics were almost identical to the corresponding MIC values. The bactericidal activity of antihistaminics was also studied by the viable count technique in sterile saline solution. Evident killing effects were exerted by mequitazine, meclozine, azelastine and cyproheptadine. Moreover, the dynamics of bactericidal activity of azelastine were studied by the viable count technique in nutrient broth. This activity was found to be concentration-dependant. This effect was reduced on increasing the inoculum size while it was increased on raising the pH. The post-antimicrobial effect of 100 fg/ml azelastine was also determined and reached up to 3.36 h.
RESUMO
Os objetivos do presente trabalho foram avaliar se o Super Bonder" apresenta algum risco de veiculação de microorganismos em humanos e se possui alguma atividade bactericida ou bacteriostática para cocos gram-positivo. Foi testada a esterilidade de dez tubas do adesivo nos meios de cultivo BHI, agar sangue, agar Sabouraud com cloranfenicol e Mycosel. A provável ação bactericida ou bacteriostática do adesivo Super Bonder"', in vitro, foi verificada utilizando cepas de Staphylococcus aureus e staphylococcus epidermidir, semeadas em meio de cultura agar sangue e agar Mueller-Hinton. Nao foi observado crescimento de microrganismos nos meios de cultura contendo somente gotas de Super Bonder"'. No agar sangue, observou-se ausência de beta-hemólise e de crescimento bacteriano nas áreas de sobreposição do adesivo. Em agarMueller-Hinton, houve rarefação de colônias ao redor das gotas do cianoacrilato.Os dados deste trabalho mostram que a cola de cianoacrilato Super Bonder"' parece ser livre de contaminação por microrganismos e apresenta possfvel atividade bacteriostatica in vitro.
The purposes of the present study were to verify the human's risk of the Super Bondet microorganisms' diffusion and the probably biocide or bacteriostatic adhesive's activity for gram-positive cocci. The sterility of ten tubes of the adhesive was tested in BHI culture tube and blood-agar, agar-Sabouraud with cloranfenicol and Mycosel culture plates. The biocide or bacteriostatic activity of the Super Bondet adhesive, in vitro, was verified using cultures of Staphylococcus aureus and staphylococcus epidermidis,seeded on blood-agar and agar-Mueller-Hinton culture plates. No microorganisms' growth was observed in the culture plates containing only drops of the Super Bondet. In agar-Mueller-Hinton, zones with reduced number of colonies were noticed around the cyanoacrylate's drops. In blood-agar, absence of haemolysis-beta and bacterial growth were observed in the covered areas of the adhesive. According to the results of this investigation, the Super Bondet cyanoacrylate is free of microorganisms' diffusion and probably inhibits in vitro the bacterial growth.
Assuntos
Atividade Bactericida do Sangue , Cloranfenicol , Poluição Ambiental , Cianoacrilatos , Staphylococcus aureus , Staphylococcus epidermidisRESUMO
El cloranfenicol es un antimicrobiano cuyo mecanismo de acción radica en la inhibición de la síntesis proteica bacteriana y posee un amplio espectro de acción. La dosificación en adultos y niños está dada no sólo por peso en kilos sino por la edad cronológica, en especial en estos últimos. Su uso actualmente está limitado a la salmonellosis tífica; pero tiene otras aplicaciones como en la meningitis por meningococo, en especial en los pacientes alérgicos a los betalactámicos. Sus reacciones adversas como la aplasia medular y el síndrome del niño gris, se presentan en 1 por 30.000 y l por 70.000 pacientes respectivamente; siendo causadas por idiosincrasia y por el uso de dosis superiores a los rangos terapéuticos.
Chloramphenicol is a bacterostatic agent it inhibits bacterial protein synthesis and it has a wide spectrum activity. The dosage in adults and children depends not only on weight but on chronological age. Its use is limited to salmonella typi but can also be used for Meningococcal Meningitis in patients who are allergic to beta lactamics. The adverse reaction are bone marrow depression and the Gray Baby Syndrome present in 1/ 30.000 and 1 / 70.000 respectively which have idiosyncratic cause and also from use of high doses.
Assuntos
Masculino , Adulto , Feminino , Criança , Antibacterianos , Infecções Bacterianas , Cloranfenicol , Inibidores da Síntese de Proteínas , Infecções por Bactérias Gram-Negativas , Infecções por Bactérias Gram-Positivas , Infecções por SpirochaetalesRESUMO
Background. Cranberry juice is used to prevent urinary infections but it is not known if it inhibits bacterial growth in urine or in bacteriologic broth. Objective. Determining if cranberry juice has bacteriostatic properties. Methods. The urine of 20 female university students was studied before and after drinking cranberry juice. Both specimens were submitted to pH determination and inoculated with a control strain of Escherichia coli. After 1 and 2 hours of incubation with the inoculum, the urine specimens were plated on agar to determine their bacterial counts. Additionally, the growth of 10 E. coli strains were studied in broths with serial dilutions of juice. Results. No inhibitory effect on bacterial growth was observed in urine after drinking cranberry juice. After 1 and two hours of incubation with the E. coli inoculum, control urine grew an average 132.2 and 153 x 10³ colony-forming units/mL, respectively. After 1 and two hours of incubation with the inoculum, post-intervention urine grew an average 141.4 and 170.6 x 10³ CFU/mL, respectively (p > 0.05). Against expectations, an increment was observed in urinary pH after drinking the juice (average pH in controls, 5.8 vs. 6.2 in post-intervention specimens; p = 0.043). In vitro analysis did not find a negative trend of E. coli growth in broths with higher concentrations of juice. Conclusions. Cranberry juice was not associated with bacteriostatic properties and its ingestión was not followed by a drop in urinary pH, which suggests that these are not its potential beneficial effects for the management and the prevention of urinary tract infections.
Antecedentes. El jugo de arándano se utiliza en la prevención de infecciones urinarias, pero se desconoce si tiene efecto inhibitorio de la multiplicación bacteriana en orina o en caldo de cultivo. Objetivo. Determinar si el jugo de arándano tiene efectos bacteriostáticos. Métodos. Se estudió en orina de 20 universitarias, antes y tres horas después de la ingestión de jugo de arándano; en ambos especímenes se determinó el pH y se inoculó una cepa de Escherichia coli. A una y dos horas de incubación con el inoculo, los especímenes se sembraron en agar para determinar sus cuentas bacterianas. Se estudió además el crecimiento de 10 cepas de E. coli en caldos con seis concentraciones diferentes de jugo de arándano. Resultados. No se observó un efecto bacteriostático en orina luego de la ingestión del jugo de arándano. Luego de una y dos horas de incubación con la cepa de E. coli, la orina control brindó una cuenta media de 132.2 y 153 x 10³ UFC/ inL, respectivamente. La cuenta similar de la orina postingestión del jugo brindó una media de 141.4 y 170.6x 10³ UFC/mL, respectivamente (p > 0.05). Contra lo esperado, se observó un incremento del pH urinario después de ingerir el jugo (media del pH en orina control: 5.8 vs. 6.2 en orina postingestión; p = 0.043). En el análisis in vitro no se encontró tendencia negativa del crecimiento de E. coli en caldo de cultivo con mayores concentraciones de jugo. Conclusiones. No se observó efecto bacteriostático o de acidificación urinaria del jugo de arándano, lo cual sugiere que no son éstos sus posibles efectos benéficos para el manejo y la prevención de las infecciones de vías urinarias.