An increasing incidence of nosocomial infections caused by non-multiresistant methicillin-resistant Staphylococcus aureus (nMMRSA) has been reported worldwide. The present study genotyped nMMRSA isolates obtained from hospitals in two cities in Brazil. The hospital isolates displayed pulsed-field gel electrophoresis (PFGE) patterns that were similar to those of the USA100 (ST5-SCCmecII) and USA 800 (ST5-SCCmecIV) strains, which are related to the New York/Japan and paediatric clones, respectively. Carriage of SCCmecIV and the classification by multilocus sequence typing (MLST) of a representative of this PFGE pattern in clonal complex 5 (CC5) confirmed the genetic relationship of the Brazilian isolates with USA800. The USA800-related Brazilian isolates were responsible for severe nosocomial infections in compromised adults and elderly patients in Brazil. A higher growth rate, an ability to form biofilm on inert polystyrene surfaces and the presence of the egc locus may have contributed, at least in part, to the fitness of these organisms as global nosocomial pathogens.
Antimicrobial activities of "babaçu" (Orbignya martiana), "cardo santo" (Argemone mexicana), "mentrasto" (Ageratum conyzoides), "cavalinha" (Equisetum yeamalis) and "terramicina" (Alternanthera brasiliana), used by Brazilian population as antiinflamatory medicine, were studied on Staphylococcus aureus. The freezer dried hydroalcoholic extracts solutions were tested for 7 strains of Staphylococcus aureus, which two of those are methicillin resistant (MRSA). The diffusion method on agar-agar, using holes technique, with tetracycline chlorydrate as standard. "Babaçu", "cardo santo" and "terramicina" showed antimicrobial activity, within of those "terramicina" inhibited 6 strains, presenting zone inhibition of 22 mm compared to standard antibiotic (34 mm), except the seventh strain which was also tetracycline resistant.A WHO considerou que no mundo aproximadamente 80% de uma população de 4 bilhões dependem principalmente da medicina tradicional para seus cuidados primários de saúde, bem a partir, do uso de extratos de plantas ou de seus princípios ativos 1,2,7 . Assim serão determinadas a atividade antimicrobiana das plantas babaçu (Orbignya martiana), cardo santo (Argemone mexicana), mentrasto (Ageratum conyzoides), cavalinha (Equisetum yeamalis) e terramicina (Alternanthera brasiliana) frente as cepas de Staphylococcus aureus. Material e MétodosAs cepas de Staphylococcus aureus usadas no teste são apresentadas na tabela 1. No estudo são retidas duas cepas padrões (ATCC) de reconhecida resistência, utilizadas nos testes para conservantes e desinfetantes, cinco isolados hospitalares: três meticilina sensível e dois meticilina resistente.As plantas com seus extratos são apresentados na tabela 2, todos os testes foram realizados com extratos aquosos obtidos a partir de liofilizados de extratos hidroalcóolicos (1:1) das referidas plantas.No caso da Alternanthera brasiliana (terramicina) o extrato tinha uma consistência mais pastosa, que dificultou a pesada.A metodologia empregada foi a técnica de discos por difusão em ágar e a técnica de poços por difusão em ágar, utilizando-se como antibiótico padrão: cloridrato de tetraciclina (solução mãe 1 mg/ml) e como meio ágar Müeller Hinton semeado na superfície com os inóculos bacterianos. O uso de dois ou mais métodos para o estudo da atividade antimicrobiana permite obter melhores resultados 9 . As placas foram deixadas em repouso por 40 min à temperatura ambiente antes de incubar (tempo de predifusão).
RESUMO:No presente estudo objetivou-se avaliar a atividade antimicrobiana e sinérgica de 4 frações das folhas de Schinopsis brasiliensis Engl (F1', F2', F1" e F2") frente às cepas Staphylococcus aureus MRSA multirresistentes. Os métodos utilizados foram poços de difusão em ágar, concentração mínima inibitória (CMI) -diluição em ágar, e bioautografia. Nos resultados bioautográficos observou-se três halos de inibição relacionados, no mínimo, à quatro constituintes ativos; sendo dois deles isolados das folhas (galato de metila e ácido gálico). A F2" (200µg/mL) apresentou halos de inibição de 16 e 19mm frente as cepas de S. aureus multirresistente e Klebsiella pneumoniae, e CMI 100µg/mL, respectivamente. Quanto as análises das associações das frações F1" ou F2" (25 e 50µg/mL) com a tetraciclina e oxacilina, mostraram ações aditiva e sinérgica para a F2" (50µg/mL), embora não suficiente para que a CMI atingisse valores inferiores a 2 e 4µg/mL, necessário para serem classificadas como cepas sensíveis a oxacilina e tetraciclina, respectivamente. "Assim, conclui-se que a F2" das folhas de S. brasiliensis apresentou potencial antimicrobiano frente às cepas de S. aureus MRSA multirresistentes e que as associações das frações com os antibióticos testados não apresentaram benefícios não justificando o uso concomitante. Palavras-chave: Schinopsis brasiliensis, Staphylococcus aureus, Atividade antimicrobiana, Multidroga-Resistente.ABSTRACT: Antimicrobial and synergic activity of fractions from the leaves of Schinopsis brasiliensis Engl. against Staphylococcus aureus multiresistant clones. The aim of this study was to evaluate the antimicrobial and synergic activity of 4 leaf fractions of Schinopsis brasiliensis Engl (F1', F2', F1" and F2") against multidrug-resistant Staphylococcus aureus strains. The used methods were agar well diffusion, minimum inhibitory concentration (MIC) -agar dilution, and bioautography. The bioautographic results showed three inhibition zones that corresponded to at least four active compounds, two of which (methyl gallate and gallic acid) have already been isolated from leaves. The F2" (200µg/mL) fraction showed inhibition zones of 16 mm and 19 mm against S. aureus multidrug-resistant and Klebsiella pneumoniae strains and a MIC value of 100µg/mL, respectively. The analyses of associations of fraction F1" or F2" (25 and 50µg/mL) with tetracycline and oxacillin showed additive and synergistic action for F2" (50µg/mL), although it was not enough to decrease the MIC values to less than 2 and 4µg/ mL, necessary to classify the strains as susceptible to oxacillin and tetracycline, respectively. Thus, it was concluded that F2" from the leaves of S. brasiliensis showed antimicrobial potential against multidrug-resistant MRSA strains, and the associations of the fractions with the tested antibiotics showed no benefits, not justifying their concomitant use.
The N-alkylated derivatives from nitrofurazone were synthesised and evaluated in vitro for their efficacy as antimicrobial agents against representative strains, including methicillin-resistant Staphylococcus aureus (MRSA). The derivative 2a demonstrated greater activity than the prototype and was comparable to currently used antimicrobial drugs.
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