RESUMO
AIMS: This study investigates the antimicrobial activity in Staphylococcus aureus isolates (methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA)) and antioxidant activity of green propolis, Baccharis dracunculifolia DC extracts and Artepillin C™. METHODS AND RESULTS: The amount of Artepillin C in different extracts was determined by high performance liquid chromatography analysis. Minimum inhibitory concentration 90 (MIC90) was determined using 40 isolates of S. aureus inoculated in Müeller-Hinton agar culture medium containing the green propolis and B. dracunculifolia DC extracts. PVEE (green propolis ethanolic extract) and BDEH (B. dracunculifolia hexanic extract) showed the greatest antimicrobial activity with MIC90 values of 246·3 and 295·5 µg ml-1 respectively. Green propolis ethanolic and hexanic extracts (PVEE and PVEH respectively) showed the greatest antioxidant activity assessed by DPPH (1,1-diphenyl-2-picryl hydrazyl radical) with IC50 values of 13·09 and 95·86 µg ml-1 respectively. CONCLUSIONS: Green propolis ethanolic displays better antimicrobial and antioxidant activities compared to other extracts. These activities may be related to the presence of Artepillin C in synergism with the other constituents of the extracts. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, the antimicrobial activity of the extracts of green propolis and B. dracunculifolia DC demonstrated in MRSA and MSSA clinical isolates indicated that they can be important tools to treat infections caused by these bacteria.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Baccharis/química , Fenóis/farmacologia , Fenilpropionatos/farmacologia , Própole/farmacologia , Antibacterianos/análise , Antioxidantes/análise , Fenilpropionatos/análise , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Própole/química , Staphylococcus aureus/efeitos dos fármacosRESUMO
We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100% sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92%, respectively, and 98% specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98%, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.
Assuntos
Antibacterianos/farmacologia , Cefoxitina/farmacologia , Resistência a Meticilina , Oxacilina/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Proteínas de Bactérias/análise , Criança , Difusão , Humanos , Testes de Sensibilidade Microbiana/métodos , Proteínas de Ligação às Penicilinas , Reprodutibilidade dos Testes , Staphylococcus aureus/isolamento & purificaçãoAssuntos
Antibacterianos/farmacologia , Bacteriemia/epidemiologia , Carbapenêmicos/farmacologia , Estado Terminal , Infecções por Bactérias Gram-Negativas/epidemiologia , Resistência beta-Lactâmica , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Criança , Pré-Escolar , Feminino , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/mortalidade , Hospitais de Ensino , Humanos , Lactente , Masculino , Fatores de Risco , América do Sul/epidemiologia , Análise de Sobrevida , Centros de Atenção Terciária , Resultado do TratamentoRESUMO
We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100 percent sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92 percent, respectively, and 98 percent specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98 percent, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.