RESUMO
Multidrug resistance in the nosocomial pathogen Acinetobacter baumannii limits therapeutic options and impacts on clinical care. Resistance against carbapenems, a group of last-resort antimicrobials for treating multidrug-resistant (MDR) A. baumannii infections, is associated with the expression (and over-expression) of carbapenemases encoded by the blaOXA genes. The aim of this study was to determine the prevalence of antimicrobial-resistant A. baumannii associated with infection in three hospitals in southern Vietnam and to characterize the genetic determinants associated with resistance against carbapenems. We recovered a total of 160 A. baumannii isolates from clinical samples collected in three hospitals in southern Vietnam from 2012 to 2014. Antimicrobial resistance was common; 119/160 (74 %) of isolates were both MDR and extensively drug resistant (XDR). High-level imipenem resistance (>32 µg ml-1) was determined for 109/117 (91.6 %) of the XDR imipenem-nonsusceptible organisms, of which the majority (86.7 %) harboured the blaOXA-51 and blaOXA-23 genes associated with an ISAba1 element. Multiple-locus variable number tandem repeat analysis segregated the 160 A. baumannii into 107 different multiple-locus variable number tandem repeat analysis types, which described five major clusters. The biggest cluster was a clonal complex composed mainly of imipenem-resistant organisms that were isolated from all three of the study hospitals. Our study indicates a very high prevalence of MDR/XDR A. baumannii causing clinically significant infections in hospitals in southern Vietnam. These organisms commonly harboured the blaOXA-23 gene with ISAba1 and were carbapenem resistant; this resistance phenotype may explain their continued selection and ongoing transmission within the Vietnamese healthcare system.
Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Carbapenêmicos/farmacologia , Análise por Conglomerados , Infecção Hospitalar/microbiologia , DNA Bacteriano/genética , Feminino , Hospitais , Humanos , Imipenem/farmacologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Tipagem de Sequências Multilocus , Fenótipo , Prevalência , Sequências de Repetição em Tandem , Vietnã/epidemiologia , Adulto Jovem , beta-Lactamases/genética , beta-Lactamases/metabolismoRESUMO
BACKGROUND: Traditional formulae usually exhibit therapeutic effects through the combinations of different ingredients. The purpose of this study was to investigate in vitro anti-oxidative activity of Thanh Hao Miet Giap Thang (THMGT) (Sweet Wormwood and Tortoise Shell Decoction) formula and the interactions of its ingredients leading to the overall anti-oxidative effect. MATERIALS AND METHODS: We prepared 31 combinations containing two to four of the five ingredients including Herba Artemisia apiacea L (HbA), Carapax Trionycis (Tryonix sinensis) (CT), Rhizoma Anemarrhenae (Anemarrhena asphodeloides) (RzA), Radix Rehmanniae (Rehmannia glutinosa Libosch) (RdR), Moutan Cortex (Paeonia suffruticosa) (MC). These combinations were tested for anti-oxidative activity using DCFH-DA and DPPH assays on Hep G2 cells. We also analyzed changes in expression of genes involved in antioxidant defense system including Nuclear Factor Erythroid-Derived 2-Like 2 (NFE2L2), catalase (CAT), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), cytoplasmic superoxide dismutase (SOD1), mitochondrial superoxide dismutase (SOD2). RESULTS: The complete formula and all combinations containing Moutan Cortex showed high antioxidant activity in both radical solution-based chemical assay and cellular-based assay. On the contrary, Carapax Trionycis displayed inhibitory effect on the overall antioxidant activity when present in a combination, an effect clearly emphasized in cellular-based assay. Hep G2 cells treated with the formula showed increased gene expression of HO-1 and SOD2 while expression of CAT, SOD1, GPx was unchanged. CONCLUSION: Our results suggested that THMGT had anti-oxidative activity essentially through intrinsic reducing capacities and the overall activity of the formula resulted from enhancing and inhibiting interactions of ingredients.
Assuntos
Antioxidantes/farmacologia , Artemisia , Medicamentos de Ervas Chinesas/farmacologia , Heme Oxigenase-1/metabolismo , Paeonia , Superóxido Dismutase/metabolismo , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Expressão Gênica , Glutationa Peroxidase/metabolismo , Células Hep G2 , Humanos , Técnicas In Vitro , TartarugasRESUMO
Garcinia vilersiana is a traditional medicinal plant in Vietnam. The petroleum ether extract of stem bark of Garcinia vilersiana (GVE) was prepared to evaluate its potential to activate Nrf2, a transcription factor of antioxidant and detoxifying enzymes. Exposure of mouse macrophage RAW264.7 cells to GVE (0.625-2.5 µg/ml) resulted in a significant activation of Nrf2, as evaluated by nuclear accumulation of this transcription factor, and increased antioxidant response element (ARE) binding activity in a time- and concentration-dependent manner. As a result, GVE caused ARE-dependent up-regulation of heme oxygenase-1 (HO-1) in the cells. These results suggest that GVE contains components that have the ability to activate the Nrf2/ARE/HO-1 signaling pathway, leading to cellular protection.
