Potencial antimicrobiano e caracterização fitoquímica de extratos da casca do caule de Drimys brasiliensis Miers (Winteraceae) / Antimicrobial potential and phytochemical investigation of stem bark extracts from Drimys brasiliensis Miers (Winteraceae)

Introdução: na área da saúde, a resistência aos antimicrobianos tem se constituído um grave problema, fazendo com que a busca por alternativas farmacológicas assuma grande importância. Produtos de origem natural, como extratos de plantas, têm sido pesquisados para uso potencial no tratamento antibacteriano. Drimys brasiliensis Miers (Winteraceae) é uma árvore nativa do Brasil que tem sido utilizada como medicinal. Objetivo: investigar o perfil fitoquímico e a atividade antimicrobiana de amostras obtidas a partir de extratos da casca do caule de Drimys brasiliensis. Metodologia: frações de características químicas variadas foram obtidas a partir de extratos da casca do caule da planta. Realizou-se o screening fitoquímico destas frações através de reações gerais de caracterização e cromatografia em camada delgada. As amostras foram testadas por difusão em ágar e por microdiluição contra bactérias Grampositivas e Gram-negativas e contra uma levedura. Resultados: o perfil fitoquímico mostrou diferenças entre as frações analisadas. Alcaloides foram detectados nas frações mais apolares. Taninos e flavonoides estavam presentes nas amostras mais polares e obtidas sem o uso de calor. As amostras com maior atividade antimicrobiana foram as obtidas com os solventes hexano e diclorometano, de características mais apolares. Destaca-se a atividade contra Bacillus cereus, Staphylococcus epidermidis, Staphylococcus aureus resistente à meticilina e Candida albicans. Conclusão: extratos da casca do caule de Drimys brasiliensis apresentam potencial ntimicrobiano, com destaque para as frações mais apolares contra bactérias gram positivas.

Introduction: in the health field, antimicrobial resistance has been a serious issue, making the search for pharmacological alternatives very important. Natural products, such as plant extracts, have been researched for potential use in antibacterial treatment. Drimys brasiliensis Miers (Winteraceae) is a tree native to Brazil that has been medicinally used. Objective: to investigate the phytochemical profile and antimicrobial activity of samples obtained from Drimys brasiliensis stem bark extracts. Methodology: fractions of different chemical characteristics were obtained from extracts of the stem bark. Phytochemical screening of these fractions was performed by general reactions and thin layer chromatography. Samples were tested by agar diffusion and microdilution against Gram-positive and Gram-negative bacteria and yeast. Results: the phytochemical profile showed differences between the analyzed fractions. Alkaloids were detected in the most nonpolar fractions. Tannins and flavonoids were present in the most polar samples and obtained without the use of heat. The samples with the highest antimicrobial activity were those obtained with hexane and dichloromethane solvents, which present the most nonpolar characteristics. We highlight the activity against Bacillus cereus, Staphylococcus epidermidis, Methicillin resistant Staphylococcus aureus and Candida albicans. Conclusion: Drimys brasiliensis stem bark extracts have antimicrobial potential, especially the most nonpolar fractions against gram positive bacteria.

Prevalence and antimicrobial susceptibility of non-fermenting Gram-negative bacilli isolated from clinical samples at a tertiary care hospital

Abstract INTRODUCTION: We compared the prevalence and antimicrobial susceptibility of non-fermenting gram-negative bacilli (NFGNB) isolated from clinical samples at a Brazilian tertiary care hospital in 2008 and 2013. METHODS: Collected data included patient's name, age, sex, inpatient unit, laboratory record number, type of biological material, culture test result, and antimicrobial susceptibility of isolated strains. RESULTS: Out of 19,112 culture tests analyzed, 926 (4.8%) were positive for NFGNB. Among these, 45.2% were metallo-beta-lactamase (MBL) producing strains. CONCLUSION: Between 2008 and 2013, the number of MBL-producing NFGNB isolates increased by 21.5%, which was accompanied by a consequent reduction in susceptibility to antimicrobials.

Occurrence and sensitivity profile of extended spectrum beta-lactamase-producing Enterobacteriaceae at a tertiary hospital in Southern Brazil

Abstract: INTRODUCTION: Nosocomial infections are closely associated with antimicrobial drug resistance. One of the most important mechanisms of resistance to β-lactam antibiotics is the production of extended spectrum β-lactamases (ESBLs). The objective of the present study was to evaluate the prevalence and antimicrobial susceptibility profile of ESBL-producing strains and to assess the evolution of antimicrobial drug resistance between 2007 and 2013 at the Hospital São Vicente de Paulo, Passo Fundo, State of Rio Grande do Sul, Brazil. METHODS: We conducted a descriptive, observational, cross-sectional study. Bacterial culture was performed from January to December 2013. The antimicrobial susceptibility profile of these cultures was determined using the disk diffusion method. Phenotypic screening for ESBL production was performed using the disk approximation method. RESULTS : We analyzed a total of 19,112 cultures, 11.5% of which were positive for Enterobacteriaceae. Of these, 30.3% of the isolates were positive for ESBL production, and the most prevalent species was Klebsiella sp. (37.5%). Over 95% of these isolates showed reduced susceptibility to all cephalosporins, aztreonam, and amoxicillin/clavulanic acid. The isolates also showed high sensitivity to the following antimicrobials: amikacin, meropenem, and piperacillin/tazobactam. Overall, the resistance rates among ESBL-producing Enterobacteriaceae decreased from 2007 to 2013. CONCLUSIONS : In our hospital, the increased sensitivity to certain antimicrobial agents seems to be directly related to the implementation of improvements in the methods to prevent and control nosocomial infections in addition to the natural development of other resistance mechanisms.

Proteinase activity in latex of three plants of the family Euphorbiaceae

In the family of Euphorbiaceae, the genera Euphorbia and Sapium are known to contain essentially latex-bearing species. In the present study, the latex of Euphorbia selloi (Klotzsch & Garcke) Boiss., Euphorbia papillosa A.St.-Hil., and Sapium glandulosum (L.) Morong, plants native from Brazil, were examined concerning proteolytic activity. All studied species have proteins with significant proteolytic activity and E. papillosa has the greatest specific activity. Aiming to verify the type of protease present, an assay with different inhibitors was performed. In the three tested plants, the proteolytic activity was significantly inhibited by a serine protease inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride (AEBSF). Using techniques of electrophoresis with polyacrylamide gels (SDS-PAGE), the subunits of proteins were separated according to their molecular masses, and the protein activity was visually detected by zymography.

Dentro da família Euphorbiaceae, os gêneros Euphorbia e Sapium são conhecidos por incluírem basicamente espécies produtoras de látex. No presente estudo, o látex das plantas Euphorbia selloi (Klotzsch & Garcke) Boiss., Euphorbia papillosa A.St.-Hil. e Sapium glandulosum (L.) Morong, espécies nativas do Brasil, foi analisado em relação à atividade proteolítica. Todas as amostras analisadas possuem proteínas com significativa atividade, sendo que o látex da espécie E. papillosa apresenta a maior atividade específica. Com o objetivo de analisar quais os tipos de proteases responsáveis pela atividade proteolítica, realizaram-se ensaios com diferentes inibidores. Nas três plantas testadas a atividade foi inibida significativamente pelo cloridrato de 4-(fluoreto de 2-aminoetilbenzenossulfonil) (AEBSF), um inibidor de serino-proteases. Utilizando técnicas de eletroforese em gel de poliacrilamida (SDS-PAGE), as subunidades das proteínas foram separadas de acordo com sua massa molecular e, através da zimografia, a atividade proteolítica pode ser detectada visualmente.

Efeito dos extratos aquosos de Baccharis ochracea Spreng. e Iodina rhombifolia Hook. et Arn. sobre a reproduçäo de ratas / Effect of aqueous extracts of Baccharis ochracea Spreng. and Iodina rhombifolia Hook. et Arn. over the reproduction of female rats

Baccharis ochracea Spreng. e Iodina rhombifolia Hook. et Arn., plantas nativas do Rio Grande do Sul e de utilizaçäo na medicina popular, foram testadas quanto ao efeito de seus extratos aquosos sobre a reproduçäo de ratas. Foram constituídos grupos experimentais com ratas grávidas que receberam diariamente, via intraperitonial, extratos aquosos das duas plantas na dose de 250 mg.kg-û, e um grupo-controle que recebeu água destilada na dose diária de 1 ml.kg-û. No grupo tratado com extrado de Baccharis ochracea, foi observada uma reduçäo significativa no desenvolvimento ponderal das ratas gestantes, no número de filhotes nascidos vivos, no desenvolvimento ponderal dos filhotes, do 1§ ao 21§ dia, e um aumento significativo no número de reabsorçöes. No grupo tratado com extrato de Iodina rhomvifolia, somente foi observada reduçäo significativa no desenvolvimento ponderal das ratas gestantes e aumento significativo no número de reabsorçöes