Atividade antibacteriana de nanopartículas de polipirrol diante de Staphylococcus aureus isolados de amostras de leite de vacas e cabras com mastite / Antibacterial behavior of polypyrrole nanoparticles against Staphylococcus aureus isolated from cows and goats with mastitis

The aim of the present study was to evaluate the antibacterial behavior of polypyrrole nanoparticles (PPy-NPs) in water against biofilm producer or not S. aureus isolated from cows and goats with mastitis. One hundred and thirty-eight isolates of S. aureus were initially evaluated for biofilm formation by spectrophotometry in microplates. In addition, the minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) of PPy-NPs in water for planktonic S. aureus were determined. From the bovine samples analyzed, 5 (4.46%) S. aureus isolates showed a strong biofilm production, 17 (15.18%) moderate production, 36 (32.14%) with weak production and 54 (48.21%) did not produce biofilms. Strains from goats (26) showed no biofilm production in 18 (69.23%) strains and weak biofilm production in 8 (30.76%) strains. The MIC and MBC of S. aureus to PPy-NPs were found in the same concentration (125搭/mL) in all strains tested, regardless of biofilm production or not. This finding provides a new insight into the interaction between PPy-NPs and S. aureus, and will offer potential benefits for the control of mastitis.(AU)

Atividade antimicrobiana in vitro de extratos de plantas do bioma caatinga em isolados de Escherichia coli de suínos / Antimicrobial activity in vitro extracts from caatinga plants in isolated Escherichia coli from pigs

RESUMO A suinocultura é uma atividade pecuária bem consolidada no Brasil. Por outro lado a colibacilose neonatal, cujo patógeno é Escherichia coli, pode diminuir a produtividade nas granjas e causar prejuízos aos produtores. O tratamento baseia-se na utilização de drogas antimicrobianas. Todavia, o uso indiscriminado dessas substâncias tem levado a seleção de cepas resistentes. Diante disso, a busca por alternativas terapêuticas, como as plantas medicinais, tem se tornado cada vez mais comum. Dessa maneira, objetivou-se determinar a atividade antimicrobiana de cinco extratos etanólicos de plantas do bioma caatinga: Amburana cearensis (Fr. Allem) A.C. Smith, Encholirium spectabile Mart., Hymenaea courbaril L, Neoglaziovia variegata Mez e Selaginella convoluta Spring frente a 43 isolados de Eschericha coli coletados de suínos. Para o teste de sensibilidade in vitro foi realizada a técnica da Concentração Bactericida Mínima (CBM) pelo método da microdiluição em microplaca. Os extratos apresentaram atividade antimicrobiana nas seguintes médias 138,75 175,28, 128,36, 127,71 e 129,33 μg/mL, respectivamente. Essa atividade antibacteriana pode estar relacionada a ação de metabólitos secundários presentes nos extratos dessas plantas. Dessa forma, nosso estudo pode contribuir para o desenvolvimento de alternativas terapêuticas no tratamento de infecções, como a colibacilose neonatal em suíno, bem como para o conhecimento acerca das plantas medicinais da Caatinga.

ABSTRACT Swine production is a well-established livestock activity in Brazil. On the other hand, the Neonatal Colibacillosis, whose pathogen is Escherichiacoli, can decrease the productivity on farms and cause losses to producers. The treatment of the disease is based on the use of antimicrobial drugs. However, the free use of these substances has led to the selection of resistant strains. Thus, the search for alternative therapies such as medicinal plants has become becoming increasingly common. In this context, we aimed to determine the antimicrobial activity of ethanol extracts of five plants from the caatinga biome: A. cearensis (Fr. Allem) AC Smith, Encholirium spectabile Mart, Hymenaea courbaril L, Neoglaziovia variegata Mez and Selaginella convoluta Spring in face of isolates of Eschericha coli collected from pigs. For the in vitro susceptibility testing, the method of Minimum Bactericidal Concentration (MBC) was chosen The extracts showed antimicrobial activity in the following averages 138.75 175.28, 128.36, 127.71 and 129.33 mg / mL, respectively. This antibacterial activity could be related to the action of secondary metabolites in the extracts of these plants. Thus, the current study can contribute to the development of alternative therapies for the treatment of infections such as swine Colibacillosis Neonatal, as well as to the knowledge of Caatinga medicinal plants.