Abstract I. paraguariensis St. Hil. is a south American species of agronomic interest with studies supporting its medicinal properties. As the investigation of active ingredients with antimicrobial effect from medicinal plants is a suitable approach to the current antibacterial resistance problem, the aim of the present study was to determine the antibacterial activity of yerba mate ethanolic extracts against carbapenemase-producing gram-negative bacteria (reference strains and clinical isolates). Extracts showed antibacterial activity against Klebsiella pneumoniae ATCC® BAA-2342™ (KPC producing), Providencia rettgeri (NDM producing), Pseudomonas aeruginosa (MBL producing) and P. aeruginosa (VIM producing) at the concentrations tested. The Minimal-Inhibitory-Concentration and Minimal-Bactericidal-Concentration values ranged between 1 and 32 mg.ml-1 for the reference strains, and between 0.125 and 1 mg.ml-1 for the clinical isolates. The MBC/MIC index characterized the extracts as bactericidal. The combinations of commercial antibiotics and extracts showed a synergistic action on the reference strains studied. The lethal concentration 50 obtained using the Artemia salina toxicity assay were higher than 1 mg.ml-1 for all the extracts, indicating a low toxicity. The in vitro activity and low toxicity suggest that ethanolic I. paraguariensis leaf extracts constitute an outstanding source for new antibacterial compounds, and further studies should be carried out to understand their mechanism of action. I St Hil properties problem carbapenemaseproducing carbapenemase producing gramnegative gram negative isolates . isolates) ATCC BAA2342™ BAA2342 BAA 2342™ 2342 BAA-2342 KPC producing, , NDM MBL P VIM tested MinimalInhibitoryConcentration Minimal Inhibitory Concentration MinimalBactericidalConcentration Bactericidal 3 mg.ml1 mgml1 mgml mg.ml mg ml mg.ml- 0125 0 125 0.12 MBCMIC MBC MIC bactericidal studied 5 compounds BAA234 234 BAA-234 ml1 012 12 0.1 BAA23 23 BAA-23 01 0. BAA2 2 BAA-2 BAA-

RESUMO A produção de mudas de erva-mate através de sementes tem várias limitações, que podem ser superadas por técnicas de propagação vegetativa ex vitro, como miniestacas, nas quais geralmente é necessário o uso de fertilizantes químicos sintéticos e fungicidas. Portanto, há uma tendência para a agricultura sustentável, usando biofertilizantes (bactérias promotoras de crescimento) e biocontroladores (Trichoderma sp.). Portanto, os objetivos deste trabalho foram avaliar o efeito dos biofertilizantes na produção de miniestacas a partir de minicepas de erva-mate; bem como o efeito dos biocontroladores na sobrevivência e na capacidade de enraizamento de miniestacas. Bacillus sp. e Trichoderma asperelloides de erva-mate foram utilizados sob duas condições de radiação. Houve uma relação positiva entre a disponibilidade de radiação e a produção de miniestacas e a capacidade de enraizamento. Todos os minicepas brotaram independentemente dos tratamentos. A maior produção de miniestacas viáveis ocorreu em uma situação de alta radiação e fertilização; enquanto os tratamentos com bactérias promotoras de crescimento e alta radiação apresentaram valores intermediários. As miniestacas inoculadas com Trichoderma asperelloides apresentaram maior porcentagem de enraizamento, maior número e longitude de raízes que as miniestacas tratadas com fungicida. Portanto, provamos que o uso de produtos químicos pode ser substituído por produtos biológicos e esse fato atingem alcança rendimentos aceitáveis.

ABSTRACT The production of yerba mate seedlings through seeds has several limitations, which can be overcome by ex vitro vegetative propagation techniques such as the mini-cuttings, in which it is usually necessary to use synthetic chemical fertilizers and fungicides. However, there is a tendency towards sustainable agriculture, using biofertilizers (growth-promoting bacteria) and biocontrollers (Trichoderma sp.). Therefore, the objectives of this work were to evaluate the effect of biofertilizers on the production of mini-cuttings from yerba mate mini-stumps; as well as the effect, of biocontrollers on survival and rooting capacity of mini-cuttings. Strains of Bacillus sp. and Trichoderma asperelloides of yerba mate were used under two radiation conditions. There was a positive relationship between the availability of radiation and the production of mini-cuttings and the rooting capacity. All the mini-stumps sprouted regardless of treatments. The largest production of viable mini-cuttings occurred in a situation of high radiation and fertilization; while the treatments with growth-promoting bacteria and high radiation had intermediate values. The mini-cuttings inoculated with Trichoderma asperelloides had higher rooting percentage, greater number and length of roots than the mini-cuttings treated with fungicide. Therefore, we demonstrated that the use of chemical products can be replaced by biological ones and achieves acceptable yields.