Spread of Multi-Drug Resistant (MDR) bacteria prompted the surge in need for new antimicrobial agents, especially those found in nature. Ilex paraguariensis commonly known as Yerba Mate, a plant native to South America, is known for its many pharmacological properties. In this study, the aqueous extracts of Yerba Mate were tested for antibacterial activity against different bacterial species. A promising activity was shown against Staphylococcus aureus (standard and clinical strains), Klebsiella pneumoniae (standard strains) and Acinetobacter baumanii (standard and clinical strains) with Minimum Inhibitory Concentrations (MICs) of 1.88–3.75 mg/mL, 1.88 mg/mL and 2.5–10 mg/mL respectively. Metabolites produced after in-vitro digestion of Yerba Mate extracts gave similar antibacterial activity against S. aureus. Combination assays between Yerba Mate extracts and different classes of antibiotics suggest an additive effect with the antibiotic Clarithromycin and an antagonistic effect with Gentamicin when tested on S. aureus strains of different profiles of resistance. Furthermore, Yerba Mate was able to delay coagulase activity of S. aureus strains when incubated with the extract at ½ MIC concentration. Further work should be done in order to isolate the compound(s) responsible for Yerba Mate's antibacterial activity and to understand its mechanism of action.

耐多药（MDR）细菌的扩散促使对新型抗菌剂的需求激增，尤其是自然界中发现的抗菌剂。巴拉圭冬青树（Ilex paraguariensis）通常被称为Yerba Mate，它是南美本地植物，因其许多药理特性而闻名。在这项研究中，Yerba Mate的水提物被测试了对不同细菌种类的抗菌活性。对金黄色葡萄球菌（标准菌株和临床菌株），肺炎克雷伯菌（标准菌株）和鲍曼不动杆菌（标准菌株和临床菌株）显示出极有希望的活性，其最低抑菌浓度（MIC）为1.88–3.75 mg / mL，1.88 mg / mL和分别为2.5–10 mg / mL。代谢产物产生后Yerba Mate提取物的体外消化对金黄色葡萄球菌具有相似的抗菌活性。在不同抗性的金黄色葡萄球菌菌株上进行测试时，Yerba Mate提取物与不同种类的抗生素之间的联合测定结果表明，与抗生素克拉霉素具有叠加作用，与庆大霉素具有拮抗作用。此外，当与提取物在½MIC浓度下孵育时，Yerba Mate能够延迟金黄色葡萄球菌菌株的凝固酶活性。为了分离出负责Yerba Mate抗菌活性的化合物并了解其作用机理，应该做进一步的工作。