Compounds capable of inhibiting the efflux pump mechanism are a promising alternative against bacterial resistance because, when combined with antibiotics, they can increase the effectiveness of these drugs by inhibiting active efflux. Elaiophylin, derived from Streptomyces hygroscopicus, is a natural antibiotic that exhibits a variety of biological activities, including antibacterial activity. However, its potential as an inhibitor of the bacterial efflux mechanism has not been investigated. This study evaluated the ability of Elaiophylin to inhibit the NorA efflux pump in Staphylococcus aureus strains. Therefore, tests were performed to obtain the Minimum Inhibitory Concentration (MIC) and to verify the ability of Elaiophylin to potentiate the MIC of the antibiotic Norfloxacin and Ethidium Bromide (EtBr), known substrates of NorA efflux. Real-time PCR and molecular docking assays were also performed to assess the potential of Elaiophylin against NorA. The strains SA-1199 (wild type) and SA-1199B (NorA over-expressed) of S. aureus were used for this study. The results showed that Elaiophylin significantly decreased the MIC of Norfloxacin and EtBr, increasing the activity of these substrates against S. aureus, which carries the efflux protein NorA. However, Elaiophylin provided a non-significant reduction in norA gene expression, however, molecular docking demonstrated a high binding affinity between Elaiophylin and NorA efflux protein, indicating that Elaiophylin can act as a potential NorA in S. aureus.

能够抑制外排泵机制的化合物是对抗细菌耐药性的有希望的替代品，因为当与抗生素结合使用时，它们可以通过抑制主动外排来提高这些药物的有效性。Elaiophylin 来源于吸水链霉菌，是一种天然抗生素，具有多种生物活性，包括抗菌活性。然而，尚未研究其作为细菌外排机制抑制剂的潜力。本研究评估了油茶素抑制金黄色葡萄球菌中NorA 外排泵的能力菌株。因此，进行了测试以获得最小抑制浓度 (MIC) 并验证油茶素增强抗生素诺氟沙星和溴化乙锭 (EtBr) 的 MIC 的能力，它们是 NorA 流出的已知底物。还进行了实时 PCR 和分子对接测定以评估油茶素对抗 NorA 的潜力。本研究使用金黄色葡萄球菌的菌株 SA-1199（野生型）和 SA-1199B（过表达 NorA）。结果表明，Elaiophylin 显着降低了诺氟沙星和 EtBr 的 MIC，增加了这些底物对携带外排蛋白 NorA 的金黄色葡萄球菌的活性。然而，Elaiophylin 没有显着降低norA基因表达，然而，分子对接显示油茶素和 NorA 流出蛋白之间的高结合亲和力，表明油茶素可以作为金黄色葡萄球菌中的潜在 NorA 。