Department of Biotechnology, Central University of South Bihar, Panchanpur, Gaya, Bihar, 824236, India.
National Institute of Plant Genome Research (NIPGR), New Delhi, India.
BMC Complement Altern Med. 2019 Jun 6;19(1):119. doi: 10.1186/s12906-019-2532-6.
Staphylococcus aureus is a notorious pathogen which often causes nosocomial and community attained infections. These infections steadily increased after evolving the resistance due to indecorous practice of antibiotics and now become a serious health issue. Ouabain is a Na/K-ATPase inhibitor that leads to increase the heart contraction in patients with congestive heart failure.
In the present study, in vitro antimicrobial effect of ouabain together with aminoglycosides was determined against clinical and non-clinical S. aureus strains. Using checkerboard, Gentamycin uptake and biofilm assays, we analysed he interactions of ouabain with aminoglycosides.
Ouabain induced the staphylocidal potency of aminoglycosides by remarkably reducing the MIC of gentamycin (GEN) by 16 (0.25 μg/mL), 8 folds (0.5 μg/mL) amikacin (AMK); and 16 folds (1.0 μg/mL) with kanamycin (KAN), compared to their individual doses. OBN severely reduced cell viability within 60 min with GEN (1 μg/mL), KAN (2 μg/mL) and 90 min with AMK (1 μg/mL). This bactericidal effect was enhanced due to GEN uptake potentiated by 66% which led to increase the cell permeability as revealed by leakage of bacterial ATP and nitrocefin assay. The biofilm adherence disrupted by 80 and 50% at 5 mg/mL and 1.5 mg/mL OBN and 50 and 90% biofilm formation was inhibited at 5 mg/mL (MBIC) and 10 mg/mL (MBIC), respectively. Moreover, OBN with GEN further induced biofilm inhibition by 67 ± 5% at pH 7.0.
Taken together, we established that OBN synergizes the antimicrobial activity of aminoglycosides that induces cell killing due to intracellular accumulation of GEN by disturbing cell homeostasis. It may be proven an effective approach for the treatment of staphylococcal infections.
金黄色葡萄球菌是一种臭名昭著的病原体，它经常导致医院获得性和社区获得性感染。由于抗生素使用不当，这些感染不断增加，现在已成为一个严重的健康问题。哇巴因是一种 Na/K-ATP 酶抑制剂，可导致充血性心力衰竭患者的心脏收缩增加。
在本研究中，我们测定了哇巴因与氨基糖苷类药物联合应用对临床和非临床金黄色葡萄球菌菌株的体外抗菌作用。我们使用棋盘法、庆大霉素摄取和生物膜测定法分析了哇巴因与氨基糖苷类药物的相互作用。
哇巴因显著降低庆大霉素（GEN）、阿米卡星（AMK）和卡那霉素（KAN）的 MIC 值，使氨基糖苷类药物的杀菌能力增强 16 倍（0.25μg/mL）、8 倍（0.5μg/mL）和 16 倍（1.0μg/mL）。与单独用药相比，OBN 在 60min 内可使 GEN（1μg/mL）、KAN（2μg/mL）和 90min 内使 AMK（1μg/mL）的细胞活力显著降低。这种杀菌作用增强是由于 GEN 摄取增加了 66%，导致细胞通透性增加，这可以通过细菌 ATP 泄漏和硝基头孢菌素测定法显示。在 5mg/mL 和 1.5mg/mL 的 OBN 作用下，生物膜黏附分别被破坏了 80%和 50%，在 5mg/mL（MBIC）和 10mg/mL（MBIC）时，生物膜形成分别被抑制了 50%和 90%。此外，OBN 与 GEN 在 pH 值为 7.0 时进一步诱导生物膜抑制率增加了 67%±5%。
综上所述，我们发现 OBN 与氨基糖苷类药物具有协同作用，通过扰乱细胞内稳态使 GEN 积累，从而诱导细胞死亡，增强了氨基糖苷类药物的抗菌活性。它可能被证明是治疗葡萄球菌感染的一种有效方法。
