Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a major global health problem, and novel and effective antimicrobial drugs are urgently required to combat this life-threatening pathogen. Prodigiosin (PG) is a bacterial secondary metabolite with excellent anticancer and antibacterial properties. However, little is known about the antibacterial function of PG against MRSA. Therefore, the antibacterial efficacy of PG alone and PG in combination with different metal ions against clinic isolates of MRSA and methicillin-sensitive S. aureus (MSSA) strain was evaluated in the present study. The minimum inhibitory concentration of PG against both MRSA and MSSA was 0.25 μg/mL. However, 0.1 μg/mL PG showed a stronger inhibitory effect on MSSA cell growth (47.12%) than on MRSA cell growth (35.87%). Surprisingly, we observed a significant difference (p < 0.01) in membrane integrity between PG-treated MRSA and MSSA using the propidium iodide staining assay. Further, we found that in combination with PG, Zn²⁺, Al³⁺, and Cu²⁺ showed synergistic antibacterial effects against MRSA and MSSA. Our results could increase the current knowledge regarding the efficacy of PG in inhibiting the growth of different types of S. aureus clinical isolates and also offer a novel strategy for developing efficient antibacterial agents.

摘要

耐甲氧西林金黄色葡萄球菌(MRSA) 感染是一个主要的全球健康问题，迫切需要新型有效的抗菌药物来对抗这种威胁生命的病原体。灵菌红素 (PG) 是一种细菌次级代谢产物，具有优异的抗癌和抗菌特性。然而，关于 PG 对 MRSA 的抗菌功能知之甚少。因此，PG单独和PG与不同金属离子联合对临床分离株MRSA和甲氧西林敏感金黄色葡萄球菌的抗菌作用(MSSA) 菌株在本研究中进行了评估。PG对MRSA和MSSA的最小抑制浓度为0.25 μg/mL。然而，0.1 μg/mL PG 对 MSSA 细胞生长的抑制作用（47.12%）比对 MRSA 细胞生长的抑制作用（35.87%）更强。 令人惊讶的是，我们使用碘化丙啶染色试验观察到 PG 处理的 MRSA 和 MSSA 之间的膜完整性存在显着差异 ( p < 0.01)。此外，我们发现与PG结合，Zn ²⁺、Al ³⁺和Cu ²⁺显示出对MRSA和MSSA的协同抗菌作用。我们的结果可以增加目前关于 PG 抑制不同类型金黄色葡萄球菌生长功效的知识临床分离物，也为开发有效的抗菌剂提供了一种新的策略。