Food Science and Bioengineering School, Shaanxi University of Science and Technology, 710021, Xi'an, PR China.
Ningbo Municipal Center for Disease Control and Prevention, 315010, Ningbo, PR China.
J Antibiot (Tokyo). 2020 Jun;73(6):382-391. doi: 10.1038/s41429-020-0285-6. Epub 2020 Feb 12.
Previous studies demonstrated that ursolic acid (UA) present in apple pomace displays antimicrobial activity against some microorganisms, but the underlying mechanisms associated with this activity remain unexplored. Furthermore, there are no reports on the effect of UA on carbapenem-resistant Klebsiella pneumoniae (CRKP). This study examined the antimicrobial activity and mode of action of UA against CRKP was examined. Minimum inhibitory concentration (MIC) of UA against CRKP was determined by the agar dilution method. Variations in the intracellular pH (pHin), ATP concentration, and cell membrane potential were measured to assess the influence of UA on the cell membrane. Our results show that UA was effective against CRKP at an MIC of 0.8 mg ml. UA disrupted the cell membrane integrity of CRKP, exhibited strong inhibitory effects against biofilm formation and biofilm-related gene expression, and inactivated CRKP cells encased in biofilms. Thus, UA shows promise for use in combination with other antibiotics to treat multidrug resistant K. pneumoniae infections.
先前的研究表明，苹果渣中的熊果酸（UA）对一些微生物具有抗菌活性，但与这种活性相关的潜在机制仍未得到探索。此外，目前尚无关于 UA 对耐碳青霉烯类肺炎克雷伯菌（CRKP）影响的报道。本研究旨在探讨 UA 对 CRKP 的抗菌活性及其作用机制。采用琼脂稀释法测定 UA 对 CRKP 的最小抑菌浓度（MIC）。测量细胞内 pH 值（pHin）、ATP 浓度和细胞膜电位的变化，以评估 UA 对细胞膜的影响。结果表明，UA 在 MIC 为 0.8mg/ml 时对 CRKP 有效。UA 破坏了 CRKP 的细胞膜完整性，对生物膜形成和生物膜相关基因表达具有很强的抑制作用，并使包被在生物膜中的 CRKP 细胞失活。因此，UA 有望与其他抗生素联合用于治疗多重耐药性肺炎克雷伯菌感染。
