咖啡酸苯乙酯抑制肺炎克雷伯菌增殖及生物膜形成的分子机制研究OACHSSCD

This study investigated the antibacterial activity of caffeic acid phenethyl ester(CAPE)against Klebsiella pneumoniae and explored its molecular mechanisms in inhibiting biofilm formation.The effects of CAPE on bacterial growth were evaluated by determining the minimum inhibitory concentration(MIC),minimum bactericidal concentration(MBC),and growth curves.Crystal violet staining,adhesion assays,and confocal laser scanning microscopy were used to assess the effects of CAPE on biofilm formation and structure.In addition,leakage of extracellular DNA and proteins,as well as changes in exopolysaccharides content,were quantitatively analyzed.RT-qPCR was performed to determine the expression levels of genes associated with biofilm formation,adhesion,and virulence.The results showed that the MIC and MBC of CAPE against K.pneumoniae were 0.312 5 mmol/L and 0.625 0 mmol/L,respectively,and that CAPE significantly inhibited bacterial growth.At 2 MIC,CAPE effectively removed mature biofilms,a-chieving a removal rate of 50.18%.Meanwhile,bacterial adhesion and exopolysaccharides content were reduced by 73.3%and 46.2%,respectively,and CAPE induced substantial leakage of extracellular DNA and proteins.RT-qPCR analysis further revealed significant downregulation of multiple genes related to biofilm formation.In conclusion,CAPE exhibits potent antibacterial activity against K.pneumoniae by impairing membrane integrity,inhibiting biofilm formation,and modulating the expression of virulence-related genes,supporting its potential as a natural antimicrobial agent.