Antibacterial mechanism of Cu2+–ZnO/cetylpyridinium–montmorillonite in vitro

Cu2+–ZnO/cetylpyridinium–montmorillonite (CZCM) were prepared to investigate the antibacterial mechanism in vitro using pathogenic Escherichia coli and Salmonella typhimurium. CZCM inhibited the growth of E. coli and S. typhimurium. The minimum inhibitory concentrations and minimum bactericidal concentrations of CZCM for E. coli were 80 μg ml− 1 and 160 μg ml− 1, and for S. typhimurium 40 μg ml− 1 and 160 μg ml− 1. CZCM destroyed the bacterial wall and changed the cellular morphology and the efflux of the intracellular components. The intracellular K+ and enzyme were significantly (P < 0.05) released from the bacterial cells after CZCM addition. Oxygen consumption of the bacteria showed that CZCM had a negative effect on the tricarboxylic acid pathway of the bacterial respiratory metabolism. Light had a no significant influence on the antibacterial activity of CZCM.

Research Highlights
► CZCM were prepared using Cu2+, Zn2+, cetylpyridinium, and montmorillonite.
► This material exhibited a highly antibacterial activity to pathogenic bacteria.
► CZCM destroyed the bacterial wall and changed the cellular morphology.
► CZCM had a negative effect on the bacterial respiratory metabolism.
► Thus, CZCM may be used as an antibacterial agent to control the bacterial infection.