AUTHOR=Chang Yunhe , Xing Min , Hu Xinying , Feng Hongxia , Wang Yao , Guo Bingrui , Sun Maocheng , Ma Lizhi , Fei Peng 

TITLE=Antibacterial Activity of Chrysanthemum buds Crude Extract Against Cronobacter sakazakii and Its Application as a Natural Disinfectant

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.632177

DOI=10.3389/fmicb.2020.632177

ISSN=1664-302X

ABSTRACT=<p><italic>Cronobacter sakazakii</italic> is an opportunistic food-borne pathogen that endangers the health of neonates and infants. This study aims to elucidate the antibacterial activity and mechanism of <italic>Chrysanthemum buds</italic> crude extract (CBCE) against <italic>C. sakazakii</italic> and its application as a natural disinfectant. The antibacterial activity was evaluated by the determination of the diameter of inhibition zone (DIZ), minimum inhibitory concentration (MIC), and minimum bactericide concentration (MBC). The antibacterial mechanism was explored based on the changes of growth curve assay, intracellular ATP concentration, membrane potential, intracellular pH (pH<sub>in</sub>), content of soluble protein and nucleic acid, and cell morphology. Finally, the inactivation effects of CBCE against <italic>C. sakazakii</italic> in biofilm on stainless steel tube, tinplate, glass, and polystyrene were evaluated. The results showed that the DIZ, MIC, and MBC of CBCE against <italic>C. sakazakii</italic> were 14.55 ± 0.44–14.84 ± 0.38 mm, 10 mg/mL, and 20 mg/mL, respectively. In the process of CBCE acting on <italic>C. sakazakii</italic>, the logarithmic growth phase of the tested bacteria disappeared, and the concentrations of intracellular ATP, pH<sub>in</sub>, bacterial protein, and nucleic acid were reduced. Meanwhile, CBCE caused the cell membrane depolarization and leakage of cytoplasm of <italic>C. sakazakii</italic>. In addition, about 6.5 log CFU/mL of viable <italic>C. sakazakii</italic> in biofilm on stainless steel tube, tinplate, glass, and polystyrene could be inactivated after treatment with 1 MIC of CBCE for 30 min at 25°C. These findings reveal the antibacterial activity and mechanism of CBCE against <italic>C. sakazakii</italic> and provide a possibility of using a natural disinfectant to kill <italic>C. sakazakii</italic> in the production environment, packaging materials, and utensils.</p>