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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Cell. Infect. Microbiol. | doi: 10.3389/fcimb.2019.00304

Inhibitory effect of TQ on Listeria monocytogenes ATCC 19115 biofilm formation and virulence attributes critical for human infection

 Xin Miao1,  Huanhuan Liu1, Yangyang Zheng1,  Du Guo1,  Chao Shi1*, Yunfeng Xu2 and  Xiaodong Xia3
  • 1College of Food Science and Engineering, Northwest A&F University, China
  • 2College of Food and Bioengineering, Henan University of Science and Technology, China
  • 3Sino-US Joint Research Center for Food Safety, Ministry of Science and Technology, China

This study aimed to determine the antimicrobial activity of thymoquinone (TQ) against L. monocytogenes, and to examine its inhibitory effects on biofilm formation, motility, hemolysin production, and attachment-invasion of host cells. The minimum inhibitory concentrations (MICs) of TQ against eight different L. monocytogenes strains ranged from 6.25–12.50 μg/mL. Crystal violet staining showed that TQ clearly reduced biofilm biomass at sub-MICs in a dose-dependent manner. Scanning electron microscopy suggested that TQ inhibited biofilm formation on glass slides and induced an apparent collapse of biofilm architecture. At sub-MICs, TQ effectively inhibited the motility of L. monocytogenes ATCC 19115, and significantly impacted adhesion to and invasion of human colon adenocarcinoma cells as well as the secretion of listeriolysin O. Supporting these findings, real-time quantitative polymerase chain reaction analysis revealed that TQ down-regulated the transcription of genes associated with motility, biofilm formation, hemolysin secretion, and attachment-invasion in host cells. Overall, these findings confirm that TQ has the potential to be used to combat L. monocytogenes infection.

Keywords: Listeria monocytogenes, Thymoquinone, Biofilm formation, hemolysin, gene transcription

Received: 14 May 2019; Accepted: 07 Aug 2019.

Copyright: © 2019 Miao, Liu, Zheng, Guo, Shi, Xu and Xia. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Chao Shi, College of Food Science and Engineering, Northwest A&F University, Yanling, China, meilixinong@nwsuaf.edu.cn