Jiang Xiaobing, Jiang Congyi, Yu Tao, Jiang Xiaojie, Ren Siyu, Kang Rui, Qiu Shuxing
Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China.
School of Life Sciences & Basic Medicine, Xinxiang University, Xinxiang, China.
Front Microbiol. 2022 Feb 23;13:856274. doi: 10.3389/fmicb.2022.856274. eCollection 2022.
Benzalkonium chloride (BC) is widely used for disinfection in food industry. However, prolonged exposure to BC may lead to the emergence of BC adapted strains of , an important foodborne pathogen. Until now, two communication systems, the LuxS/AI-2 system and the Agr system, have been identified in . This study aimed to investigate the role of communication systems in BC adaptation and the effect of BC adaptation on two communication systems and the communication-controlled behaviors in . Results demonstrated that the Agr system rather than the LuxS system plays an important role in BC adaptation of . Neither expression nor AI-2 production was affected by BC adaptation. On the other hand, the expression of the operon and the activity of the promoter were significantly increased after BC adaptation. BC adaptation enhanced biofilm formation of . However, swarming motility was reduced by BC adaptation. Data from qRT-PCR showed that flagella-mediated motility-related genes (, , and ) were downregulated in BC adapted strains. BC adaptation increased the ability of to adhere to and invade Caco-2 cells but did not affect the hemolytic activity. Compared with the wild-type strains, the expression levels of virulence genes , , , , and increased more than 2-fold in BC adapted strains; however, lower than 2-fold changes in the expression of hemolysis-associated gene were observed. Our study suggests that BC adaptation could increase the expression of the Agr system and enhance biofilm formation, invasion, and virulence of , which brings about threats to food safety and public health. Therefore, effective measures should be taken to avoid the emergence of BC adapted strains of .
苯扎氯铵（BC）在食品工业中广泛用于消毒。然而，长时间接触BC可能导致重要食源性病原体[具体菌名未给出]的BC适应菌株出现。到目前为止，已在[具体菌名未给出]中鉴定出两种通讯系统，即LuxS/AI-2系统和Agr系统。本研究旨在调查通讯系统在BC适应中的作用以及BC适应对两种通讯系统和[具体菌名未给出]中通讯控制行为的影响。结果表明，Agr系统而非LuxS系统在[具体菌名未给出]的BC适应中起重要作用。BC适应既不影响[具体菌名未给出]的表达也不影响AI-2的产生。另一方面，BC适应后，[具体菌名未给出]操纵子的表达和[具体启动子名称未给出]启动子的活性显著增加。BC适应增强了[具体菌名未给出]的生物膜形成。然而，BC适应降低了群体运动性。qRT-PCR数据显示，鞭毛介导的运动相关基因（[具体基因名称未给出]、[具体基因名称未给出]和[具体基因名称未给出]）在BC适应菌株中下调。BC适应增加了[具体菌名未给出]粘附和侵袭Caco-2细胞的能力，但不影响溶血活性。与野生型菌株相比，BC适应菌株中毒力基因[具体基因名称未给出]、[具体基因名称未给出]、[具体基因名称未给出]、[具体基因名称未给出]和[具体基因名称未给出]的表达水平增加了2倍以上；然而，溶血相关基因[具体基因名称未给出]的表达变化低于2倍。我们的研究表明，BC适应可增加Agr系统的表达并增强[具体菌名未给出]的生物膜形成、侵袭和毒力，这对食品安全和公众健康构成威胁。因此，应采取有效措施避免[具体菌名未给出]的BC适应菌株出现。
