CpxAR two-component system contributes to virulence properties of Cronobacter sakazakii

Tong Jin; Xiangjun Zhan; Liuxin Pang; Bo Peng; Xinpeng Zhang; Wenxiu Zhu; Baowei Yang; Xiaodong Xia

doi:10.1016/j.fm.2023.104393

CpxAR two-component system contributes to virulence properties of Cronobacter sakazakii

Food Microbiol. 2024 Feb:117:104393. doi: 10.1016/j.fm.2023.104393. Epub 2023 Oct 11.

Authors

Tong Jin¹, Xiangjun Zhan¹, Liuxin Pang¹, Bo Peng², Xinpeng Zhang², Wenxiu Zhu³, Baowei Yang⁴, Xiaodong Xia⁵

Affiliations

¹ College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
² College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China; Food Science and Technology Department, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
³ State Key Laboratory of Marine Food Processing and Safety Control, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, Liaoning, 116034, China.
⁴ College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China. Electronic address: ybwsheng@nwsuaf.edu.cn.
⁵ College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China; State Key Laboratory of Marine Food Processing and Safety Control, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, Liaoning, 116034, China. Electronic address: xdxia@nwsuaf.edu.cn.

PMID: 37919015
DOI: 10.1016/j.fm.2023.104393

Abstract

Cronobacter sakazakii (C. sakazakii) is a foodborne pathogen which threaten susceptible hosts including infants. CpxA/CpxR, a regulatory two-component system (TSC), contributes to stress response and virulence in various Gram-negative pathogens, but its role in C. sakazakii has not been thoroughly studied. In this study, we constructed CpxA, CpxR, CpxAR deletion and complementation strains. The mutants showed weakened bacterial adhesion to and invasion of HBMEC and Caco-2, reduced intracellular survival and replication of C. sakazakii within RAW264.7 macrophages, and decreased translocation of HBMEC and Caco-2 monolayers. Mutants demonstrated lower levels of tight junction proteins disruption and reduced apoptosis and cytotoxicity in Caco-2 monolayer compared to wild type strain. CpxAR TCS deletion mutants demonstrate attenuated virulence in newborn mice, which was evidenced by fewer bacterial cells loads in tissues and organs, lower levels of intestinal epithelial barrier dysfuction and milder damages in intestinal tissues. All these phenotypes were recovered in complemented strains. In addition, qRT-PCR results showed that CpxAR TCS of C. sakazakii played roles in regulating the expression of several genes associated with bacterial virulence and cellular invasion. These findings indicate that CpxAR TCS is an important regulatory mechanism for virulence of C. sakazakii, which enrich our understanding of genetic determinants of pathogenicity of the pathogen.

Keywords: Cronobacter sakazakii; Gene deletion; Intestinal epithelial barrier; Newborn mice; Virulence genes.

MeSH terms

Animals
Bacterial Adhesion
Caco-2 Cells
Cronobacter sakazakii* / genetics
Cronobacter*
Enterobacteriaceae Infections* / microbiology
Humans
Infant
Mice
Virulence