Transcriptional Sequencing Uncovers Survival Mechanisms of Salmonella enterica Serovar Enteritidis in Antibacterial Egg White

Abstract

Salmonella enterica serovar Enteritidis is a major foodborne pathogen that causes salmonellosis mainly through contaminated chicken eggs or egg products and has been a worldwide public health threat since 1980. Frequent outbreaks of this serotype through eggs correlate significantly with its exceptional survival ability in the antibacterial egg white. Research on the survival mechanism of S. Enteritidis in egg white will help to further understand the complex and highly effective antibacterial mechanisms of egg white and lay the foundation for the development of safe and effective vaccines to prevent egg contamination by this Salmonella serotype. Key pathways and genes that were previously overlooked under bactericidal conditions were characterized as being induced in egg white, and synergistic effects between different antimicrobial factors appear to exist according to the gene expression changes. Our work provides new insights into the survival mechanism of S. Enteritidis in egg white.

Role of yoaE Gene Regulated by CpxR in the Survival of Salmonella enterica Serovar Enteritidis in Antibacterial Egg White

“…Through gene deletion and complementary, we demonstrated that seven differently expressed genes (including gene yoaE) obtained from our published transcriptome data contributed to the survivability of S. Enteritidis in egg white (17). Six of them (except gene yoaE) were included in our previous published paper (17).…”

“…Through gene deletion and complementary, we demonstrated that seven differently expressed genes (including gene yoaE) obtained from our published transcriptome data contributed to the survivability of S. Enteritidis in egg white (17). Six of them (except gene yoaE) were included in our previous published paper (17). In this study, gene yoaE (A7J12_06270), which encodes a predicted inner membrane protein and was upregulated by 15-to 18-fold at the mRNA level in egg white (17), was further characterized.…”

“…Previous studies have shown that S. Enteritidis mobilizes utilizes multiple mechanisms to counteract antibacterial factors in egg white. Genes or pathways involved in iron absorption (15)(16)(17), biotin synthesis (16)(17)(18), DNA replication and repair (4,17,19), alkaline pH adaptation (17), osmotic stress adaptation (17), envelope damage repair (including peptidoglycan biosynthesis and remodeling) (4,17), amino acid transport and metabolism (4), lipopolysaccharide metabolism (4,18,20,21), and cell motility (22) were found to be important for S. Enteritidis survival in egg white.…”

“…The two-component regulatory system (TCS) CpxR/A plays a central and critical role in bacterial envelop damage repair and alkaline pH adaption in egg white (16,17). Once activated in egg white, CpxR/A upregulated genes involved in periplasmic space homeostasis, peptidoglycan cross-linking, and remodeling and envelope cross-linking to combat envelope stress caused by egg white; they also upregulated cation/antiporter chaA and downregulated the respiratory complexes (the nuo and cyo operons) to increase proton import and to decrease proton export, therefore maintaining bacterial pH homeostasis in the alkaline egg white (16,17). In addition, deletion of cpxR gene made the survival ability of S. Enteritidis in egg white dramatically reduced, which further proved the importance of this TCS (17).…”

Transcriptomic Analysis, Motility and Biofilm Formation Characteristics of Salmonella typhimurium Exposed to Benzyl Isothiocyanate Treatment

“…For example, the effects of cranberry extract and antimicrobial proteins on the growth rates and transcriptomics of S. typhimurium were investigated. The expressions of related genes, such as those involved in iron acquisition, flagella, energy metabolism, pathogenicity, virulence islands and the cell membrane, were significantly downregulated after bacteriostatic treatment in S. typhimurium [22,23]. According to Song et al and Wang et al [24,25], the transcriptome was used to explore the mechanism of antibacterial activity of BITC on Vibrio parahaemolyticus and Staphylococcus aureus.…”