|QIN, XIAOJIE - University Of Shanghai|
|SHI, XIANMING - Shanghai Jiaotong University|
Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2021
Publication Date: 12/20/2021
Citation: Qin, X., Liu, Y., Shi, X. 2021. Resistance-nodulation-cell division (RND) transporter AcrD confers resistance to egg white in Salmonella Enteritidis. Foods. Availble online: Foods 2022, 11, 90. https://doi.org/10.3390/foods11010090. https://doi.org/10.3390/foods11010090.
Interpretive Summary: Salmonella is an important foodborne pathogen that causes a disease known as salmonellosis. Salmonella can be present as a contaminant in eggs and egg products. A transporter is a protein located in the bacterial membrane that transports drugs in and out of a bacterium. In this study, the role of a transporter found in Salmonella called AcrD was investigated. To accomplish this, the gene that encodes the AcrD protein was deleted from the bacterial genome (the bacterium’s complete set of genetic instructions). The deletion mutant strains showed decreased resistance to egg white, which has antibacterial properties. Furthermore, the deletion mutant strain showed a lower ability to attach to human cells. Taken together, these results indicate the importance of the AcrD transporter on the survival of Salmonella in egg white and its disease-causing potential. This information will lead to the development of strategies for control of Salmonella in eggs and egg products.
Technical Abstract: The excellent survival ability of Salmonella enterica serovar Enteritidis (S. Enteritidis) in antibacterial egg white leads to Salmonella outbreaks frequently associated with eggs and egg products. Our previous proteomic study showed that the expression of multidrug efflux RND transporter AcrD in S. Enteritidis was significantly upregulated (4.06-fold) in response to egg white environment. In this study, the role of AcrD in the resistance and virulence of S. Enteritidis to egg white was explored by gene deletion, survival ability test, morphological observation, and Caco-2 cell adhesion and invasion. It was found that deletion of acrD had no apparent effect on the growth of S. Enteritidis in Luria-Bertani broth, but resulted in a significant decrease in resistance of S. Enteritidis to egg white (P < 0.05) and a small amount of cell lysis. Compared to the wild type, a 2-log population reduction was observed in the 'acrD mutant with an initial concentration of 103 CFU/ml or 106 CFU/ml after incubation with egg white for 3 days. Furthermore, no significant (P > 0.05) difference in the adhesion and invasion was found between the wild type and 'acrD mutant in LB broth and egg white, but the invasion ability of 'acrD mutant in egg white was significantly (P < 0.05) lower than that in LB broth. Taken together, these results revealed the importance of AcrD on the survival and virulence of S. Enteritidis in egg white.