Alteration of Salmonella enterica Virulence and Host Pathogenesis through Targeting sdiA by Using the CRISPR-Cas9 System

is a common cause of many enteric infections worldwide and is successfully engineered to deliver heterologous antigens to be used as vaccines. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) RNA-guided Cas9 endonuclease is a promising genome editing tool. In the current study, a CRISPR-Cas9 system was used to target that encodes signal molecule receptor SdiA and responds to the quorum sensing (QS) signaling compounds N-acylhomoserine lactones (AHLs). For this purpose, was targeted in both wild type (WT) and the Δ mutant strain, where SsaV has been reported to be an essential component of SPI2-T3SS. The impact of mutation on virulence was evaluated at both early invasion and later intracellular replication in both the presence and absence of AHL. Additionally, the influence of mutation on the pathogenesis WT and mutants was investigated in vivo, using mice infection model. Finally, the minimum inhibitory concentrations (MICs) of various antibiotics against strains were determined. Present findings show that mutation in significantly affects biofilm formation, cell adhesion and invasion. However, mutation did not affect bacterial intracellular survival. Moreover, in vivo bacterial pathogenesis was markedly lowered in Δ in comparison with the wild-type strain. Significantly, double-mutant and attenuated the virulence and in vivo pathogenesis. Moreover, mutations in selected genes increased susceptibility to tested antibiotics, as revealed by determining the MICs and MBICs of these antibiotics. Altogether, current results clearly highlight the importance of the CRISPR-Cas9 system as a bacterial genome editing tool and the valuable role of SdiA in virulence. The present findings extend the understanding of virulence regulation and host pathogenesis of .