Impact of yihO/Q deletion in O-Antigen capsule formation, environmental stress mitigation, and intracellular virulence, survival and replication of Salmonella Typhimurium. Impact of yihO/Q deletion in O-Antigen capsule formation, environmental stress mitigation, and intracellular virulence, survival and replication of Salmonella Typhimurium

This study characterized the involvement of yihO and yihQ of yih operon associated with O-antigen capsule formation, in phenotypic characteristics, intracellular survival, and virulence in Salmonella Typhimurium (ST). Bacterial fitness screening of the ∆yihO, ∆yihQ, and ∆yihO/Q ST mutants showed impairment in biofilm formation, motility, starvation, and stress survival. In vitro studies using phagocytic and non-phagocytic cells revealed a significant decrease in bacterial invasion and intracellular replication, particularly by the ∆yihO and ∆yihO/Q ST which correlated with the lack of proliferation ability in vivo as observed in the liver and spleen colonization. Transcriptome analysis of the ∆yihO mutant further revealed the downregulation of several genes associated with key processes such as flagellar assembly, Salmonella infection, and T3SS protein secretion such as SPI-1 and SPI-2. This evidence expands the role of yihO as an essential gene for maintaining Salmonella’s environmental resilience and virulence. Overall design: To investigate the possible regulatory role of yihO in Salmonella Typhimurium, the gene was deleted by lambda red recombination method; differentially expressed gene analysis was performed against the Salmonella Typhimurium wild-type using data obtained from RNA-seq