Effects of Salmonella enterica serovar Enteritidis pathogenicity island ROD21 on the expression of virulence genes

Previous studies from our laboratory have shown that deletion of ROD21 can affect the virulence of SEn. We observed that both the deletion of ROD21 and the joined deletion of SEN1970 and SEN1998 have an impact on the transcriptional pattern of SEn in vitro.

We observed changes in the transcription of genes located in SPI-2, which are required for intracellular survival and colonization. We also found that in both cases, genes related to the expression of flagellar machinery are downregulated, which could also be observed in the bacterial morphology in vitro. This observation was later backed up with in vivo experiments in mice, which showed a differential capacity of SEn ROD21 mutant strains to reach levels of colonization at later stages of infection, compared to the wild-type SEn strain.