Project description:Investigation of whole genome gene expression differences between a full (four-gene) SlrV locus 1 deletion compared to the WT PittII strain. Removal of the four SlrV genes (aka macrophage survival factors : Δmsf) results in a competetive defect with the WT strain in in vitro biofilms and in the otitis media chinchilla model. It also results in an inability to persist within macrophages long-term in vitro and to escape from the middle-ear space and infect other sites in the chinchilla model.