Comparative proteome and transcriptome analyses of wild-type and live vaccine strains of Salmonella enterica serovar Gallinarum

► We examined molecular correlates of attenuation of a live vaccine strain SG 9R. ► We compared proteomes and transcriptomes of virulent wild-type strains and SG 9R. ► Proteome analysis identified one protein relevant to virulence and absent in SG 9R. ► Transcriptome analysis revealed 42 virulence genes down-regulated in SG 9R.