ATC vet code: QI01AE01
To stimulate active immunity to Salmonella Enteritidis, phage type 4.
The vaccine strain is a natural metabolic drift mutant, i.e. it lacks or does not express certain metabolic pathways which result in attenuation.
The genetic basis results in defective ribosomal protein S12 affecting polypeptide synthesis (streptomycin resistance) and defective RNA polymerase affecting transcription of DNA to RNA (rifampicin resistance).
The vaccine strain also has attenuations that increase the permeability of the cell membrane to noxae such as detergents and antibiotics. This means the strain has poor survival in the environment and is highly sensitive to fluoroquinolones and unlike field strains is sensitive to erythromycin.