Non-reverting salmonella

摘要: Salmonella typhimurium strain SL1479, ATCC No. 39183 and dublin SL1438, 39184 are provided which useful as live vaccines. The vaccines prepared by introducing at least one modification in a gene involved one, normally two, biosynthetic pathways, involving the production of products unlikely to be found disease susceptible host. results change cannot repaired single step e.g. polynucleotide deletions inversions. Where aro suffers such change, resultant auxotrophic mutants required aromatic amino acids, p-aminobenzoic acid enterochelin or highly concentrated source absorbable iron. mutations have substantially reduced nonexistent virulence, while retaining desired immunogenicity initiate immunogenic response.