[Immunization with potential Salmonella enteritidis mutants-- 2. Investigations on the attenuation and immunogenicity for mice and young hens].

Adenine-amino acid auxotrophic Salmonella Enteritidis double mutants were investigated for their in vivo stability, attenuation und immunogenicity using NMRI-mice and SPF-chicks. All mutants used were stable in vivo and attenuated. Two mutants were selected for immunization experiments in chickens according to their protective ability after a single intraperitoneal immunization in NMRI-mice using a homologous and heterologous challenge. After two oral immunizations and homologous oral challenge with the S. Enteritidis wild type strain 6403Nalr, a significant difference (p < 0.01) was demonstrated between the mean caecal bacterial counts of immunized and control chicks. Examination of liver samples revealed a significantly lower degree of colonization of internal organs (p < 0.01) in immunized birds. There was no evidence of cross protection against S. Typhimurium using S. Enteritidis mutants.