Method of reducing egg contamination

Abstract

The present invention relates to Salmonella mutant strains and their use as a vaccine for preventing Salmonella infection, in particular in eggs.

1 . A method of immunizing a subject against  Salmonella  infection comprising administering a  Salmonella  mutant strain of the serovar  Salmonella enterica  subsp. Enterica, said mutant strain comprising a genetic modification in the tolC gene or in at least the acrAB, acrEF and mdtABC gene, and wherein said mutant strain is capable of preventing or reducing  Salmonella  colonization of the reproductive organs in said hens. 
     
     
         2 . The method according to  claim 1 , wherein the genetic modification is a deletion of at least a portion of the tolC gene or the acrAB, acrEF and mdtABC genes, or wherein the genetic modification results in the inactivation of said gene(s). 
     
     
         3 . The method according to  claim 1 , wherein the  Salmonella  mutant strain is selected from the serogroup B, C or D. 
     
     
         4 . The method according to  claim 1 , wherein the strain is selected from the group consisting of  Salmonella enterica  subsp.  enterica  serovar Enteritidis,  Salmonella enterica  subsp.  enterica  serovar Typhimurium,  Salmonella enterica  subsp.  enterica  serovar Hadar,  Salmonella enterica  subsp.  enterica  serovar Virchow,  Salmonella enterica  subsp. e nterica  serovar Infantis,  Salmonella enterica  subsp.  enterica  serovar Kentucky,  Salmonella enterica  subsp.  enterica  serovar Bredeney,  Salmonella enterica  subsp.  enterica  serovar Agona,  Salmonella enterica  subsp.  enterica  serovar Paratyphi B and  Salmonella enterica  subsp.  enterica  serovar Gallinarum. 
     
     
         5 . The method according to  claim 1 , wherein the mutant strain is part of a vaccine composition further comprising a pharmaceutically acceptable carrier and/or diluent, and optionally an adjuvant. 
     
     
         6 . The method according to  claim 1 , wherein the mutant strain is part of a formulation suitable for administration by injection, inhalation, or oral administration. 
     
     
         7 . The method according to  claim 1 , wherein the strain or composition is administered in a prime-boost regimen. 
     
     
         8 . The method according to  claim 1 , wherein the subject is a broiler hen or a laying hen. 
     
     
         9 . The method according to  claim 8 , wherein said immunized hen produces eggs substantially free of  Salmonella.    
     
     
         10 . A method of preventing or reducing  Salmonella  contamination of eggs, said method comprising administering a  Salmonella  mutant strain comprising a genetic modification in the tolC gene or in at least the acrAB, acrEF and mdtABC gene to layings hens.