title: An attenuated Salmonella Enteritidis strain derivative of the main genotype circulating in Uruguay is an effective vaccine for chickens.
abstract: We have recently reported that Salmonella enterica serovar Enteritidis (S. Enteritidis) strains circulating in Uruguay, are unevenly distributed among different genetic subtypes, with a predominant genotype that is a common contaminant of poultry-derived food and that accounts for the vast majority of human cases of food-borne disease. Herein, we describe the construction of a genetically-defined aroC derivative (LVR02) of a local strain of S. Enteritidis belonging to the major genetic type. We demonstrated the attenuation and the immunogenicity of that strain in a mouse model, and evaluated it as a vaccine for commercial layer chickens. LVR02 proved to be stable, attenuated, innocuous, immunogenic and to induce protective immunity against a S. Enteritidis challenge when used for oral vaccination. A single oral dose of LVR02 administered to newly hatched chickens induced protection against oral challenge with the parental virulent strain, preventing systemic and persistent intestinal infection and significantly reducing the shedding of the challenge strain in birds' feces. A second vaccine dose at 15 days post-hatching boosted the immunogenicity of the vaccine, and strengthened the protection achieved with a single dose. This strain may represent the basis of a live vaccine to be included in national control programs to reduce circulation of this pathogen in the country.
authors.affiliation: Laboratory for Vaccine Research, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Uruguay. Av. Alfredo Navarro 3051, CP 11600, Montevideo, Uruguay.
authors.forename: L
authors.initials: L
authors.lastname: Betancor
authors.forename: F
authors.initials: F
authors.lastname: Schelotto
authors.forename: M
authors.initials: M
authors.lastname: Fernandez
authors.forename: M
authors.initials: M
authors.lastname: Pereira
authors.forename: A
authors.initials: A
authors.lastname: Rial
authors.forename: J A
authors.initials: JA
authors.lastname: Chabalgoity
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology; D002645:Chickens; D003257:Consumer Product Safety; D004195:Disease Models, Animal; D005838:Genotype; D006801:Humans; D007928:Lethal Dose 50; D051379:Mice; D008807:Mice, Inbred BALB C; D019761:Phosphorus-Oxygen Lyases / Q000235:genetics; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D011202:Poultry Products / Q000382:microbiology; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D012477:Salmonella enteritidis / Q000145:classification / Q000235:genetics / Q000276:immunology*; D014583:Uruguay; D014613:Vaccines, Attenuated / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated; C019895:chorismate synthase; D019761:Phosphorus-Oxygen Lyases