title: Parenteral administration of attenuated Salmonella Typhimurium ΔznuABC is protective against salmonellosis in piglets.
abstract: A major cause of salmonellosis in humans is the contamination of pork products. Infection in pigs can be controlled using bio-security programs, but they are not sufficient in countries where a high level of infection is recorded. In this context, the use of vaccines can represent a valid supplementary method of control. Recently, we have demonstrated that an attenuated strain of Salmonella enterica serovar Typhimurium (Salmonella Typhimurium ΔznuABC) is protective against systemic and enteric salmonellosis in mouse and pig infection models, candidating this strain as an oral attenuated vaccine. In this study, we compared the efficacy of this attenuated Salmonella Typhimurium strain when administered orally or parenterally. Furthermore, in order to reproduce a pseudo-natural infection model, vaccinated pigs were allocated in the same pen with animals shedding virulent Salmonella Typhimurium. Animals were monitored weekly after vaccination and contact with infected piglets. Diarrhea and ataxia were recorded and Salmonella shedding was tested individually through bacterial culture. After four weeks of cohousing, piglets were euthanized, after which lymph nodes reactivity and gross lesions of the gut sections were scored at necropsy. Organs were submitted to microbiological and histological analyses. The data reported herein show that parenterally vaccinated animals do not shed the attenuated strain, and at the same time the absence of symptoms and decrease in virulent strain shedding in feces from day 6 after challenge demonstrated protection against infection induced by virulent Salmonella Typhimurium. In conclusion, our findings suggest that this is an alternative route of Salmonella Typhimurium ΔznuABC administration, without ignoring the advantages associated with oral vaccination.
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Ruggeri
authors.affiliation: Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, 00161 Rome, Italy; FAO Reference Center for Veterinary Public Health, Italy; VISAVET Health Surveillance Centre, Universidad Complutense Madrid, 28040 Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Pesciaroli
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Gaetarelli
authors.affiliation: Department of Veterinary Sciences, Università degli Studi di Torino, 10095 Torino, Italy.
authors.forename: F E
authors.initials: FE
authors.lastname: Scaglione
authors.affiliation: Department of Veterinary Sciences, Università degli Studi di Torino, 10095 Torino, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pregel
authors.affiliation: Department of Biology, Università di Roma Tor Vergata, 00133 Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Ammendola
authors.affiliation: Department of Biology, Università di Roma Tor Vergata, 00133 Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Battistoni
authors.affiliation: Department of Veterinary Sciences, Università degli Studi di Torino, 10095 Torino, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Bollo
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy.
authors.forename: G L
authors.initials: GL
authors.lastname: Alborali
authors.affiliation: Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, 00161 Rome, Italy; FAO Reference Center for Veterinary Public Health, Italy. Electronic address: paolo.pasquali@iss.it.
authors.forename: P
authors.initials: P
authors.lastname: Pasquali
mesh_terms: D000284:Administration, Oral; D000818:Animals; D057138:Bacterial Shedding; D004306:Dose-Response Relationship, Immunologic; D005243:Feces / Q000382:microbiology; D007273:Injections, Intramuscular; D012481:Salmonella Infections, Animal / Q000517:prevention & control*; D022562:Salmonella Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D012486:Salmonella typhimurium; D034421:Sus scrofa / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D022562:Salmonella Vaccines; D014613:Vaccines, Attenuated
keywords: Piglets; Pseudo-infection model; Salmonella; Vaccine