The aim of this study was to evaluate the protective capacity of an attenuated strain of Salmonella Typhimurium as a vaccine candidate against an experimental challenge. For this purpose, 51 recently weaned female guinea pigs from a commercial farm were used and distributed into three groups of 17 animals each: one group was inoculated with the attenuated strain and challenged, the second group was challenged only, and the third group served as a control (without attenuated strain and without challenge). The animals, according to their respective groups, were immunized after two weeks of adaptation to the new rearing conditions. Five weeks after immunization they were challenged with a virulent strain of S. Typhimurium. The health status was monitored for five weeks post-challenge and fecal samples were collected to demonstrate the excretion of IgA and S. Typhimurium. Additionally, necro...

The present study aims to obtain data that facilitate the design of an animal model that replicates salmonellosis produced by the serovar Typhimurium under experimental conditions by a single dose of streptomycin 50 mg orally 24 hours prior to the challenge with three concentrations of a virulent strain of Salmonella Typhimurium. Female guinea pigs (n=58) were used, distributed in 6 treatment groups of 8 animals each (3 groups to which streptomycin was administered prior to the challenge and 3 groups that were only challenged) and 2 control groups of 5 animals each (1 group treated with streptomycin and unchallenged and another untreated and unchallenged). The doses of the inoculum were 107, 108, 109/ml of S. Thiphimurium per group, respectively, and the animals were monitored for 30 days. Collective stool samples per group were collected to determine the excretion time of S. Typhimurium...

The aim of this study was to evaluate the relative expression of the cytokines involved in the immune response of Th1 (IL-2, IL-12, IFN-γ, TNF-α), Th2 (IL-4, IL-10 and TGF-β) and Th17 (IL-17) in 21 guinea pigs (Cavia porcellus) experimentally inoculated with a field isolate of Salmonella Typhimurium at a dose of 102 CFU/ml, intraperitoneally, and compared with a control group (inoculated with a thermally treated strain). Blood samples were taken on days 1, 3, 5, 7, 9, 15 and 30 post-inoculation (p.i.). Total RNA was extracted from lymphocyte cells and real-time RT-PCR was conducted using specific primers for each of the cytokines. The relative mRNA expressions were determined by the comparative method 2-ΔΔCt with respect to the calibrator (healthy guinea pig) and using GAPDH as a constitutive gene of reference as a normalizer. The expressions of the cytokine genes in the Treatment g...

The aim of this study was to evaluate the relative expression of the cytokines involved in the immune response of Th1 (IL-2, IL-12, IFN-γ, TNF-α), Th2 (IL-4, IL-10 and TGF-β) and Th17 (IL-17) in 21 guinea pigs (Cavia porcellus) experimentally inoculated with a field isolate of Salmonella Typhimurium at a dose of 102 CFU/ml, intraperitoneally, and compared with a control group (inoculated with a thermally treated strain). Blood samples were taken on days 1, 3, 5, 7, 9, 15 and 30 post-inoculation (p.i.). Total RNA was extracted from lymphocyte cells and real-time RT-PCR was conducted using specific primers for each of the cytokines. The relative mRNA expressions were determined by the comparative method 2-ΔΔCt with respect to the calibrator (healthy guinea pig) and using GAPDH as a constitutive gene of reference as a normalizer. The expressions of the cytokine genes in the Treatment g...