Effect of low and high doses ofSalmonella enteritidis PT4 on experimentally infected chicks

Abstract

Chicks (1-d-old, three groups, each containing 50 chicks) were inoculated with 2 x 10(2) and 2 x 10(8) CFU of Salmonella enteritidis; the third group were kept as uninoculated control. Five birds from each group were euthanized at intervals from 6 h to 4 weeks post-inoculation (pi). In the low-dose group S. enteritidis was isolated from 60% cecal samples at 18 h pi, and from 20% of livers at 3 d pi. Individual variation in the frequency of S. enteritidis recovery was observed in this group. The clearance of salmonella from the organs was faster in the low-dose group, and salmonella was not isolated from the liver and cecum at 21 and at 27 d pi, respectively. However, in the high-dose group, S. enteritidis was isolated from all ceca and 80% of liver 6 h pi, and salmonella was detected in the cecum and liver throughout the experiment. Serous typhlitis and unabsorbed yolk sac were the most prevalent lesions in both groups. Granulomatous nodules in the cecum were found occasionally in some cases in both inoculated groups, which can play a role as reservoirs in carrier chicks.

Distribution of virulence genes sefC, pefA and spvC in Salmonella Enteritidis phage type 4 strains isolated in Brazil

“…This result is different from that reported by Asheg et al (2), who studied poultry infected with low (2 x 10 2 ) and high dose of SE (2 x 10 8 ). These authors observed that in the first week of infection, continuous colonization of the caecum occurred.…”

Effects of Orally Administered Bdellovibrio bacteriovorus on the Well-Being and Salmonella Colonization of Young Chicks

“…It has been published previously by others that the Salmonella Enteritidis PT4 infection of chicks causes full white ceca due to infiltration by white blood cells (1,2,16,36,42). We found these cecal abnormalities in our studies.…”

“…3). In addition, only birds treated with predatory wild-type Bdellovibrio had a significantly smaller proportion of abnormal ceca (which showed inflammatory characteristics described previously [1,2,16,36,42]) than that of untreated controls (Table 1 and Fig. 4).…”

“…That many of the Salmonella-treated birds which did not receive predatory Bdellovibrio had pale ceca with abnormal dense white mucoid gut material within suggested that the untreated Salmonella had caused the inflammation of the ceca and recruitment of heterophils to that area of the gut, as others have reported (1,2,16,36,41,42). It was marked how treatment with predatory Bdellovibrio, but not the ⌬pilA strain, had ameliorated this effect (Table 1 and Fig.…”

“…The horizontal line represents the means for each group. (1,2,16,36,42) to cause pale ceca with dense nonfree-flowing contents due to inflammation and white blood cell infiltration. a Shown are the number of cecal abnormalities in each treatment group on each day following treatment.…”