Differences in Abilities to Colonize Reproductive Organs and to Contaminate Eggs in Intravaginally Inoculated Hens and in vitro Adherences to Vaginal Explants between Salmonella enteritidis and Other Salmonella Serovars

Abstract

In Experiment 1, mature laying hens were inoculated intravaginally with 10(6) colony-forming units of Salmonella enterica serovar enteritidis (S. enteritidis), Salmonella typhimurium, Salmonella infantis, Salmonella hadar, Salmonella heidelberg, or Salmonella montevideo to compare their abilities to colonize the reproductive organs of chickens and to contaminate eggs. Salmonella enteritidis was more frequently recovered (from 11 of 40 eggs, 27.5%) than the other serovars, and especially the inner shell was contaminated with these organisms in 10 of 40 eggs (25.0%). The contamination rates and the viable counts in cloaca were significantly (P < 0.05) higher in hens inoculated with S. enteritidis than in those inoculated with the other serovars at 4 days postinoculation (PI). In the vagina, the positive rates were 90%-100% in hens inoculated with S. enteritidis, and the viable counts of the organisms in this portion were significantly (P < 0.05) higher than those of the other serovars at 2, 4, and 7 days PI. The ceca were colonized similarly by each serovar at 7 days PI. The spleen and ovary were infected with S. enteritidis in three and one hen, respectively. No Salmonella was recovered from liver and peripheral blood in any hen. Salmonella enteritidis was recovered from other oviductal portions than the vagina (10%-20%), whereas no forming egg was contaminated in the oviduct. In Experiment 2, the in vitro adherence of these six serovars to the vaginal epithelium was compared with vaginal explants. The mean number of S. enteritidis attaching to the secondary villi in the vaginal lumen was significantly (P < 0.05) higher than those of the other serovars. These results suggest that S. enteritidis has a specific advantage over the other Salmonella serovars by its capacity to colonize the vaginal tissues of hens, and this higher affinity of S. enteritidis to the vagina may play a significant role in the production of many S. enteritidis-contaminated eggs.

Salmonella enterica Serovar Enteritidis Genes Induced during Oviduct Colonization and Egg Contamination in Laying Hens

“…The horizontal transmission route implies Salmonella penetration through the eggshell, after the eggs are covered by the shell (14,42). In contrast, the vertical transmission route refers to direct contamination of the egg content before oviposition, as a result of Salmonella infection of the reproductive organs (48,49). It is believed that the most important route of egg contamination is via infected reproductive tissues, both the oviduct and the ovary (18,33).…”

Scientific Opinion on a quantitative estimation of the public health impact of setting a new target for the reduction of Salmonella in laying hens

“…The contamination rates and the viable counts in the cloaca were also significantly higher in hens inoculated with S. Enteritidis than in those inoculated with the other serovars at 4 days post-inoculation (PI), while the caeca were colonized similarly by each serovar at 7 days PI. Comparison of in vitro adherence of these six serovars using vaginal explants has also confirmed that S. Enteritidis has a specific advantage over the other Salmonella serovars in its capacity to colonise the vaginal tissues of hens, and this higher affinity to the vagina is likely to play a major role in the production of S. Enteritidis contaminated eggs (Okamura et al, 2001). These advantages of S. Enteritidis in long term colonisation of the reproductive organs of hens have been confirmed using different approaches and somewhat different strains (Okamura et al, 2001, Mizumoto, et al, 2005.…”

“…Comparison of in vitro adherence of these six serovars using vaginal explants has also confirmed that S. Enteritidis has a specific advantage over the other Salmonella serovars in its capacity to colonise the vaginal tissues of hens, and this higher affinity to the vagina is likely to play a major role in the production of S. Enteritidis contaminated eggs (Okamura et al, 2001). These advantages of S. Enteritidis in long term colonisation of the reproductive organs of hens have been confirmed using different approaches and somewhat different strains (Okamura et al, 2001, Mizumoto, et al, 2005. Furthermore, it has been established that the mean number of Salmonella in the vaginal epithelium depended on their lipopolysaccharide (LPS) type, with the rank order as follows: LPS type O9 (S. Enteritidis) > LPS type O4 (S. Agona, S. Typhimurium and S. Heidelberg) > LPS type O7 (S. Montevideo and S. Infantis) and LPS type O8 (S. Hadar).…”

Quantitative studies of the regular distribution pattern for Salmonella enteritidis in the internal organs of mice after oral challenge by a specific real-time polymerase chain reaction

“…Simultaneously, it has been reported that chicken macrophages display differences in their responses to S. enteritidis and S. typhimurium, and contribute to the differential pathogenesis of these Salmonella serovars [42] . Also, it has been reported that S. enteritidis infection induce less inflammation resulting in a more commensal, while S. typhimurium infection can be cleared more rapidly by induction of inflammatory [43,44] . S. enteritidis resulted in increased splenic CD3 and reduced B populations, it was difficult to associate this increase with S. enteritidis clearance due to lack of any significant changes in CD4 + of CD8 + cells [45] .The functions of the spleen and liver in filtration, immune responsiveness and activation of complement have been well documented.…”