Salmonella enterica serovar Enteritidis live vaccine strain in the reproductive organs of laying goose after subcutaneous vaccination

Serovar-specific real-time PCR for Salmonella enterica serovar Enteritidis (S. Enteritidis) was conducted to detect the genomic DNA of S. Enteritidis from laying goose after subcutaneous vaccination at different time points. Indirect fluorescent antibody (IFA) technique and immunohistochemical localization were employed to validate the results. The results showed that S. Enteritidis was consistently detected in all the samples. Vagina and uterus were positive at 20 h PI، and the last organ to show a positive result was the largest and third largest preovulatory follicle، at 32 h PI. The copy numbers of S. Enteritidis DNA in each tissue reached a peak at 36-60 h PI، with the vagina and uterus containing higher concentrations than other tissues. However، the number of bacteria started decreasing by 3-4 d، and by 6 d، the concentration of S. Enteritidis DNA was below the detection limits of the PCR assay، except the vagina. The real-time PCR analysis of a variety of tissues is significant for further investigation of the mechanism of vaccine protection and the optimization of vaccination regimes.