Populations of Salmonella enteritidis in the Tissues of Reproductive Organs in Laying Hens After Oral Challenge: A Real-Time PCR Study

The objective of this study was to determine the populations of Salmonella enteritidis (S. enteritidis) in reproductive organs of laying hens after oral challenge. Researchers conducted serovar-specific Real-time PCR for S. enteritidis to detect the genomic DNA of S. enteritidis from laying hens at different time points. To validate these results, the Indirect Fluorescent Antibody (IFA) technique was employed too. 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 days and by 6 days, the concentration of S. enteritidis DNA was below the detection limits of the PCR assay except the vagina. In conclusion, the results provided insights into the S. enteritidis populations in the reproductive organs. This study will help in understanding the pathogenesis of S. enteritidis infection in vivo.