Salmonella enterica serotype Dublin is an important bacterial cause of infectious abortion in cattle. Previous work has shown the systemic dissemination of S. Dublin in orally challenged animals to various tissues, including the liver, spleen, and the reproductive tract. Ungulate placentation involves interdigitating maternal (caruncular) and foetal (cotyledonary) tissues in “button-like” structures called placentomes. Bovine caruncular epithelial cells (BCECs) isolated from the maternal caruncular tissues have been used to model the reproductive tract in this study.
The aim of this study was to characterise the invasion and survival of Salmonella Dublin within BCECs, to further our understanding of the mechanisms behind infectious abortions in cattle.
S. Dublin with insertion mutations in genes of the Salmonella Pathogenicity Island (SPI), a Type 3 Secretion System (T3SS), as well as wild-type S. Dublin were used to infect BCECs for 2 to 24 hours. SopB, SopE, SopC, SopD and SipB mutants were used to determine their importance as virulence genes in the infection of bovine placental cells, and the intracellular bacteria were quantified.
S. Dublin is able to invade and replicate within the BCEC cell line. Preliminary results suggest that SipB and SopC mutants were attenuated in their ability to infect and replicate within the cells, whilst SopD mutants were unaffected.
This study was the first to characterise the invasion of bovine caruncular epithelial cells with Salmonella Dublin. This approach allows investigation of aspects of S. Dublin tissue tropisms within the bovine placenta which may lead to abortion.