Bacterial factors affecting macrophage survival and induction of immune responses in avian host-specific serovar S. Pullorum

PhD Student: Xiao Fei
Thesis defended: 24 August 2022

Salmonella enterica is an important pathogen infecting humans and warm blooded animals. Some serovars infect a broad range of hosts (host-generalist), such as the commonly known S. Enteritidis (SE) and S. Typhimurium, while others specifically infect one or a narrow range of host(s) (host-specific), such as S. Pullorum (SP), S. Typhi and S. Dublin. Different from the host-generalist serovars, the host-specific ones are more likely to cause acute systemic infection, which is associated with a distinct host immune response. Although SP and SE are genetically similar, their pathogenicity and host range are vastly different. SP specifically infects chicken, where it causes acute systemic infection in young chicken, and may establish persistent infection with a Th2-biased immune response. SE is a typical host-generalist serovar. It mainly causes gastroenteritis, and it induces a Th1-biased immune response. It is currently unknown which factors of bacteria that contribute to these different modulations of the immune response. The genomic difference between SP and SE could be a valuable source of information to assist in the identification of the bacterial factor(s) responsible for the phenotypic differences between the two serovars.

The aim of the PhD project was to develop bioinformatics tools that could be used together with molecular bacteriology techniques to identify and characterize the bacterial factor(s) responsible for differences in immune responses in the avian host when infected with the two serovars S. Pullorum and S. Enteritidis.

This PhD project developed novel bioinformatics tools which, together with molecular bacteriology techniques, assist researchers in identifying and characterizing the bacterial factor(s) responsible for differences in immune responses in avian hosts infected with the two serovars SP and SE.