Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (S. Gallinarum) is the biologic agent of fowl typhoid, a grave disease that takes place in birds of any age though it is more common in adults. Salmonella enterica subsp. enterica serovar Gallinarum biovar Pullorum (S. Pullorum) is the pathogen causative of pullorum disease, a systemic illness that occurs mainly in young birds. The bacterium may induce a carrier state in some of them and is able to be transmitted vertically to progeny. Both bacteria are genetically and phenotypically similar, but showing distinct pathogenicity and epidemiology. It is believed that their ability to differentially modulate host immune response associated with some pathogenicity island two (SPI-2) intrinsic factors would be linked to differences observed in pathogenesis. During to our master's degree study, when we compared these bacteria whole genomes, we did not observe any structural modification or divergence in virulence genes content. Nevertheless, it was seen in metabolism genes. Some studies have shown that different bacterial metabolisms lead to distinct regulation of their virulence genes. Here, we aim to build and assess S. Gallinarum mutant strains defective to some metabolism genes which are naturally inactivated at S. Pullorum genome. We will still assess the capability of them to cause mortality, induce carrier state in chickens infected at 5º day-old and the sort of immune response which will be triggered at the spleen and cecal tonsils during to the course of infection.
News published in Agência FAPESP Newsletter about the scholarship: