Virulence evaluation and Differential gene expression in vivo of Salmonella enterica mutants for nucleoid associated proteins

Abstract

Salmonella enterica is a rod-shaped, gram-negative, facultative anaerobic, Enterobacteriaceae family member, responsible for great economic losses and public health problems. It causes disease to humans and animals, ranging from gastroenteritis to systemic infections. Approximately 20 years ago, the Enteritidis serovar became the most present in cases of salmonellosis in Brazil, Europe and the United States, being eggs and other products derived from chicken the main source of infection. One way to control those infections caused by S. enterica is using vaccines, which has already been used in several countries, despite the need of improvement of these. Recent data from our group indicate that null mutants of S. enterica Typhimurium for NAP (Nucleoid-associated proteins) genes, are attenuated for virulence and capable of inducing protection in a murine model of infection. The patents about the development of these strains have been submitted to the INPI. Based on S. enterica Typhimurium recent data from our group, this project proposes the construction of mutants of S. enterica Enteritidis for genes hupA, hupB and the double-mutant hupAhupB through »-Red homologous recombination system, and characterization of those mutants in attenuation of virulence and the immune response generated in a murine model of infection. These are histone-like genes that acts in the global regulation of gene expression, so the differences in gene expression profile of S. Enteritidis new mutants will be analised, as well as the previously constructed in S. Typhimurium, using RNA-seq technique, and the data will be validated by RT-PCR. We hope to obtain important data showing genetic differences between strains, and reflecting the difference between their mechanisms of pathogenicity.