Construction, molecular characterization, and safety assessment of mutant of Gallinarum.

This study involves the development and molecular characterization of the isogenic markerless knockout mutant SG Δ, a genetically engineered live attenuated strain aimed at controlling Gallinarum (SG) infection in poultry. The mutant was generated by deleting the gene using -Red recombination technology, impairing adenylosuccinate lyase, necessary for purine biosynthesis. An 1,180 bp deletion was engineered within the gene, leaving a residual 298 bp genomic scar resulting in a purine auxotrophic mutant.

Pathogenic diversification of the gut commensal via acquisition of a second type III secretion system.

is a Gram-negative bacterium found in various water and land environments and organisms, including insects and mammals. Some strains encode gene homologs of virulence factors found in pathogenic Enterobacterales members, such as serovar Typhimurium and . Whether these genes are pathogenic determinants in is not known.

Pathogenic diversification of the gut commensal via acquisition of a second type III secretion system.

is a Gram-negative bacterium found in a wide variety of water and land environments and organisms. It has been isolated as part of the gut microbiome of animals and insects, as well as from stool samples of patients with diarrhea. Specific strains encode gene homologs of virulence factors found in other pathogenic members of the same Enterobacterales order, such as serovar Typhimurium and Whether these genes are also pathogenic determinants in is not known.

Ecotin protects Typhimurium against the microbicidal activity of host proteases.

Unlabelled: serovar Typhimurium causes acute diarrhea upon oral infection in humans. The harsh and proteolytic environment found in the gastrointestinal tract is the first obstacle that these bacteria face after infection. However, the mechanisms that allow to survive the hostile conditions of the gut are poorly understood.

Bacterial resistance to temperate phage is influenced by the frequency of lysogenic establishment.

Temperate phages can shape bacterial community dynamics and evolution through lytic and lysogenic life cycles. In response, bacteria that resist phage infection can emerge. This study explores phage-based factors that influence bacterial resistance using a model system of temperate P22 phage and both inside and outside the mammalian host.