Persistence of commensal multidrug-resistant in the broiler production pyramid is best explained by strain recirculation from the rearing environment.

Despite the success of mitigation policies in several countries to reduce the use of antibiotics in veterinary medicine, pathogenic and commensal bacteria resistant to antibiotics are still circulating in livestock animals. However, factors contributing the most to antimicrobial resistance (AMR) persistence in these settings are yet not clearly identified. The broiler production, with its highly segmented, pyramidal structure offers an ideal context to understand and control the spread of resistant bacteria.

Major primary bile salts repress serovar Typhimurium invasiveness partly via the efflux regulatory locus .

Bile represses serovar Typhimurium (. Typhimurium) intestinal cell invasion, but it remains unclear which bile components and mechanisms are implicated. Previous studies reported that bile inhibits the RamR binding to the promoter, resulting in increased transcription, and that overexpression is associated to decreased expression of type III secretion system 1 (TTSS-1) invasion genes and to impaired intestinal cell invasiveness in .