Inflammatory infection and transmission of β-lactam resistance in a mouse model of ampicillin-induced microbiota. Enterobacteriaceae

Humans and farm animals commonly consume food- or waterborne bacteria that harbour antibiotic resistance genes. The fate and potential horizontal gene transfer of those genes into the host microbiome will have a crucial bearing on the eventual health risk of exposure to antibiotic resistance genes. In the present study, the effects of antibiotics on the in vivo transfer of 𝛽-lactam resistance genes were evaluated in a mouse model by characterizing the microbiome in excreted feces. Mice were dosed with Escherichia coli, Salmonella enterica serovars Heidelberg or Bredeney referred to as donors. The in vivo transfer of the antibiotic resistance genes (blaTEM-1B, blaCMY-2, blaCTX-M1, etc.) from these donor bacteria to an exogenously introduced or endogenously present Escherichia coli strains (i.e. recipients) in the mouse gut was evaluated with or without a clinical dosage of ampicillin.