Cloning vectors and fluorescent proteins can significantly inhibit Salmonella enterica virulence in both epithelial cells and macrophages: implications for bacterial pathogenesis studies.

Plasmid vectors and fluorescent protein reporter systems are commonly used in the study of bacterial pathogenesis. Here we show that they can impair the ability of Salmonella enterica serovar Typhimurium to productively infect either cultured mammalian cells or mice. This has significant implications for studies that rely on these systems.