Static Immersion and Injection Methods for Live Cell Imaging of Foodborne Pathogen Infections in Zebrafish Larvae

: Important features of host-pathogen interactions have been discovered using nonmammalian hosts. Therefore, model organisms such as the nematode Caenorhabditis elegans, the social amoeba Dictyostelium discoideum, and zebrafish ( Danio rerio ) have been increasingly used for studying bacterial pathogenesis in vivo. These host models are amenable for live cell imaging studies, which can also benefit from online resources and databases ( Dictybase.org , ZFIN.org , Wormbase.org ), as well as from a wide repertoire of genetic and genomic tools generated over the years by the scientific community. Here, we present the protocols we developed to study bacterial dynamics within infected embryonic zebrafish. This chapter describes detailed methods to achieve infections of zebrafish larvae with the foodborne pathogen Salmonella enterica serovar Typhimurium, including embryonic zebrafish spawning and maintenance, bacterial inoculation through intravenous injections and static immersion, followed by fluorescence imaging of infected transgenic zebrafish. Methods for studying bacterial dynamics within zebrafish larvae through live cell imaging are also described.