Insertion site sequencing (InSeq) of Serratia marcescens during bacteremia

Serratia marcescens is a ubiquitous Gram-negative bacterium that causes healthcare-associated opportunistic infections that can be difficult to treat due to multi-drug resistance. In this study, we sought to determine the fitness requirements of S. marcescens during mammalian bloodstream infection by performing transposon insertion sequencing using a murine model of bacteremia. Mice were infected intravenously with a library of random transposon insertion mutants, followed by recovery of bacteria from the spleen and the identification of bacterial fitness genes.