Bacterial metabolites influence the autofluorescence of .

is a bacterial pathogen that has been implicated in severe gastrointestinal infections. has intrinsic green autofluorescence and the level of this autofluorescence is known to be increased by growth time and oxygen. Currently, it is unclear if dietary compounds or metabolites from the gut microbiota are able to enhance autofluorescence. Here, we aimed to determine potential factors that affect autofluorescence. After screening a large repertoire of compounds, we identified several substances, like L-lysine and pantothenate, that led to an increased autofluorescence. We also found that several members of the gut microbiota, such as and , can increase autofluorescence through their secreted compounds. We further focused on the effect of on autofluorescence and found that multiple enteric strains of could enhance autofluorescence. We used this enhanced autofluorescence to identify in co-cultures by flow cytometry. Our findings shed light on the relationship between and other members of the gut microbiota, as well as different factors that can affect autofluorescence.