AUTHOR=Ticer Taylor D. , Tingler Anna M. , Glover Janiece S. , Dooley Sarah A. , Kendrick Jacob , Zackular Joseph P. , Devkota Suzanne , Wu Gary D. , Mahalak Karley , Engevik Amy , Engevik Melinda A. 

TITLE=Bacterial metabolites influence the autofluorescence of Clostridioides difficile

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1459795

DOI=10.3389/fmicb.2024.1459795

ISSN=1664-302X

ABSTRACT=<p><italic>Clostridioides difficile</italic> is a bacterial pathogen that has been implicated in severe gastrointestinal infections. <italic>C. difficile</italic> 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 <italic>C. difficile</italic> autofluorescence. Here, we aimed to determine potential factors that affect <italic>C. difficile</italic> autofluorescence. After screening a large repertoire of compounds, we identified several substances, like L-lysine and pantothenate, that led to an increased <italic>C. difficile</italic> autofluorescence. We also found that several members of the gut microbiota, such as <italic>Enterococcus faecalis, Klebsiella aerogenes</italic> and <italic>K. pneumoniae</italic>, can increase <italic>C. difficile</italic> autofluorescence through their secreted compounds. We further focused on the effect of <italic>K. pneumoniae</italic> on <italic>C. difficile</italic> autofluorescence and found that multiple enteric strains of <italic>K. pneumoniae</italic> could enhance <italic>C. difficile’s</italic> autofluorescence. We used this enhanced autofluorescence to identify <italic>C. difficile</italic> in <italic>K. pneumoniae</italic> co-cultures by flow cytometry. Our findings shed light on the relationship between <italic>C. difficile</italic> and other members of the gut microbiota, as well as different factors that can affect <italic>C. difficile</italic> autofluorescence.</p>