p-Cresol and C. difficile: A Love-Hate Story Revealed by Raman Spectroscopy

Clostridioides difficile is known to produce p-cresol, a phenolic compound with selective antimicrobial properties, which may contribute to its competitive advantage within the gut microbiome. In this study, we investigated the interaction between Clostrioides difficile and Escherichia coli in coculture to assess the role of p-cresol in modulating interspecies dynamics. Raman spectroscopy was employed as a label-free, nondestructive analytical technique to profile the molecular signatures of both species in mono- and coculture. Excitation wavelengths at 244 and 532 nm were used to enhance complementary vibrational features, including those associated with aromatic compounds like p-cresol. Our results demonstrate distinct spectral changes in coculture conditions suggesting the involvement of p-cresol and its impact on the biochemical composition of E. coli. This dual-wavelength Raman approach offers a powerful means of characterizing microbial interactions and identifying metabolic markers that may drive microbial competition and survival.