Transcriptomic and metabolomic insights into the oxygen adaptation mechanisms of Enterococcus faecalis YN771

Enterococcus faecalis is a facultative anaerobe often associated with persistent infections. It can rapidly adapt and grow in environments with varying oxygen levels (aerobic, microaerobic, hypoxic, and anaerobic), making it a major pathogen responsible for refractory periapical periodontitis. The study investigated the fatty acid content and its variations in Enterococcus faecalis strain YN771 under different oxygen concentrations. Subsequently, transcriptomics and metabolomics were combined to characterize the underlying mechanisms. The results showed that YN771 exhibited altered transcriptional and metabolomic profiles when exposed to different oxygen levels. These changes highlighted the oxygen adaptation and regulatory mechanisms of YN771, including sulfur metabolism, glutathione metabolism, glutamate metabolism, pyruvate metabolism, tricarboxylic acid cycle, peptidoglycan biosynthesis, and fatty acid biosynthesis regulation. Additionally, the study examined the expression changes of virulence factors in YN771 under different oxygen levels, which are also regulated by quorum sensing. This research comprehensively explores the metabolic regulation of YN771 under varying oxygen levels and analyzes key enzyme genes and virulence factors involved in its oxygen response regulation, providing mechanistic insights for developing therapeutic strategies against this notorious pathogen.