Tracking gene expression and oxidative damage of O2-stressed Clostridioides difficile by a multi-omics approach

Clostridioides difficile is the major pathogen causing diarrhea following antibiotic treatment. It is considered to be a strictly anaerobic bacterium, however, previous studies have shown a certain and strain-dependent oxygen tolerance. In this study, the model strain C. difficile 630Δerm was shifted to micro-aerobiosis and was found to stay growing to the same extent as anaerobically growing cells for the duration tested. However, an extensive change in gene expression was determined by RNA-Seq with 49 effected genes after 15 min and more than 400 after one hour. Effected genes exhibit a wide range of functionality, including the metabolism of amino acids, enzymes for cell wall synthesis, the uptake and metabolism of sugars, synthesis of B vitamins as well as purine synthesis and DNA repair. Our study suggests that tolerance of C. difficile towards O2 is based on a complex and far-reaching adjustment of global gene expression.