Working with C. difficile in a Hypoxic Chamber

Clostridioides difficile is an enteropathogen responsible for diarrhea under conditions leading to a dysbiosis of the gut microbiota, in particular after an antibiotic treatment. It is a spore-forming obligate anaerobe, which is, as such, usually cultivated in anaerobiosis in laboratories. Yet the gastrointestinal tract (GIT), its natural niche, is not completely deprived of oxygen (O₂) and the O₂ tension in the gut even rises under conditions of dysbiosis. C. difficile is able to tolerate the low O₂ tensions it encounters in the GIT. C. difficile spores germinate in the small intestine at 4% O₂ and the bacteria are found close to epithelial cells where the O₂ tension is between 1% and 2% O₂. To understand how this anaerobe deals with the oxidative stress found in its environment and to investigate its physiology in atmospheric conditions closer to the O₂ exposure encountered in the GIT, experiments can now be performed in hypoxia chambers in which the O₂ tensions can be modulated. This chapter details how to investigate C. difficile biology in hypoxia.