Figure 1.

The imbalance of the gut microbiota, or dysbiosis, in IBDs: a role for oxygen? Dysbiosis is observed in patients suffering from IBDs. Repeated observations indicate a decrease in obligate anaerobes (F. prausnitzii), an increase of facultative anaerobes (Enterobacteriaceae) and even the appearance of aerobes. Superimposed with the normal anaerobic gut physiology of the distal intestine, these observations support the hypothesis of a shift in bacterial communities caused by an increase of oxygen that changes the Eh in the gastrointestinal tract.