With great interest, we read the paper by Ammer-Hermenau et al, which features a multicentre microbiome study that included buccal and rectal samples taken at admission from 450 patients with acute pancreatitis.1 Severe acute pancreatitis was post hoc defined as persistent organ failure and/or collections that required drainage. These patients were propensity score matched with patients with mild acute pancreatitis. Remarkedly, over-representation of 10 known short-chain fatty acid (SCFA)-producing bacteria was found in the severe group. The authors conclude that SCFAs might be associated with worse outcomes and speculate that the increased mortality that was observed in the intervention group of the Probiotics in Pancreatitis Trial (PROPATRIA) could be explained by SCFA producers in the probiotics formula.2 There are, however, some limitations to this study, and we believe the author’s statements are in need of nuance.

First, the authors did not include a control group of healthy volunteers. Therefore, it is not possible to conclude from these data that SCFA producers are increased in the severe acute pancreatitis group or decreased in the mild group, compared with healthy subjects.

Second, the authors …