Fig. 1

Patient selection and stool sample collection for gut microbiome analysis. Of an initial 722 ICU admissions screened, 54 patients were enrolled in the current study based on our criteria. For gut microbiome analysis, stool samples were collected from patients after kefir administration; however, 25 of the 54 participants did not have bowel movements during their ICU stay and were unable to provide a stool sample. For the remaining 29 patients, an initial stool sample was collected within 72 h of ICU admission (from all 29 patients), with a subsequent sample gathered after kefir administration (from 13 patients), contingent on bowel activity