Dr. Francisco Guarner, researcher from the Physiology and Pathophysiology of the Digestive Tract group at Vall d’Hebron Institute of Research (VHIR), has participated in the design of a new method that has identified new bacteria in the human microbiome, which were uncharacterized until this study. Furthermore, 8 of these bacteria could be used as preliminary markers of patients with ulcerative colitis. The results of the study have been published in Nature Methods. The reference method for the bacterial taxonomy based in the sequencing of the 16S rRNA gene is biased, since several species remain undetected. Specifically, researchers estimate that only detected the 57% and 42% of the species abundance and richness, respectively.For developing the new method, researchers used 40 genes defined as “markers”, which have no mobility (since they are not horizontally transmitted) and only have a single copy in the genome, so can be used to characterize bacterial species in a sample. This method “provides far more resolution because we have detected species that were not classified yet, which in many cases represent more than half of the species which are present in a sample”, Dr. Guarner reports. A total of 252 human faecal samples were analyzed from patients with ulcerative colitis at Vall d’Hebron University Hospital, and from several biobanks from Denmark and the United States. Researchers identified 8 new bacteria which were not present or not abundant in patients with ulcerative colitis, whereas only 3 markers had been found since this study. According to Dr. Guarner, this finding “opens the door to further research of these bacteria in order to identify which role play in ulcerative colitis disorder”.