Characterization of the gut microbiota in frail elderly patients

Background The change in the composition of gut microbiota has been reported in the elderly and in the frail individuals; however, studies on gut microbiota in frail elderly are limited. Aims This study aimed to investigate the gut microbiota of the frail elderly. Methods From September 2017 to February 2018, 27 elderly patients hospitalized in the Department of Geriatrics of our hospital were enrolled and divided into the frailty group (n = 15) and the control group (n = 12) based on the cutoff of 0.25 for the frailty index. The fecal samples were collected for 16S rRNA-amplicon sequencing to analyze the composition and richness of gut microbiota. Operational taxonomic unit (OTU) clustering was performed using Usearch software. Intra-sample diversity (alpha-diversity) analysis and inter-sample diversity (beta-diversity) analyses were performed. The community richness was compared between the two groups at family and genus levels. Results There were 1903 and 1880 OTUs identified in the control and frailty groups, respectively, with 1282 OTUs overlap between the two groups. The alpha diversity of microbiota community was similar between the two groups, whereas the frailty group had larger beta diversity than the control group. The top-10 taxonomy categories and abundances of gut microbiota between the two groups were similar. As for the gut microbiota composition, 4 families and 17 genera were significantly different between the two groups (p < 0.05). Conclusion These results suggested that frailty can affect gut microbiota diversity and compositions in late elderly hospitalized patients.