Gut microbiota composition alterations are associated with the onset of diabetes in kidney transplant recipients

Background The gut dysbiosis associated with diabetes acquired before or after kidney transplantation (KT) has not been explored. Methods Patients transplanted at our institution provided fecal samples before, and 3-9 months after KT. Fecal bacterial DNA was extracted and 9 bacteria or bacterial groups were quantified by qPCR. Results 50 patients (19 controls without diabetes, 15 who developed New Onset Diabetes After Transplantation, NODAT, and 16 with type 2 diabetes before KT) were included. Before KT, Lactobacillus sp. tended to be less frequently detected in controls than in those who would become diabetic following KT (NODAT) and in initially diabetic patients (60%, 87.5%, and 100%, respectively, p = 0.08). The relative abundance of Faecalibacterium prausnitzii was 30 times lower in initially diabetic patients than in controls (p = 0.002). The relative abundance of F. prausnitzii of NODAT patients was statistically indistinguishable from controls and from diabetic patients. The relative abundance of Lactobacillus sp. increased following KT in NODAT and in initially diabetic patients (20-fold, p = 0.06, and 25-fold, p = 0.02, respectively). In contrast, the proportion of Akkermansia muciniphila decreased following KT in NODAT and in initially diabetic patients (2,500-fold, p = 0.04, and 50,000-fold, p<0.0001, respectively). The proportion of Lactobacillus and A. muciniphila did not change in controls between before and after the transplantation. Consequently, after KT the relative abundance of Lactobacillus sp. was 25 times higher (p = 0.07) and the relative abundance of A. muciniphila was 2,000 times lower (p = 0.002) in diabetics than in controls. Conclusion An alteration of the gut microbiota composition involving Lactobacillus sp., A. muciniphila and F. prausnitzii is associated with the glycemic status in KT recipients, raising the question of their role in the genesis of NODAT.