Identification of circulating microbial DNA and its association with kidney function in patients with diabetic kidney disease.

Aim: Recently, substantial studies have been accumulated to indicate the important role of gut microbiota in diabetic kidney disease (DKD). The abnormal change of bacterial-derived products could imply specific injuries or play beneficial or harmful roles in DKD progression. In this study, we examined the presence and contribution of the Klebsiella oxytoca gene in the circulation of patients with DKD.

Method: We enrolled a total of 16 healthy participants, 17 patients with DKD, 5 patients with DKD requiring haemodialysis (HD), and 7 patients with CKD without diabetes. Bacterial-derived DNA (16S rDNA and a specific K. oxytoca gene) in the blood was detected using droplet digital PCR, then investigated the relationship with clinical characteristics.

Results: We identified an increase in K. oxytoca genes in the blood of DKD patients. Interestingly, blood K. oxytoca copies and K. oxytoca/ 16S DNA ratio correlated with higher blood creatinine and BUN levels together with lower eGFR in DKD patients. K. oxytoca levels were also associated with higher neutrophil percentage, lower lymphocyte frequency, and increased neutrophil-to-lymphocyte ratio.

Conclusion: Collectively, the presence of the K. oxytoca gene in the circulation could serve as a biomarker reflecting reduced renal function in DKD patients.