Dysbiosis in the upper airway and gut, and altered urine metabolome in Malaysian diabetic patients.

Gut dysbiosis and an increased risk of respiratory infection in type 2 diabetes have been well recognised. However, the relationship between the gut and respiratory pathobiont carriage rates in the type 2 diabetic Malaysian population is understudied. To address the knowledge gap, we profiled the gut and upper respiratory tract (URT) microbial composition, and the urine metabolome of 31 type 2 diabetic adults and 14 non-diabetic adults. We showed a higher prevalence of opportunistic URT pathogens in diabetes patients. A higher abundance of pro-inflammatory bacteria Escherichia coli was detected in the gut of the diabetic subjects. This coincided with the higher levels of sorbitol and taurine in the urine. The former is produced by aldose reductase, an enzyme strongly associated with airway inflammation, while the latter is a substrate for bacterial antioxidants (i.e. H2S). Despite a small sample size, our study revealed the potential relationship between the carriage rates of URT pathobionts with the gut microbial and urine metabolomic profiles of diabetes patients.