Gut Microbiome Profiles Are Associated With Type 2 Diabetes in Urban Africans

Gut dysbiosis has been associated with several disease outcomes including diabetes in human populations. Currently, there are no studies of the gut microbiome composition in relation to type 2 diabetes (T2D) in Africans. Here, we describe the profile of the gut microbiome in nondiabetic adults and investigate the association between gut microbiota and T2D in urban West Africans. Gut microbiota composition was determined in 291 Nigerians (98 T2D, 193 non-T2D controls) using fecal 16S V4 rRNA gene sequencing done on the Illumina MiSeq platform. Data analysis of operational taxonomic units (OTU) was conducted to describe microbiome composition and identify differences between T2D and controls. The most abundant phyla were Firmicutes, Actinobacteria, and Bacteroidetes. Clostridiaceae and Peptostreptococcaceaea were significantly lower in T2D cases than controls (p<0.001). Feature selection analysis identified a panel of 18 OTUs enriched in T2D that included Desulfovibrio piger, Prevotella, Peptostreptococcus, and Eubacterium. A panel of 17 OTUs that was enriched in the controls included Collinsella, Ruminococcus lactaris, Anaerostipes and Clostridium. OTUs with strainlevel annotation showing the largest fold-change included Cellulosilyticum ruminicola (log2FC= -3.1; p=4.2 x10 -5 ), Clostridium paraputrificum (log2FC= -2.5; p=0.005), and Clostridium butyricum (log2FC=-1.76; p=0.01), all lower in T2D cases. These findings are notable because supplementation with Clostridium butyricum and Desulfovibrio piger has been shown to improve hyperglycemia and reduce insulin resistance in murine models. This first investigation of gut microbiome and diabetes in urban Africans shows that T2D is associated with compositional changes in gut microbiota highlighting the possibility of developing strategies to improve glucose control by modifying bacterial composition in the gut.