Diversity
In order to determine if within-sample diversity (α-diversity) of each group differed, we calculated the Shannon and Simpson diversity indices (which takes into account both evenness and richness of communities) of the samples from survivors and controls. Evaluation of the bacterial microbiome demonstrated reduced alpha diversity (p<0.05) utilizing both Shannon and Simpson indices (Figure 2a).Bray-Curtis dissimilarity index was used to determine differences in bacterial taxonomic composition between the case and control groups (β-diversity). β-diversity comparisons (Figure 2b) between specimens from both groups showed modest differential clustering (R2=0.26, p=0.006).