Phosphotransferase systems (2.16-fold increase in CDI+ individuals), two-component systems (1.43-fold increase in CDI+ individuals), flagellar assembly (2.52-fold increase in CDI+ individuals), ABC transporters, and bacterial chemotaxis were the top five level 3 gene pathway biomarkers of CDI+ status within the metagenome data set. The gene discussed is ABCG2; the disease is clostridium difficile infection.