HC-enriched vOTUs had a higher frequency of enzymes such as K00986 (RNA-directed DNA polymerase), K01520 (dUTP pyrophosphatase), K01185 (lysozyme), and two enzymes involving assimilatory sulfate reduction (K00390 [phosphoadenosine phosphosulfate reductase] and K00957 [sulfate adenylyltransferase]) compared to CKD-enriched vOTUs. This evidence concerns the gene LYZ and chronic kidney disease.