Microbial DNA was extracted from stool using the Qiagen QIAamp PowerFecal Pro DNA Kit (Cat. No. 51804, Qiagen, Hilden, Germany) following the manufacturer protocol. Extracted DNA was shipped on ice to the Environmental Sample Preparation and Sequencing Facility at Argonne National Laboratory, Biosciences Division (Lemont, IL) for preparation for 16S rRNA gene sequencing. The provided DNA was used for amplification of the V4 region of the 16S rRNA gene using the 515F-806R primers. Resulting amplicon libraries were sequenced on the Illumina MiSeq platform to generate 151-base pair forward and reverse reads.