design: Genomic DNA was isolated employing the Qiagen QIAamp Fast DNA Stool Mini Kit (cat. no.51604, Qiagen) following a modified protocol (14) and stored at 80C until further analyses. The second aliquot was crosslinked with 1% formaldehyde for 20 minutes (15). DNA and crosslinked samples were sent to Phase Genomics for ProxiMeta full-service analysis. The shotgun library was prepared using the Watchmaker DNA Library Prep Kit (cat. no. 7K0103-096, Watchmaker Genomics, USA), and the proximity ligation library was created using the ProxiMeta Hi-C kit (cat. no. KT5045, Phase Genomics, USA). Shotgun metagenomic and Hi-C libraries were sequenced on an Illumina NovaSeqX platform (2  150 bp paired-end reads).