Shotgun metagenomic sequencing
Libraries were prepared using Illumina DNA preparation kit (CAT: 20060060). Before tagmentation, a total of 10 ng DNA input was normalized to 30 ml using nuclease-free water. Library quantification was performed using the Qubit assay, and the quality was assessed using the Tapestation 4150 High Sensitivity D1000 Screentape system. Twenty-four barcoded libraries were pooled at equimolar concentrations (4 nM) and spiked with 1% PhiX control. Finally, libraries were sequenced using a Nextseq 550 High Output v2.5 (300 cycles) to generate 149 bp paired-end reads.