title: metagenomics of COVID-19 patients;]: gut microbiota
design: Fecal samples were collected before any therapeutic treatment (such as antibiotics) after hospitalization and froze immediately with liquid nitrogen and stored in -80  condition before DNA extraction. Fecal DNA was extracted according to the manufactures instruction of the QIAamp Fast DNA Stool Mini Kit (Qiagen, German). Approximately 200 mg of stool sample was used for DNA extraction. 500 ng DNA of each sample was used for library construction. The DNA libraries were prepared according to the manufactures instruction of the KAPA Hyper Prep Kit. In brief, microbiome DNA was fragmented and tagged with adapters in one step and then added with index sequences during the PCR ampli_cation. Libraries that passed the quality control analysis, including the Agilent 4200 analysis and quantifications, were used for sequencing. Libraries were sequenced on the NovaSeq 6000 platform (Illumina) using the 150 bp paired-end strategy. Reads aligned to the human genome were removed, and the clean reads were uploaded to the SRA.