DNA isolation and 16S rRNA gene sequencing
Feces from participants and donors were collected at the hospital or home according to the collection instructions and delivered immediately on dry ice. Specifically, each donor provided stool samples for 6 weeks for FMT capsule manufacturing, and fecal samples from donors were collected at weeks 0, 3, and 6. Meanwhile, fecal samples of patients from both groups were collected at baseline and weeks 4 and 12 during follow-up. In total, 0.18–0.22 g stool samples were used to extract total bacterial genomic DNA following the protocol of the DNA extraction kit (#DP328, Tiangen Company, Beijing, China). The concentration and purity of the extracted bacterial DNA were detected using the Qubit 2.0 Fluorometer (Thermo Scientific, USA). The 16S rRNA gene of the V4 region-specific primers was 515F GTGCCAGCMGCCGCGGTAA and 806 R GGACTACHVGGGTWTCTAAT. Sequencing libraries were generated using an Illumina TruSeq DNA PCR-Free Library Preparation Kit (Illumina, USA) following the manufacturer’s recommendations, and index codes were added. The library was sequenced on an Illumina HiSeq platform, and 250 bp paired-end reads were generated (Novogene, China). The mean of Raw PE reads is 91,819.Microbiome bioinformatics was performed with the QIIME2 software package (Quantitative Insights Into Microbial Ecology)11.