Microbial DNA was isolated from urine samples and PCR that targets the V3V4 region of the 16S rRNA gene was performed. After purification, sequencing libraries were constructed using the Illumina TruSeq Nano DNA LT Library Prep Kit.Enriched library fragments underwent size selection and purification via gel electrophoresis. Each qualified onboard sequencing library was gradient diluted and mixed according to the required ratio, and onboard sequencing was performed. Paired-end amplicon sequencing was performed on the Illumina Nova Seq platform.