DNA was purified from the mixture using the QIAamp Fast DNA Stool Mini Kit. PCR was performed using the KOD FX Neo, and 1st PCR primers (16S rRNA gene V3-V4 regions). Next, index PCR was performed using the ExTaq HS, and Index primers. The PCR products were quantified using Synergy LX and QuantiFluor dsDNA System. Paired-end sequencing of the PCR products was performed using MiSeq. The sequencing data were analyzed using the QIIME 2 pipeline.