design: 16S rRNA gene was amplified using 341F and 805R primers, targeting V3-V4 varible regions and 2X KAPA hot-start ready mix. The amplification condition included an initial denaturation step 3 min at 94 C, followed by 25 cycles of 98 C for 20 s, 55 C for 30 s, and 72 C for 30 s, followed by a single step final extension step at 72 C for 5 min.  Subsequently, 16S amplicon were purified using AMPure XP beads and indexed using 5 l of each Nextera XT index primer in a 50 l PCR reaction, followed by 8-10 cycles of PCR condition above. The final PCR products were cleaned, pooled and diluted to final loading concentration at 6 pM. Cluster generation and 250-bp paired-end read sequencing were performed on an Illumina MiSeq at Omics Sciences and Bioinformatics Center (Chulalongkorn University, Bangkok, Thailand).