The V3-V4 region of 16S rRNA genetically specific fragments was amplified with primers 338F (5-ACTCCTACGGGA-GGCAGCAG-3) and 806R (5-GGACTACHVGGGTWTCTAAT-3). The PCRs were conducted with 4 L 5 TransStart FastPfu buffer, 2 L of 2.5 mM deoxynucleoside triphosphates (dNTPs), 0.8 L each primer (5 M), 0.4 L TransStart FastPfu DNA Polymerase, 10 ng of DNA, and dH20 to a volume of 20 L. A negative control was prepared using the same volume of dH20 instead of DNA. The PCR conditions included 27 cycles of 30 seconds at 95C, 30 seconds at 55C, and 45 seconds at 72C. Subsequently, we confirmed the size of the amplicons through agarose gel electrophoresis. Amplicons were then subjected to paired-end sequencing on the Illumina MiSeq PE300 sequencing platform at Majorbio Bio-Pharm Technology Co. Ltd. (Shanghai, China).