design: Genomic DNA from the stool samples was extracted using a ZymoBIOMICS DNA Miniprep Kit (Zymo Research, USA), according to the manufacturers protocol. The quality and quantity of the DNA samples were evaluated by Implen NanoPhotometr N60 UV-Vis spectrophotometry (Implen NanoPhotometer, USA).  V3 and V4 hypervariable regions of the bacterial 16S rRNA gene were amplified using 515F and 806R primers. Libraries were prepared with Nextera XT Index Kit followed by sequencing using MiSeq System.