6308
Universal primers (forward: 341F, reverse: 806R) targeting the V3 to V4 region of the 16S rRNA genes were used for PCR amplification of bacterial DNA. Fifty ng was used for each initial PCR reaction.  Controls without added DNA were run as negative controls. AMPure beads were used for purification of amplicons. Libraries (100 ng of PCR product) were pooled, gel-purified, and quantified using quantitative PCR (qPCR)