design: DNA was isolated from human stool using DNeasy Blood and Tissue Kit (QIAGEN) following a tissue homogenisation step using Precellys Lysing Kit tubes containing 1.4 mm ceramic beads. DNA was quantitated using Nanodrop 2000 (Thermo Scientific). The V3-V4 hypervariable region of the 16S rRNA gene was PCR amplified for sequencing and sequenced on a MiSeq sequencer (Australian Genome Research Facility (AGRF), Brisbane, Australia).