Sequences with a minimum length of 300 base pairs after primer sequence removal, correct barcode sequences, a maximum of 1 incorrect base pair in the primer sequences, and compliance with the default quality criteria for homopolymers and quality scores in the Quantitative Insights into Microbial Ecology (QIIME) [36] software package (version 1.8.0) were retained for analysis. Any sequence beyond the reversed primer were removed. Sequences beginning with the reverse primer were reverse complemented. Sequences were then clustered into operational taxonomic units (OTUs) at a sequence similarity of 97% in the 16S rRNA chimera-checked Greengene database (dated May 2013) [37] using USEARCH [38]. OTUs with a single sequence were removed. One representative sequence per remaining OTU was taxonomically assigned as a named or unnamed cultivable species or uncultivable phylotype at ≥98.5% identity using HOMD 16S rRNA RefSeq, version 12.0 (http://www.homd.org) [28].