DNA Extraction and metagenomic sequencing
To compare our results with the study performed by (Bendia, Signori, et al., 2018), we used the same dataset and DNA extractions as a template for the metagenomics. Due to low DNA mass even after several concentration efforts, extracted DNA was subjected to multiple displacement amplification (MDA) using the illustra GenomiPhi V2 DNA amplification kit (GE Healthcare, Piscataway, NJ, USA), following the manufacturer’s instructions. Three amplification reactions per sample were pooled to obtain sufficient DNA for sequencing. DNA was then purified using AMPure XP beads kit (Beckman Coulter) following the manufacturer’s instructions. Library constructions and shotgun metagenomic sequencing were conducted at “Laboratório Central de Tecnologias de Alto Desempenho em Ciências da Vida” (LaCTAD), Universidade Estadual de Campinas State (UNICAMP), on the Illumina Hiseq 2000 platform using 2x100 bp paired-end system.