title: biofilm
design: All the sequences were aligned to a SILVA bacterial reference (https://www.arb-silva.de/) (Quast et al. 2012), and the chimeric sequences were identified and removed using a chimera.vsearch command. The taxonomy of 16S rRNA sequences were assigned using the Ribosomal Database Project (RDP) classifier (Wang et al. 2007) based on SILVA 16S rRNA database (SSU123).