V3V4-Seq of biofilm loc. 1a
16S rRNA universal primers 341F and 805R (extended by specific Illumina adapter overhang sequences) were used for amplification of the V3/V4 region. Sequencing libraries were labeled with multiplex indexing barcodes using the Nextera XT Index Kit (Illumina, San Diego, USA) following manufacturers recommendations. Quantity and quality of the libraries were assessed with the PicoGreen dsDNA quantification assay (Thermo Scientific, Waltham, USA). The v3 reagent kit was applied for sequencing (Illumina, San Diego, USA).