Mucus
PCR amplification was done using Platinum SuperFi II DNA Polymerase (Thermo Fisher Scientific, Waltham, MA, USA), with the 341F (5'-CCTACGGGNGGCWGCAG-3')-785R (5'-GACTACHVGGGTATCTAATCC-3') primer pair. Amplicon analysis was done using Illumina platform MiSeq paired-end reads sequencing (2 x 250 bp) (MiSeq Reagent Kit v2).