title: 16S rRNA sequencing of introitus sample
design: Sample was collected by obstetrician using eSwab Liquid Amies Collection and Transport System (Copan Diagnostics, USA).  A swab from neonatal ear-skin was collected by neonatologist (eSwab Liquid Amies Collection and Transport System, Copan Diagnostics). The neonatal stool samples were collected from a diaper in the second or third day postpartum. The material was stored at -80C, before further processing. The genomic DNA was extracted using the ZymoBiomics DNA Miniprep Kit (Zymo Research, USA) following the manufacturers instructions. The V3-V4 region of the 16S rRNA gene was amplified by PCR and sequenced on the MiSeq platform (Illumina, USA) at Department of Medical Genetics at Medical University of Warsaw, using the 2250 bp paired-end read protocol.