Fig. 4

Distribution of the 20 most abundant operational taxonomic units (OTUs) observed in negative control samples (NCS). The NCS were dominated by OTU 759061 assigned to the family Enterobacteriaceae (20.93%), OTU 4389128 assigned to a genus within the class ML635J-21 (16.31%), OTU 437105 and New. Reference OTU 133 both assigned to the genus Ralstonia (8.30 and 5.45%, respectively). Taxonomic rank is described using prefixes (c__: class, o__: order, f__: family, g__: genus). Data presented as the average relative abundance. Data unrarefied