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Fig. 2 | BMC Microbiology

Fig. 2

From: Laboratory contamination in airway microbiome studies

Fig. 2

Estimate of contaminant levels in ten-fold dilution series of Salmonella (SDS). The major operational taxonomic units (OTUs) observed in the initial Salmonella sample (10^7 bacteria/mL) were assigned to f__Enterobacteriaceae;g__. Using the NCBI nucleotide BLAST tool we confirmed that these OTUs (OTU821080, OTU813457 and OTU813217) matched to the genus Salmonella. With each successive dilution, the relative abundance of f__Enterobacteriaceae;g__ decreased. By dilution 3 (45 PCR cycles), the percentage had reduced to 47.83%. For comparison, PCR amplification of the 16S rRNA gene was performed at both 30 and 45 cycles for all SDS samples. The control is a sample of PCR water processed through steps of PCR and sequencing alongside the SDS samples. Taxonomic rank is described using prefixes (f__: family, g__: genus)

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