Classification of Streptococcus OTUs in background, supraglottic, and BAL microbiota. Twenty-one Streptococcus OTUs were aligned to the Greengenes database of 16S rRNA sequences. In each case, the top hit (>96%) was used for final classification. Perfect match was indicated (*) if found. (A) Background samples contained predominantly Streptococcus thermophilus. (B) Supraglottic samples contained predominantly Streptococcus mitis. (C) Relative abundances of all Streptococcus OTUs in all 29 BAL samples clustered as indicated in Figure 3 (never-smokers indicated with green label and smokers with blue label). PneumotypeUN is enriched with Streptococcus thermophilus while PneumotypeSCT has higher relative abundances of Streptococcus mitis.