Co-occurrence plots for genera detected in adenoid swabs, middle ear fluid, and nasopharyngeal swabs. Plots are shown for data before (A) and after (B) removal of the signal derived from contaminants. Genera detected in both adenoid and MEF are highlighted. Note that Achromobacter was not removed based upon spurious distribution. However, following the removal of all contaminant OTUs and rarefaction to 400 reads, the sample with Achromobacter at >1.5% relative abundance was removed due to low sequencing depth. The removal based on spurious distribution of a Rhizobium OTU, detected in both NP and MEF, is also shown.