Fig. 4.

Chronic alcohol use is associated with increases in the relative read counts of genus-agglomerated OTUs classified to Gram-negative organisms. The number of sequencing reads of OTUs that map to known Gram-negative genera was significantly increased in AUD populations compared with controls in the gargle (A), brush (B), and BAL samples (C). Boxplot whiskers 95% confidence interval of the mean ± SE number of Gram-negative OTUs in the different sites for AUD and healthy controls; *P < 0.05 for healthy controls vs. AUD cohorts (AUD, n = 41; control, n = 37). D: differentially abundant, genus-agglomerated Gram-negative OTUs in each biogeographical site in AUD subjects over healthy controls.