Boxplots showed the Alpha diversity metrics in the supra-mucosal samples among groups. The comparisons of the Alpha diversity metrics include Shannon (A), Simpson (B), ACE (C), Chao1 (D), sobs (E) and coverage (F). The error bars show the respective minimum and maximum values; the thick line represents the median value; the boxes demarcate the 1st to 3rd quartiles (Q1-Q3), and the abnormal value is shown as ‘o'.