Fig. 4

Heatmap and differential abundance of specific gut microbiota taxa in hospitalized COVID-19 patients across different severity groups. (a) Heatmap of the centered-log transformed abundance of significantly altered taxa showing intra-group variation among patients with the same COVID-19 severity, highlighting distinct microbial profiles associated with each group. The color intensity represents the transformed abundance, with darker shades of red indicating higher abundance. (b) Comparison between low and moderate-severity groups reveals significant increases in taxa such as Desulfonispora thiosulfatigenes and Streptococcus vestibularis in moderate group. It decreases in taxa such as Streptococcus periodonticum, Phocaeicola plebius, and Clostridium perfringens in moderate group. (c) Comparison between low and critical severity groups shows significant increases in taxa such as Klebsiella pneumoniae, Prevotella loeschii, and Breznakia pachnodae with corresponding decreases in Ruminiclostridium cellulolyticum, Streptococcus periodonticum, and Suterella wadsworthensis in critical group; identified using ANCOMBC2. The analysis revealed differentially abundant species with statistical significance levels indicated as *q < 0.05, **q < 0.01, and ***q < 0.001