Fig. 3

Gut microbiota composition in VAP patients compared to healthy controls. (A) Box plot showing differences in gut microbial α-diversity, measured by the Shannon index, between VAP patients and healthy controls. (B) PCoA plot illustrating the distribution of gut microbiota composition based on β-diversity using weighted UniFrac distances. (C) ANOSIM analysis indicating distinct separation in gut microbiota composition between VAP patients and healthy controls (R = 0.778, p < 0.001). (D) Stacked bar plot of the average relative abundance of bacterial phyla in fecal samples from VAP patients and healthy controls. (E) Box plot comparing the relative abundance (%) of Enterococcaceae and Bacteroidaceae between the two groups. (F) Stacked bar plot depicting the relative abundance (%) of the top 20 bacterial genera in VAP patients and healthy controls. (G) Cladogram from LEfSe analysis highlighting microbial taxa enriched in VAP patients (green nodes) and healthy controls (red nodes). Yellow nodes represent taxa with no significant differences between groups. (H) Venn diagram of pathogenic species in fecal samples, showing 47 species in VAP patients, 39 species in healthy controls, and 25 species shared between the groups. (I) Box plot comparing the relative abundance (%) of pathogenic bacteria in the gut between VAP patients and healthy controls. (J) Heatmap of significantly different pathogenic bacteria between VAP patients and healthy controls across individual samples. Statistical analysis was performed using an unpaired two-tailed Student’s t test. Data are presented as mean ± SD. ** p < 0.01, *** p < 0.001