Fig. 3

Alpha and beta diversity of gut microbiome in hospitalized COVID-19 patients. (a) Shannon index, which measures species richness and evenness, indicating lower diversity in the critical group compared to the low group (p = 0.0129) (b) Chao1 richness estimator indicates significantly lower species counts in the critical group compared to the low group (p = 0.0073) and the moderate group (p = 0.0197) (*p < 0.05 and **p < 0.01). (c-e) Beta diversity analysis was performed using Aitchison Principal Coordinates Analysis (PCoA) for Body-mass-index (BMI) categories (< 30 vs. ≥30 kg/m²), showing distinct clustering in the low group (p = 0.034). (f-h) PCoA plots for gender (female vs. male) show distinct clustering in the critical severity group (p = 0.009), suggesting gender-based differences in microbiome composition are more pronounced in this group. (i-k) PCoA plots for age categories (< 60 vs. ≥60 years) show a more distinct clustering in the critical group (p = 0.006), indicating age-related differences in microbiome composition. The statistical significance of these groupings was assessed using permutational multivariate analysis of variance (Permanova) within the vegan R package, with Pr(> F) and R² values confirming the observed differences in microbial community composition. The relative abundance of various gut microbiota showing the top 15 taxa at family level (l) and genus level (m) in hospitalized COVID-19 patients across different severity groups