Fig. 4

Relative abundance distribution of TPM-normalized antibiotic resistance gene (ARG) counts in European and African samples by ARG class. For visualization, zero read counts were excluded, and values were log10-transformed. Each data point is represented by a circle, colored by continent. In all boxplots, the center line indicates the median; the box bounds represent the 25th and 75th percentiles. Whiskers extend to 1.5 times the interquartile range. Statistical comparisons between continents (Europe vs. Africa) are indicated by brackets, with significance levels denoted as follows: ns (not significant), * (p < 0.05). Group comparisons were performed using a two-sided, unpaired exact Wilcoxon-Mann-Whitney test. Statistical valid comparisons were only done when both groups (Europe and Africa) contained each at least 5 observations (data points). The exact p-values for the aminoglycosides, amphenicols, β-lactams, folate pathway antagonists, lincosamides, macrolides and other, and tetracyclines boxplots are 0.62, 0.27, 0.96, 0.01, 0.25, 0.02, and 0.03, respectively.