Figure 3. Macrolide resistance and bile-salt hydrolase abundance in relation to time since the last macrolide course.

The dashed lines show the model fit (linear or polynomial), R² indicates the variation explained by the model and the P values (estimated using linear models) are indicated. (a) Macrolide resistance potential inferred from metagenomic analysis, N=14. (b) Bile-salt hydrolase abundance in metagenomes, N=14. (c) Macrolide resistance measured as proportion of anaerobic c.f.u.'s growing with erythromycin compared with c.f.u. without erythromycin, N=80. (d) Combined relative abundance of three bile-salt hydrolase genes (bsh) based on qPCR as a function of time since last macrolide course, N=37.