PPIB and clostridium difficile infection: Among β-lactam resistance genes (Supplementary Table S4), blaCTX-M and blaTEM showed significant differences (0.73 vs. 51.76 and 1.44 vs. 59.50 RPKM for healthy individuals vs. CDI patients; p < 0.0001 for each Student’s t test; Supplementary Tables S2 and S3).