The most commonly prescribed antibiotics in the A+B+ CDI group were extended-spectrum cephalosporins (ESCs) (56.4%) followed by fluoroquinolones (45.5%) and beta-lactam/beta-lactamase inhibitors (35.6%), while in the A-B+ group they were fluoroquinolones (66.7%), clindamycin (52.4%) or ESCs (52.4%). The gene discussed is LACTB; the disease is clostridium difficile infection.