However, data regarding the use of MER-VAB, IMI-REL, CFD and CAZ-AVI-ATM for the treatment of infections due to bacteria with difficult-to-treat resistance (DTR) are scarce in real-life settings (Falcone et al., 2021; Meschiari et al., 2021; Rebold et al., 2021; Falcone et al., 2022). This evidence concerns the gene ATM and infection.