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The increase in carbapenemase-producing Enterobacterales (CPE), including metallo-β-lactamase (MBL) producers, is a severe global health concern. Thus, highly sensitive and specific methods for detecting MBL producers are needed. In this study, we tested the detectability of MBL-producing Enterobacterales against three types of MBL inhibitors (sodium mercaptoacetate, SMA; ethylenediaminetetraacetic acid, EDTA; and dipicolinic acid, DPA) used in combination with a modified carbapenem inactivation method (mCIM). These inhibitor-combination mCIMs were tested against 129 CPE (IMP, 93; NDM, 11; KPC, 13; NMC, 1; OXA-48, 11) and 75 non-CPE. For evaluation of MBL inhibitors, we used two concentrations for each of the three inhibitors: DPA (200 and 300 mg l− 1), EDTA (5 and 10 mM), and SMA (1500 and 3000 mg l− 1). The overall sensitivities of SMA, EDTA and DPA were 97.1–99.0 %, 81.7–99.0 % and 88.5–96.2 %, respectively. Moreover, each method showed high specificity (99.0–100 %). Although inhibitor-combination mCIMs were highly sensitive and specific for the detection of MBL producers, we found that sensitivity was dependent on the concentration of inhibitors.