Open AccessEvaluation of inhibitor-combination mCIM for detecting MBL-producing Enterobacterales using three MBL inhibitors
Author(s) -
Kageto Yamada,
Masakazu Sasaki,
Waka Imai,
Hiroatsu Murakami,
Toshisuke Morita,
Kotaro Aoki,
Yoshikazu Ishii,
Kazuhiro Tateda
Publication year - 2019
Publication title -
journal of medical microbiology/journal of medical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 117
eISSN - 1473-5644
pISSN - 0022-2615
DOI - 10.1099/jmm.0.001073
Subject(s) - dipicolinic acid , ethylenediaminetetraacetic acid , chemistry , microbiology and biotechnology , biology , chelation , organic chemistry , spore
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.