TABLE 6.

MBL detection techniques

TechniqueTestSubstrate-inhibitor combinationAdvantagesDisadvantagesReference
Clinical microbiologyDisk approximationCeftazidime and 2-mercaptoproprionic acidEasy to useDisk and distance of disk placement not standardized and not always easy to interpret6
Disk diffusionImipenem and EDTAEasy to use and relatively easy to interpretDisk not standardized. MBL-producing bacteria can be imipenem sensitive202
Microdilution testImipenem and EDTA and 1,10-phenanthrolineBased on reduction in MICs, easy to interpretSpecialized and labor intensive, MBL-producing bacteria can be imipenem sensitive99
EtestImipenem and EDTAEasy to use and relatively easy to interpretMBL-producing bacteria can be imipenem sensitive and borderline cases may be missed177
Carbapenem hydrolysisMeropenem and EDTAVery sensitive and deemed to be the gold standardHighly specialized, labor intensive, and interpretation not straightforward180
Molecular detectionPCR for genes for IMP, VIM, etc.Easy to perform, specific for gene familyRequires tailor-made DNA primers, cannot differentiate between variants, may not detect new variants158
DNA probesSpecialized, labor intensiveProbe required for each gene family, cannot differentiate between variants
Cloning and sequencingMolecular gold standardLabor intensive, intepretation of data requires experience167