Which of the following describes the role of the Modified Carbapenem Inactivation Method (mCIM) in laboratory diagnostics?
- A Measures the minimum bactericidal concentration of carbapenems
- B Identifies porin loss-mediated carbapenem resistance by EDTA chelation
- C Detects carbapenemase production by showing bacterial inactivation of meropenem on a disk ✓
- D Screens for ESBL by testing cefotaxime-clavulanate synergy
Correct answer: C. Detects carbapenemase production by showing bacterial inactivation of meropenem on a disk
Explanation
The mCIM is a phenotypic test in which the test organism is incubated with a meropenem disk in water; carbapenemase-producing organisms hydrolyse the meropenem in the disk, which is then placed on an E. coli ATCC 25922 lawn. If carbapenemase is present, the disk is inactivated and the E. coli grows up to the disk edge (zone ≤15 mm = positive). A paired eCIM (adding EDTA) distinguishes MBLs (EDTA restores activity, larger zone) from serine carbapenemases. It detects all major carbapenemase classes (KPC, MBL, OXA-48 type).
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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