Table 3.

eCIM and phenotypic ceftazidime-avibactam antimicrobial susceptibility testing with and without zinc addition of nine MBL-producing MDR-GN.

				Semi-automated AST system		Broth microdilution
Strain no.	Organism	MBL	eCIM	Zinc addition (mM)	Phenotypic resistance detected	Zinc addition (mM)	Phenotypic resistance detected
KR29	E. cloacae complex	VIM-1	+	0	No	0	Yes
				0.0682	Yes
700.18	E. coli	NDM-5	+	0	No	0	Yes
				0.0682–0.2274	No
2.10	E. coli	NDM-1	+	0	No	0	Yes
				0.0682	Yes
64.08	M. morganii	VIM-4	+	0	No	0	No
				0.1137	Yes	0.1137	Yes
52.15	P. mirabilis	VIM-1	+	0	No	0	No
				0.1706	Yes	0.0682–0.2274	No*
						0.1706 and 0.2274	Yes**
613.16	P. aeruginosa	VIM-2	+	0	No	0	No
				0.0682	Yes	0.0682	Yes
AV6	P. aeruginosa	VIM-2	+	0	No	0	No
				0.0682	Yes	0.0682	Yes
AV7	P. aeruginosa	VIM-2	+	0	No	0	No
				0.0682	Yes	0.0682	Yes
WE10	P. aeruginosa	VIM-2	+	0	No	0	No
				0.1706	Yes	0.0682	Yes

eCIM, EDTA-modified carbapenemase inactivation method; MDR-GN, multi-drug resistant Gram-negative bacteria; AST, antimicrobial susceptibility testing; no., number; MBL, metallo-β-lactamase; VIM, Verona Integron Metallo-β-lactamase; NDM, New Delhi Metallo-β-lactamase; 0.0682 mM = 4.46 mg/L; 0.2274 mM = 14.87 mg/L; 0.1137 mM = 7.44 mg/L; 0.1706 mM = 11.15 mg/L.

^*With BMD medium.

^**With SAT medium.