Table 2. Broth Microdilution AST Results for ADC Variants in pBCSK(−) E. coli DH10B in This Study^a.

β-lactamase	CAZ	CAZ + MB076	CTX	CTX + MB076	TOL	TOL + MB076	FDC	FDC + MB076	FEP
ADC-7	64	4	64	1	8	1	0.5	0.5	0.25
ADC-30	128	2	64	2	8	0.5	0.5	0.5	0.25
ADC-33	2048	16	128	1	256	16	2	0.5	0.5
ADC-162	128	4	64	2	16	1	0.5	0.25	0.25
ADC-212	512	64	128	16	256	16	1	0.5	0.5
ADC-219	256	16	16	2	128	8	1	0.5	0.12

^aMICs in mg/L. Antimicrobial susceptibility tests were interpreted according to 2021 CLSI criteria for Enterobacterales: for ceftazidime (CAZ) and cefiderocol (FDC), MIC ≤ 4 mg/L is susceptible (S), MIC = 8 mg/L is intermediate (I), and MIC ≥ 16 mg/L is resistant (R); for cefotaxime (CTX) MIC ≤ 1 mg/L is S, MIC = 2 mg/L is I, and MIC ≥ 4 mg/L is R; for ceftolozane (TOL), no CLSI breakpoints have been defined. Most isolates were highly susceptible to cefepime (FEP, ≤0.25 mg/L, S) and were therefore not tested with MB076. MB076 was used at a fixed concentration of 10 mg/L.