Table 2.

Antibiotic susceptibility testing (AST) of known resistance genes predicted to have previously undescribed activity. As per the Antibiotic Resistance Platform, AMR genes were cloned into the pGDP plasmid series and transformed into wild-type E. coli BW25113, which is representative of a clinical isolate. AST was performed for each construct using the microdilution broth method, with the inoculum prepared using the growth method following CLSI guidelines.

Antibiotic	Resistance gene	Plasmid	MIC (μg ml−1) wild-type E. coli BW25113	CLSI resistant MIC (μg ml−1) breakpoint for Enterobacteriaceae	CLSI resistant MIC (μg ml−1) breakpoint for P. aeruginosa
Ampicillin	None	None	64	≥32	–
	CMY-2	pGDP1	>256	≥32	–
	CTX-M-3	pGDP1	>256	≥32	–
	CTX-M-27	pGDP1	>256	≥32	–
	OXA-1	pGDP1	>256	≥32	–
	TEM-30	pGDP1	>256	≥32	–
Amoxicillin/clavulanic acid	None	None	8–16	≥32/16	–
	CMY-2	pGDP1	256	≥32/16	–
	CTX-M-3	pGDP1	64	≥32/16	–
	CTX-M-15	pGDP1	16	≥32/16	–
	OXA-1	pGDP1	64	≥32/16	–
	TEM-1	pGDP1	128	≥32/16	–
Cefazolin	None	None	4	≥8/≥32 (urine only)	–
	CMY-2	pGDP1	>256	≥8/≥32 (urine only)	–
	CTX-M-3	pGDP1	>256	≥8/≥32 (urine only)	–
	CTX-M-27	pGDP1	>256	≥8/≥32 (urine only)	–
	TEM-1	pGDP1	256	≥8/≥32 (urine only)	–
Cefixime	None	None	0.25	≥4	–
	CMY-2	pGDP1	>256	≥4	–
	CTX-M-3	pGDP1	32	≥4	–
Ceftazidime	None	None	0.5	≥16	≥32
	CMY-2	pGDP1	256	≥16	nr
	CTX-M-3	pGDP1	16–32	≥16	nr
	CTX-M-27	pGDP1	128	≥16	nr
Ertapenem	None	None	0.25	≥2	–
	CTX-M-27	pGDP1	128	≥2	–
Ceftriaxone	None	None	0.25	≥4	–
	CMY-2	pGDP1	128	≥4	–
	CTX-M-3	pGDP1	>256	≥4	–

–, no CLSI breakpoint for P. aeruginosa due to intrinsic resistance; nr, not relevant as CMY-2, CTX-M-3, and CTX-M-27 were only identified in P. aeruginosa.