Table 1.

Details of the mcr-1 positive E. coli isolates from swine.

Isolates	Age group	PFGE pattern	MIC of colistin (mg/L)	Other resistance phenotypec	Genetic environment	Replicon	Conjugation frequency	Plasmid size (kb)	Other resistance gene (s)
SHP50	50 days	F	4	FFC, TET, CIP, SXT	IncI2-mcr-1-IncI2	IncI2	4 × 10−4	~60	oqxAB, floR
SHP52	50 days	G	4	AMP, FFC, NEO, TET, CIP	IncX4-mcr-1-IncX4	IncX4	1.27 × 10−3	~33	oqxAB, floR
SHP49, SHP36	50 days	E	8	AMP, FFC, GEN, NEO, CIP, SXT	IncX4-mcr-1-IncX4	IncX4	2 × 10−5, 1.78 × 10−4	~33	oqxAB, floR
SHP47	50 days	P	8	AMP, CTX, FFC, FOS, GEN, NEO, SXT	ISApI1-mcr-1-IncHI2	IncHI2 (ST3)	2 × 10−6	~244	blaCTX−M−14, floR, fosA3, oqxAB
SHP48	50 days	Q	8	NEO, FFC, SXT, TET, CIP	ISApI1-mcr-1- IncHI2	IncHI2 (ST3)	–	~275	oqxAB, floR
SHP39	50 days	N	4	AMP, CTX, FFC, FOS, GEN, NEO, TET, SXT	ISApI1-mcr-1-IncHI2	IncHI2 (ST3)	2 × 10−6	~244	blaCTX−M−14, floR, fosA3, oqxAB
SHP41	50 days	O	4	AMP, CTX, FFC, FOS, TET, SXT	ISApI1-mcr-1- ISApI1, IncX4-mcr-1-IncX4	IncHI2 (ST3), IncX4	–	~238, ~33	blaCTX−M−15, floR, fosA3, oqxAB
SHP51	50 days	R	8	AMP, CTX, FFC, FOS, GEN, NEO, TET, SXT	ISApI1-mcr-1-IncHI2, ISApI1-mcr-1- ISApI1	IncHI2 (ST3)	2.90 × 10−5	~244, chromosome	blaCTX−M−14, floR, fosA3
SHP43	50 days	D3	8	AMP, CTX, FFC, FOS, GEN, NEO, CIP, SXT	ISApI1-mcr-1-IncHI2	IncY-IncHI2	–	~350	blaCTX−M−14, floR, fosA3, oqxAB
SHP45	50 days	D2	8	AMP, CTX, FFC, FOS, GEN, NEO, TET, CIP, SXT	ISApI1-mcr-1-IncI2, ISApI1-mcr-1-IncHI2	IncI2, IncHI2 (ST3)	–	~64, ~244	blaCTX−M−14, floR, fosA3, oqxAB
SHP26	70 days	D1	8	AMP, CTX, FFC, FOS, GEN, NEO, TET, CIP, SXT	ISApI1-mcr-1-IncHI2	IncHI2 (ST3)	6.84 × 10−5	~244	blaCTX−M−14, floR, fosA3, oqxAB
SHP46a	50 days	K2	4	AMP, FFC, NEO, SXT	ISApI1-mcr-1-?	ND	–	~104	oqxAB, floR
SHP22	70 days	K1	8	AMP, FFC, NEO, SXT	ISApI1-mcr-1- ISApI1	F29:A-:B-	–	~78	floR
SHP17	70 days	J	4	AMP, CTX, FFC, NEO, TET, SXT	unknown	IncY	8.64 × 10−6	~83	blaCTX−M−55, oqxAB, floR
SHP28	70 days	J	8	AMP, CTX, FFC, NEO, TET, SXT	IncX4-mcr-1-IncX4	IncX4	–	~33	oqxAB, floR
SHP31a	70 days	L	8	FFC, NEO, TET, CIP, SXT	ISApI1-mcr-1- ISApI1	ND	–	~80	oqxAB, floR
SHP24	70 days	L	8	FFC, NEO, TET, SXT	ISApI1-mcr-1- ISApI1	F53:A-:B-	–	~80	floR
SHP33a	70 days	M	16	FFC, NEO, TET, CIP, SXT	unknown	NA	–	chromosome	oqxAB, floR
SHP23	70 days	smeared	8	AMP, FFC, NEO, TET, CIP, SXT	IncX4-mcr-1-IncX4	IncX4	5.43 × 10−5	~33	oqxAB, floR
SHP32	70 days	A	4	AMP, FFC, TET, CIP, SXT	IncX4-mcr-1-IncX4	IncX4	–	~33	oqxAB, floR
SHP14b	4 months	A	8	AMP, FFC, GEN, TET, CIP, SXT	IncX4-mcr-1-IncX4	IncX4	–	~33	oqxAB, floR
SHP16	4 months	I	8	TET, SXT	ISApI1-mcr-1-IncI2	IncI2	8.12 × 10−5	~64	oqxAB
SHP10	4 months	H	8	AMP, FFC, NEO, TET, SXT	IncX4-mcr-1-IncX4	IncX4	5 × 10−6	~33	oqxAB, floR
SHP8	4 months	C	8	AMP, FFC, NEO, TET, SXT	ISApI1-mcr-1-IncI2	IncI2	–	~62	oqxAB, floR
SHP7	4 months	B	4	AMP, CTX, FOX, FFC, TET, SXT	IncX4-mcr-1-IncX4, ISApI1-mcr-1-IncI2	IncX4, IncI2	–	~33, ~62	oqxAB, floR, blaCMY−2
SHP59	5 months	S	4	AMP, FFC, TET, SXT	IncX4-mcr-1-IncX4	IncX4	–	~33	oqxAB, floR

^aIsolates failed to get transconjugants.

^bIsolates successfully get transformant by the electroporation.

^cAMP, ampicillin; CIP, ciprofloxacin; CTX, cefotaxime; FFC, florfenicol; FOS, fosfomycin; GEN, gentamicin; NEO, neomycin; SXT, sulfamethoxazole-trimethoprim; TET, tetracycline. Patterns transferred by conjugation are underlined.