Table 4.

Synergy outcomes of fosfomycin-amikacin combination using the Checkerboard assay.

	Genotype/MLST	Fosfomycin MIC (mg/L)			Amikacin MIC (mg/L)
Isolate		Alone	Combined	Fold Decline	Alone	Combined	Fold Decline	FICI/ Interpretation
Kp 1	OXA-232/ST-231 aac(6′)-Ib aadA2	128	64	2	>1024	≤16	≥128	0.50/S
Kp 2	OXA-232/ST-231 aac(6′)-Ib aadA2	32	16	2	>1024	≤8	≥256	0.50/S
Kp 3	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	16	128	-	>4/AN
Kp 4	ST-231 NDM-1 aac(6′)-Ib aadA2	64	32	2	16	128	-	>4/AN
Kp 5	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	>1024	≤8	≥256	0.50/S
Kp 6	OXA-232/ ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp 7	OXA-232/ ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp 8	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp 9	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp10	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp 11	ST-231 NDM-1 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp 12	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤4	≥256	0.50/S
Kp 13	ST-395 aac(3)-lId aac(6′)-Ib	64	32	2	16	64	-	>4/AN
Kp 14	ST-395 aac(3)-IId, aac(6′)-Ib aadA2	64	32	2	8	32	-	>4/AN
Kp 15	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤8	≥128	0.50/S
Kp 16	OXA-232 NDM-5/ST147, armA, aadA1,2,rmtB	64	32	2	1024	≤8	≥128	0.50/S
Kp 17	OXA-232/ST-231 aac(6′)-Ib aadA2	64	32	2	1024	≤8	≥128	0.50/S
Kp 18	ST 395 aac(6′)-Ib	64	32	2	8	64	-	>4/AN

Abbreviation: FICI = fractional inhibition concentration index, Kp = K. pneumoniae, MIC = minimal inhibition concentration, S = synergy, AN = antagonism.