TABLE 2.

In vitro susceptibilities of diarrhea-causing and gut beneficial bacteria to ciprofloxacin and sanguinarine alone and in combination

Bacterium	MICa of:		CIP results by the MIC SNG of:b
	CIP	SNG	256		128		64		32		16		8		4		2		1		0.5		0.25		0.125
			MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI	MIC	FICI
Beneficial bacteria
B. adolescentis	4	4							0.063	8.016	0.063	4.016	0.063	2.016	0.063	1.016	4	1.5	4	1.25	4	1.125	4	1.063
B. animalis subsp. lactis	8	13.333							0.125	2.416	0.125	1.216	8.042	1.605	16	2.300	16	2.15	16	2.075	16	2.038	10.67	1.352
B. breve	5.333	8							0.125	4.023	0.125	2.023	1.417	1.266	1.417	0.766	5.333	1.25	5.333	1.125	5.333	1.063	5.333	1.031
L. casei	2	16							0.063	2.031	0.063	1.031	2.333	1.667	4	2.25	4	2.125	4	2.063	4	2.031	4	2.016
L. rhamnosus	3.333	32							0.063	1.019	2	1.100	2.667	1.050	2.667	0.925	2.667	0.863	2.667	0.831	2.667	0.816	3.333	1.008
Diarrheal bacteria
E. faecalis	0.5	26.667							0.016	1.231	0.016	0.631	0.016	0.331	0.016	0.181	0.094	0.263	0.125	0.287	0.125	0.269	0.063	0.134
S. flexneri	0.016	16							0.002	2.125	0.002	1.125	0.002	0.625	0.008	0.750	0.008	0.625	0.008	0.563	0.008	0.531	0.004	0.266
V. parahaemolyticus	0.125	32							0.004	1.032	0.004	0.532	0.007	0.306	0.042	0.461	0.063	0.567	0.083	0.695	0.104	0.848	0.125	1.008
L. monocytogenes	1.667	8									0.016	2.009	0.016	1.009	0.016	0.509	0.016	0.259	0.339	0.328	0.833	0.562	0.833	0.531	1	0.616
B. cereus	0.25	64	0.016	4.063	0.016	2.063	0.016	1.063	0.063	0.75	0.063	0.5	0.063	0.375	0.063	0.313	0.042	0.198

^aMIC, MIC of ciprofloxacin (CIP) and sanguinarine (SNG) expressed as an average from three independent experiments, with each performed in triplicate. Units for all MICs are μg/mL.

^bFICI, fractional inhibitory concentration index; FICI values of ≤0.5 indicate synergistic effects, FICI values of >0.5–4 indicate no interaction effect, and FICI values >4 indicate an antagonistic effect.