Synergistic Antibiofilm Efficacy of Thymol and Piperine in Combination with Three Aminoglycoside Antibiotics against Klebsiella pneumoniae Biofilms

Table 2

Minimum biofilm inhibitory concentration (MBIC) of thymol, piperine, aminoglycoside, and fractional inhibitory concentration index (FICI) of combination against K. pneumoniae.

	MBIC (μg/mL)							MBIC reduction fold of antibiotics		FICI/interpretation
	Alone			Combined				(ATB/Thy)^α	(ATB/Pip)^α	(ATB/Thy)^ο	(ATB/Pip)^ο
	ATB	Thy	Pip	(ATB/Thy)	(Thy)	(ATB/Pip)	Pip
Streptomycin
Kp55	8	1024	1024	0.125	128	4	128	64	2	0.14/S	0.63/Ad
Kp02	4	512	1024	0.25	32	4	256	16	1	0.13/S	1.25/I
Kp03	4	512	1024	0.25	64	1	512	16	4	0.19/S	0.75/Ad
Kp04	4	512	1024	0.25	32	2	256	16	2	0.13/S	0.75/Ad
Kp05	8	256	1024	0.125	64	4	512	64	2	0.27/S	1/Ad
Amikacin
Kp55	4	1024	1024	0.25	64	1	256	16	4	0.13/S	0.50/S
Kp02	2	512	1024	0.25	64	1	512	8	2	0.25/S	1/Ad
Kp03	4	512	1024	2	256	4	64	2	1	1/Ad	1.06/I
Kp04	16	512	1024	4	128	16	16	4	1	0.50/S	1.02/I
Kp05	8	256	1024	4	256	8	512	2	1	1.50/I	1.5/I
Kanamycin
Kp55	8	1024	1024	2	32	4	512	4	2	0.28/S	1/Ad
Kp02	4	512	1024	0.25	128	4	16	16	1	0.31/S	1.02/I
Kp03	1	512	1024	1	32	1	128	1	1	1.06/I	1.13/I
Kp04	8	512	1024	0.25	64	2	1024	32	4	0.16/S	1.25/I
Kp05	8	256	1024	2	256	4	32	4	2	1.25/I	0.53/Ad