Table 4. Susceptibilities of C. jejuni 11168 and its efflux mutants to phenolic compounds in the absence and presence of PAβN (20 µg/mL)^a, NMP (100 µg/mL)^a, verapamil (100 µg/mL), reserpine (100 µg/mL) or CCCP (0.25 µg/mL)^b.

Phenolic acid orcompound ±inhibitor	11168		11168B		11168F		11168R
	MIC (µg/mL)	Fold diff.	MIC (µg/mL)	Fold diff.	MIC (µg/mL)	Fold diff.	MIC (µg/mL)	Fold diff.
EGCG	78		78		78		313
+PAβN	9.8	8	19.5	4	19.5	4	9.8	32
+NMP	78	1	19.5	4	19.5	4	9.8	256
+Verapamil	78	1	78.5	1	78	1	78	4
+Reserpine	78	1	78.5	1	78	1	78	4
+CCCP	19.5	4	156	0.5	9.8	8	19.5	16
Rosmarinic	156		1.2		313		313
+PAβN	39	4	0.3	4	156	2	78	4
+NMP	39	4	1.2	1	78	4	156	2
+Verapamil	156	1	0.6	2	156	2	313	1
+Reserpine	156	1	0.6	2	78	4	313	1
+CCCP	19.5	8	0.6	2	39	8	156	2
Carnosic	19.5		19.5		39		78
+PAβN	<0.6	>32	0.3	64	2.4	16	<0.6	>128
+NMP	4.9	4	2.4	8	39	1	39	2
+Verapamil	9.8	2	9.8	2	39	1	78	1
+Reserpine	9.8	2	19.5	1	39	1	78	1
+CCCP	4.9	4	19.5	1	39	1	78	1
Chlorogenic	313		4.9		313		313
+PAβN	2.4	128	0.3	16	313	1	39	8
+NMP	625	0.5	2.4	2	625	0.5	78	4
+Verapamil	625	0.5	9.8	0.5	313	1	313	1
+Reserpine	625	0.5	4.9	1	625	0.5	625	0.5
+CCCP	78	4	1.2	4	156	2	156	2
Gallic	313		4.9		78		78
+PAβN	<9.8	>32	0.3	16	19.5	4	<9.8	>8
+NMP	19.5	16	0.3	16	39	2	39	2
+Verapamil	78	4	4.9	1	39	2	78	1
+Reserpine	156	2	4.9	1	39	2	78	1
+CCCP	78	4	<0.3	>16	78	1	78	1
Sinapinic	313		78		156		156
+PAβN	<9.8	>32	<1.2	>64	39	4	<9.8	>16
+NMP	<9.8	>32	<1.2	>64	78	2	156	1
+Verapamil	39	8	156	1	78	2	156	1
+Reserpine	19.5	16	78	1	78	2	156	1
+CCCP	78	4	<1.2	>64	156	1	156	1
Vanillic	313		39		313		156
+PAβN	<0.6	>512	9.8	4	156	2	9.8	16
+NMP	4.9	64	2.4	16	156	2	78	2
+Verapamil	78	4	39	1	313	1	156	1
+Reserpine	156	2	19.5	2	313	1	156	1
+CCCP	156	2	19.5	2	313	1	156	1
Syringic	313		78		156		156
+PAβN	156	2	<1.2	>64	19.5	8	<9.8	>16
+NMP	156	2	<1.2	>64	39	4	39	4
+Verapamil	313	1	39	2	78	2	156	1
+Reserpine	313	1	78	1	78	2	156	1
+CCCP	19.5	16	<1.2	>64	9.8	16	156	1
Ferulic	313		78		156		156
+PAβN	<9.8	>32	<1.2	>64	39	4	<9.8	>16
+NMP	78	4	2.4	32	39	4	39	4
+Verapamil	156	2	78	1	313	0.5	156	1
+Reserpine	313	1	39	2	313	0.5	156	1
+CCCP	313	1	<1.2	>64	<9.8	>16	156	1

“Fold diff.” indicates fold difference, which is calculated using the formula: MIC without an EPI/MIC with an EPI. ≥4-fold changes are indicated in bold.

^aPAβN and NMP significantly (p<0.05) reduced the MICs of the phenolic compounds in 11168, 11168B, 11168F, and 11168R.

^bCCCP significantly reduced the MICs of the phenolic compounds in 11168, 11168B and 11168F (p<0.05), but not in 11168R (p > 0.05).