Table 5.

The effect of the efflux pump inhibitors PaβN and CCCP on biocide susceptibility in chlorhexidine-adapted strains and their respective wild-types. Numbers highlighted in bold indicate a ≥fourfold change in MIC relative to no EPI (alone)

	CHD			CET			CPC			HDPCM
	Alone	+PaβN	+CCCP	Alone	+PaβN	+CCCP	Alone	+PaβN	+CCCP	Alone	+PaβN	+CCCP
6	8–16	8–16	1	0.0007	≤0.0003	0.0007	4	4	16	4	2	4
6 CHD	64	64	2	0.007	≤0.0003	0.015	32	4	64	64	4	64
CFI_080_KPC2	4–8	8–16	1	0.0007	≤0.0003	0.007	8	2	32	16	2	32
CFI_080_KPC2 CHD	16	16	2	0.007	≤0.0003	0.015	32	2	64	16	2	64
MKP103	128	128	1	0.007	≤0.0003	0.015	32	4	64	16	4	64
	CTAB			CHL			CIP
	Alone	+PaβN	+CCCP	Alone	+PaβN	+CCCP	Alone	+PaβN	+CCCP
6	8	2	32	8	2	16	0.25	≤0.06	0.125
6 CHD	32	8	64	64	8	32	0.25	0.125	0.25
CFI_080_KPC2	16	4	32	8	2	16	≤0.06	≤0.06	≤0.06
CFI_080_KPC2 CHD	64	4	128	16	4	16	≤0.06	≤0.06	≤0.06
MKP103	32	8	128	128	8	64	>64	>64	>64

Antimicrobials tested included chlorhexidine digluconate (CHD), (%), cetrimide (CET), cetylpyridinium chloride (CPC), hexadecylpyridinium chloride monohydrate (HDPCM), cetyltrimethylammonium bromide (CTAB), chloramphenicol (CHL and ciprofloxacin (CIP). All values in mg l⁻¹ except for CET whose values represent % of active ingredient.