Synergistic Interaction between Boesenbergia rotunda (L.) Mansf. Essential Oil and Cloxacillin on Methicillin-Resistant Staphylococcus aureus (MRSA) Inhibition

Table 3

Fraction inhibitory concentration (FIC) index of cloxacillin (CLX) plus B. rotunda essential oil (BREO) against S. aureus strains.

Bacterial strains	MIC(a)		MIC(c)		FIC		FICI
	BREO (mg/mL)	CLX (µg/mL)	BREO (mg/mL)	CLX (µg/mL)	BREO	CLX
MRSA DMST 20649	4^ND	512^R	1^ND	16^R	0.25	0.03	0.28
MRSA DMST 20651	4^ND	512^R	1^ND	16^R	0.25	0.03	0.28
MRSA DMST 20652	4^ND	512^R	1^ND	32^R	0.25	0.06	0.31

Synergistic interaction (FIC index ≤0.5). FICI = FIC index; MIC(a) = MIC value of chemical alone; MIC(c) = MIC value of chemical in combined drug. ^RResistant; ^Ssusceptible; ^NDno data available.