The Mechanism Underlying the Antibacterial Activity of Shikonin against Methicillin-Resistant Staphylococcus aureus

Table 2

Antibacterial activity of shikonin (SKN), ampicillin, and oxacillin against eight S. aureus strains.

Bacterial strains	Class	mec A gene	β-lactamase activity	MIC (μg/mL)
				SKN	Ampicillin	Oxacillin
ATCC 33591	MRSA	+	+	15.6	125	>250
ATCC 25923	MSSA	−	−	7.8	0.9	1.9
Clinical isolates
KWMrI 1039^a	MRSA	+	+	7.8	31.2	>250
KWMrI 1040	MRSA	+	−	15.6	31.2	>250
KWMrI 1041	MRSA	+	+	15.6	62.5	>250
KWMrI 1046	MRSA	+	+	31.2	250	>250
KWMrI 1047	MRSA	+	+	7.8	125	>250
KWMrI 1048	MRSA	+	−	31.2	62.5	>250

MSSA, methicillin-susceptible S. aureus; MRSA, methicillin-resistant S. aureus; KWMrI (a), MRSA strains from the Department of Plastic Surgery, Wonkwang University Hospital.