Synergism and the mechanism of action of the combination of α-mangostin isolated from Garcinia mangostana L. and oxacillin against an oxacillin-resistant Staphylococcus saprophyticus

Table 3 Minimum inhibitory concentration (MIC) of oxacillin, α-mangostin, and nisin alone and in combination

Strains	MIC (μg/ml)			FIC (μg/ml)	FIC index
Strains	OXA	AMT	NIS	OXA + AMT	OXA + AMT
S. saprophyticus DMST 27055	128 ^R	8	256	16 + 2	0.37 ^SI
S. saprophyticus DMST 27058	128 ^R	8	256	16 + 2	0.37 ^SI
S. saprophyticus DMST 4236	128 ^R	8	256	16 + 2	0.37 ^SI
S. saprophyticus DMST 4672	128 ^R	8	256	16 + 2	0.37 ^SI
S. saprophyticus DMST 5057	128 ^R	8	256	16 + 2	0.37 ^SI
S. saprophyticus DMST 8034	128 ^R	8	256	16 + 2	0.37 ^SI
S. aureus ATCC 29213^P	0.5 ^S	4	1	N/D	N/D

S. aureus ATCC 29213 ^P, was used as a positive control
^S Susceptible, ^R Resistant, ^SI Synergistic interaction, N/D Not determine
OXA Oxacillin, AMT α-mangostin, NIS Nisin
The MICs are presented as the median values measured from three independent experiments; each experiment was performed in triplicate

ISSN: 1471-2180