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Table 2 Susceptibility of reference Staphylococcus aureus strains to combinations of α-amyrin, betulinic acid and betulinaldehyde, and antibiotics vancomycin and methicillin

From: Synergistic antimicrobial activity between pentacyclic triterpenoids and antibiotics against Staphylococcus aureus strains

COMPOUND

ATCC 43300

ATCC 29213

a

b

* MIC a

* MIC b

** FIC a

** FIC b

δ FIC S

* MIC a

* MIC b

** FIC a

** FIC b

δ FIC S

AM

BA

8

8

0.13

0.13

0.26

8

8

0.13

0.13

0.26

AM

BE

-

-

-

-

-

-

-

-

-

-

AM

ME

1

1

0.02

0.06

0.08

1

0.5

0.02

0.25

0.27

AM

VA

1

0.5

0.02

0.25

0.27

8

0.5

0.13

0.25

0.38

BA

BE

-

-

-

-

-

-

-

-

-

-

BA

ME

0.25

4

0

0.25

0.25

0.25

1

0

0.5

0.5

BA

VA

0.25

2

0

0.5

0.5

1

1

0.01

0.5

0.51

BE

ME

-

-

-

-

-

0.25

0.25

0

0.13

0.13

BE

VA

0.5

2

0

0.5

0.5

2

1

0

0.5

0.5

  1. δ AM = α-amyrin, BA = betulinic acid, BE = betulinaldehyde, ME = methicillin, VA = vancomycin; * = minimum inhibitory concentration for combination of two or three compounds expressed in μg/ml as mean of three replicates; ** = fractional inhibitory concentration of individual compounds; δ = the sum of fractional inhibitory concentration of two compounds in the combination, - = no significant effect on inhibition of growth with the concentrations tested