Antimicrobial Potential of Caffeic Acid against Staphylococcus aureus Clinical Strains
Table 2
Antibacterial potential of caffeic acid (CA) alone and in antibiotic-phytochemical combination against Staphylococcus aureus. The combined effect of CA and antibiotics was evaluated using plates with MHA enriched with the subinhibitory concentration of CA.
C MI (µg/mL)
E+CA
-Δ
D
DA+CA
-Δ%
FO
FOX+CA
-Δ%
V
VA+CA
-Δ%
S. aureus ATCC 25923
256
0.38
0.38
0
0.064
0.047
-27
1
1
0
0.75
0.75
0
S. aureus ATCC 43300
256
256
256
0
256
256
0
12
8
-33
0.38
0.50
-32
S. aureus ATCC 6538
256
0.064
0.125
95
0.023
<0.016
-30
2
1
-50
0.50
0.50
0
S. aureus 1
1024
0.50
0.25
-50
0.064
0.032
-50
2
1.5
-25
0.75
0.50
-33
S. aureus 2
512
0.50
0.38
-24
0.064
0.064
0
0.75
0.75
0
0.38
0.75
97
S. aureus 3
512
256
0.19
<-99.99
0.023
<0.016
-30
1.5
0.38
-75
0.50
0.50
0
S. aureus 4
512
0.38
0.19
-50
0.064
0.047
-27
2
1
-50
0.50
0.50
0
S. aureus 5
512
256
4
-98
0.094
0.064
-32
256
24
-91
0.75
0.50
-33
S. aureus 6
512
0.50
0.125
-75
0.064
<0.016
-75
1.5
1.5
0
0.38
0.50
32
S. aureus 7
256
0.38
0.19
-50
0.032
0.032
0
1
1
0
0.50
0.38
-24
S. aureus 8
1024
0.19
0.19
0
0.032
<0.016
-50
1.5
0.50
-67
0.38
0.38
0
S. aureus 9
512
0.38
0.19
-50
0.064
<0.016
-75
1
1
0
0.38
0.38
0
S. aureus 10
512
32
3
-91
0.047
<0.016
-66
2
0.75
-63
0.38
0.38
0
S. aureus 11
1024
0.38
0.19
-50
0.047
0.032
-32
1.5
0.75
-50
0.38
0.19
-50
S. aureus 12
512
256
256
0
256
256
0
256
256
0
0.75
0.75
0
S. aureus 13
512
256
0.125
<-99.99
256
0.094
<-99.99
32
12
-63
0.75
0.50
-33
S. aureus 14
1024
256
<0.016
<-99.99
256
<0.016
<-99.99
256
<0.016
<-99.99
0.75
<0.016
-98
S. aureus 15
1024
0.25
0.19
-24
0.064
0.023
-64
8
1.5
-81
0.38
0.38
0
S. aureus 16
1024
256
256
0
256
256
0
256
32
-88
0.50
0.50
0
S. aureus 17
512
256
<0.016
<-99.99
256
<0.016
<-99.99
256
<0.016
<-99.99
0.38
<0.016
-96
S. aureus 18
512
0.38
0.094
-75
0.047
<0.016
-66
6
0.75
-88
0.50
0.50
0
S. aureus 19
1024
256
256
0
256
256
0
256
64
-75
0.50
0.50
0
S. aureus 20
256
256
<0.016
<-99.99
256
<0.016
<-99.99
12
<0.016
<-99.99
0.38
<0.016
-96
Median
512
0.5
0.19
-50
0.064
0.032
-32
2
1
-63
0.50
0.5
0
pi
0.0004
0.0003
0.0003
0.091
taphylococcus aureus 1 ÷ 20: strains from intractable surgical wounds. : caffeic acid. : minimum inhibitory concentration. : erythromycin. ICs changes according to the formula [(MIC of antibiotic - MIC of antibiotic with CA) / MIC of antibiotic] x 100%. A: clindamycin. OX: cefoxitin. A: vancomycin. ilcoxon Signed-Rank Test.