In Vitro Synergistic Effect of Psidium guineense (Swartz) in Combination with Antimicrobial Agents against Methicillin-Resistant Staphylococcus aureus Strains
Table 2
Combination testing of the aqueous extract of Psidium guineense with antimicrobial agents against MRSA strains.
Staphylococcus aureus
Combination
Individual MIC (μg/mL)
Combination MIC (μg/mL)
Individual FIC
FIC index (FICI)
Interpretation
% MIC reduced
% reduction of viable cells1
LFBM 01
AE + AMC
250/25
125/0.048
0.5/0.002
0.5
Synergistic
50.0/99.8
80.21
AE + AMP
250/400
125/0.78
0,5/0.002
0.5
Synergistic
50.0/99.8
84.43
AE + CFO
250/400
125/0.78
0.5/0.002
0.5
Synergistic
50.0/99.8
87.04
AE + CIP
250/50
125/0.09
0.5/0.002
0.5
Synergistic
50.0/99.8
93.49
AE + MER
250/25
125/0.048
0.5/0.002
0.5
Synergistic
50.0/99.8
84.24
LFBM 26
AE + AMC
250/50.0
125/0.78
0.5/0.002
0.5
Synergistic
50.0/99.8
88.82
AE + AMP
250/400
125/0.78
0.5/0.002
0.5
Synergistic
50.0/99.8
83.58
AE + CFO
250/400
31.25/0.78
0.125/0.002
0.125
Synergistic
87.5/99.8
80.90
AE + CIP
250/50.0
125/0.09
0.5/0.002
0.5
Synergistic
50.0/99.8
94.59
AE + MER
250/25
125/0.048
0.5/0.002
0.5
Synergistic
50.0/99.8
80.76
LFBM 28
AE + AMC
250/12.5
125/0.024
0.5/0.002
0.5
Synergistic
50.0/99.8
83.38
AE + AMP
250/400
125/0.78
0.5/0.002
0.5
Synergistic
50.0/99.8
89.71
AE + CFO
250/100
125/0.19
0.5/0.002
0.5
Synergistic
50.0/99.8
86.91
AE + CIP
250/50.0
125/0.09
0.5/0.002
0.5
Synergistic
50.0/99.8
94.45
AE + MER
250/25.0
62.5/0.048
0.25/0.002
0.25
Synergistic
75.0/99.8
89.08
LFBM 33
AE + AMC
250/12.5
125/0.024
0.5/0.002
0.5
Synergistic
50.0/99.8
78.89
AE + AMP
250/200
125/0.39
0.5/0.002
0.5
Synergistic
50.0/99.8
76.72
AE + CFO
250/200
62.5/0.39
0.25/0.002
0.25
Synergistic
75.0/99.8
81.53
AE + CIP
250/50.0
62.5/0.78
0.25/0.002
0.25
Synergistic
75.0/99.8
94.09
AE + MER
250/12.5
125/0.024
0.5/0.002
0.5
Synergistic
50.0/99.8
81.84
MIC: minimal inhibitory concentration; FIC: fractional inhibitory concentration; AMC: amoxicillin/clavulanic acid; AMP: ampicillin; CFO: cefoxitin; CIP: ciprofloxacin; MER: meropenem; AE: aqueous extract of P. guineense; LFBM: Laboratório de Fisiologia e Bioquímica de Microorganismos. . 1%reduction of viable cells in wells containing the combination aqueous extract of P. guineense (1/2 MIC) and antimicrobials agents (1/512 MIC).
