Table 2.
Fold reduction in MIC and FIC index of selected antibiotics in combination with VAuNPs, vanillin and CSAuNPs treated XDR PA11 and PA14.
| Fold change in the minimum inhibitory concentration of antibiotics | ||||||
|---|---|---|---|---|---|---|
| Antibiotics | XDR Pseudomonas aeruginosa clinical isolates |
|||||
| PA11 |
PA14 |
|||||
| CSAuNPs | Vanillin | VAuNPs | CSAuNPs | Vanillin | VAuNPs | |
| Chloramphenicol | 1.2 | 2.3 | 3.5 | 1.11 | 2.6 | 3.33 |
| Levofloxacin | 1 | 2 | 2.5 | 1 | 5 | 5 |
| Ciprofloxacin | 1 | 2.5 | 2.5 | 1 | 2.66 | 3.2 |
| Tigecycline | 1 | 2 | 4 | 1.2 | 3.7 | 5 |
| Meropenem | 1.11 | 6.6 | 10 | 1 | 1 | 1 |
| Trimethoprim | 1.16 | 4.6 | 14 | 1.33 | 3 | 4.8 |
| Fosfomycin |
1 |
1.2 |
1.2 |
1 |
1 |
1 |
| Fractional inhibitory concentration index for synergetic activity | ||||||
| Antibiotics | PA11 |
PA14 |
||||
| CSAuNPs |
Vanillin |
VAuNPs |
CSAuNPs |
Vanillin |
VAuNPs |
|
| Chloramphenicol | 0.88 | 0.43 | 0.38 | 0.93 | 0.45 | 0.34 |
| Levofloxacin | 1.03 | 0.48 | 0.44 | 1.03 | 0.24 | 0.24 |
| Ciprofloxacin | 1.03 | 0.44 | 0.44 | 1.03 | 0.41 | 0.35 |
| Tigecycline | 1.03 | 0.43 | 0.29 | 0.86 | 0.29 | 0.24 |
| Meropenem | 0.93 | 0.18 | 0.11 | 1.03 | 1.03 | 1.03 |
| Trimethoprim | 0.89 | 0.25 | 0.11 | 0.78 | 0.36 | 0.25 |
| Fosfomycin | 1.03 | 0.83 | 0.83 | 1.03 | 1.03 | 1.03 |
Fold reduction – Highlighted values indicates the difference between VAuNPs and vanillin.
FICA = MIC of CA in combination/MIC of CA, FICB = MIC of CB in combination/MIC of CB; where A and B are antibiotics and VAuNPs/vanillin/CSAuNPs respectively. FIC index value indicates synergistic (≤0.5), additive (0.5 ≥ 1) and antagonistic (>1) effects of the combinations used.