Table 2.
MIC of antibiotics and AgNPs synthesized from Nocardiopsis valliformis strain OT1 and synergistic effect of AgNPs combined with antibiotics against bacterial isolates by dilution plate method
| Bacteria | MIC of AgNPs (µg/ml) | MIC of antibiotics (µg/ml) | AgNPsb | Kanamycinb | Ampicillinb | Tetracyclineb | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Kan | Amp | Tet | A | A + AgNPs | A | A + AgNPs | A | A + AgNPs | |||
| Escherichia coli ATCC8739 | 80 ± 0.17 | 1.5 ± 0.5 | 2.0 ± 0.0 | 0.79 ± 0.35 | 61.1 ± 0.05 | 39.62 ± 0.01 | 62.16 ± 0.04 | 73.94 ± 0.06 | 72.61 ± 0.01 | 23.13 ± 0.02 | 61.1 ± 0.05 |
| Klebsiella pneumoniae ATCC700603 | 70 ± 0.07 | 32.0 ± 4.6 | Not founda | 24.0 ± 4.61 | 36.81 ± 0.01 | 28.01 ± 0.23 | 72.61 ± 0.01 | 35.09 ± 0.03 | 78.73 ± 0.05 | 84.52 ± 0.15 | 84.83 ± 0.01 |
| Pseudomonas aeruginosa ATCC10145 | 60 ± 0.04 | 32.0 ± 0.0 | Not founda | 21.3 ± 4.6 | 76.74 ± 0.01 | 33.21 ± 0.04 | 84.83 ± 0.01 | 9.91 ± 0.06 | 76.56 ± 0.01 | 81.66 ± 0.03 | 86.13 ± 0.01 |
| Staphylococcus aureus ATCC6338 | 30 ± 0.11 | 1.16 ± 0.28 | 0.1 ± 0.03 | 0.25 ± 0.0 | 73.82 ± 0.02 | 39.54 ± 0.01 | 75.17 ± 0.09 | 86.68 ± 0.05 | 86.13 ± 0.05 | 44.2 ± 0.03 | 76.5 ± 0.05 |
| Bacillus subtilis PCM2021 | 60 ± 0.14 | 29.3 ± 0.17 | 0.1 ± 0.01 | 0.15 ± 0.08 | 35.85 ± 0.05 | 85.9 ± 0.01 | 86.13 ± 0.01 | 34.62 ± 0.22 | 37.64 ± 0.03 | 17.14 ± 0.04 | 35.85 ± 0.05 |
Bacterial growth inhibition (%)
Mean value is significantly different at p ≤ 0.05
Values expressed in mean ± SD
MIC, minimal inhibitory concentration; Kan, kanamycin; Amp, ampicillin; Tet, tetracycline; A, antibiotic; AgNPs, silver nanoparticles
aFor synergistic studies the highest concentration of antibiotic of Etest stripes was used (256 µg/mL)
bGrowth inhibition (%) in the presence of MICs of AgNPs or/and antibiotic