Table 2.
Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against bacteria by serial dilution plate count assay.
| Bacteria | MIC (µg/mL) | MBC (µg/mL) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S1 | S2 | S3 | S4 | S5 | GENT | S1 | S2 | S3 | S4 | S5 | GENT | |
| E. coli O157:H7 | 1–4 | 2–4 | 2–4 | 4–16 | 8–16 | 0.5 | 2–4 | 2–8 | 2–8 | 8–32 | 16–32 | 1 |
| S. aureus ATCC 25923 | 8–16 | 32 | 16–32 | 16–64 | 32–100 | 1–2 | 16–32 | 32 | 32–64 | 100 | 100 | 2 |
| * MIC 407 | 2–16 | 4–32 | 16–32 | 32–64 | 32–100 | 32 | 16 | 4–32 | 16–32 | 32–64 | 32–100 | 32 |
| * MIC 408 | 4–16 | 4–32 | 8–64 | 32–64 | 64–100 | 2–4 | 4–16 | 4–32 | 16–64 | 32–100 | 64–100 | 2–4 |
| * MIC 411 | 2–16 | 4–32 | 16–100 | 32–64 | 32–100 | 16–32 | 4–32 | 8–32 | 32–100 | 32–100 | 64–100 | 16–32 |
| MIC 504 | 2–4 | 4–16 | 16–32 | 16–32 | 32–64 | 0.5 | 2–8 | 4–16 | 32 | 32–64 | 64 | 1–4 |
| MIC 509 | 2–4 | 4–16 | 4–32 | 16–64 | 32–64 | 0.25 | 4–8 | 8–16 | 16–32 | 16–64 | 32 | 0.5 |
| Range of MIC/MBC | 1–16 | 2–32 | 2–100 | 4–64 | 8–100 | 0.25–32 | 2–32 | 2–32 | 2–100 | 8–100 | 16–100 | 0.5–32 |
The MIC value corresponds to the lowest concentration that inhibits ≥ 90% of bacterial growth. The MBC value corresponds to the lowest concentration that inhibits 100% of bacterial growth. Experiments were performed in triplicate of three independent experiments for each cell type. The five isolates of S. pseudintermedius are MIC 407, 408, 411, 504 and 509. * Methicillin-resistant Staphylococcus pseudintermedius (MRSP); S1–S5 = AgNPs, GENT = Gentamicin antibiotic.