Table 3.
Mean zone of inhibition (mm) and antimicrobial activity (MIC values in μg/mL) of Ma-AgNPs and antibiotics against multidrug and non-multidrug-resistant bacteria. The mean and standard deviation (SD) reported for each microbial strain at different concentrations were based on three biological replicates.
| Bacterial Strain | Zone of Inhibition (mm) | MIC (µg/mL) | |||||
|---|---|---|---|---|---|---|---|
| Ma-AgNPs EA |
Ma-AgNPs EB |
Ma-AgNPs EC |
Antibiotic | Ma Extract |
AgNO3 | ||
| B. cereus | 20.7 ± 0.5 | 19.7 ± 0.5 | 19.0 ± 0.0 | 14.3 ± 4.0 a | NA | NA | 2.5 |
| S. enterica ATCC 14028 | 19.7 ± 2.1 | 18.0 ± 5.0 | 17.3 ± 6.1 | 12.0 ± 1.7 b | NA | NA | 1.3 |
| E. coli ATCC 25922 | 20.7 ± 5.8 | 20.0 ± 4.0 | 15.3 ± 2.0 | 15.1 ± 3.0 b | NA | NA | 1.3 |
| S. aureus ATCC 25923 | 31.3 ± 4.5 | 26.3 ± 3.2 | 25.9 ± 0.5 | 25.7 ± 2.5 b | NA | NA | 1.3 |
| E. faecalis ATCC 29212 | 35.0 ± 4.2 | 22.5 ± 1.0 | 19.5 ± 1.0 | 13.0 ± 4.2 b | NA | NA | 5.0 |
| P. aeruginosa ATCC 27853 | 25.7 ± 5.1 | 22.3 ± 3.5 | 21.0 ± 3.6 | 13.3 ± 3.2 c | NA | NA | 5.0 |
| K. pneumoniae * | 15.5 ± 1.0 | 12.0 ± 1.0 | 12.0 ± 1.0 | 15.0 ± 1.0 d | NA | NA | 5.0 |
| E. coli * | 11.7 ± 1.0 | 11.0 ± 1.0 | 12.0 ± 1.0 | 10.7 ± 1.0 d | NA | NA | 5.0 |
| P. aeruginosa * | 18.7 ± 0.5 | 17.3 ± 1.5 | 16.3 ± 0.5 | 12.7 ± 2.0 d | NA | NA | 10.0 |
* Multidrug-resistant bacteria; EA = Ma-AgNPs at 400 µg/mL; EB = Ma-AgNPS at 200 µg/mL; EC = Ma-AgNPs at 100 µg/mL. Antibiotics: a = chloramphenicol; b = carbenicillin; c = tetracycline; d = nourseothricin. NA = non-active at the tested concentrations.