Table 3.
Antibiotic resistance modulatory activity of leaves extract of R. heudelotii
| Antibioticsa | Extracts concentrationb | Bacteria, MIC (μg/mL) and modulating factors (in bracket) | Modulating effect (%)b | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| E. coli | E. aerogenes | K. pneumoniae | P. stuartuii | P. aeruginosa | |||||||
| AG100 | AG102 | AG100Tet | CM64 | EA289 | EA298 | K24 | NEA16 | PA124 | |||
| AMP | 0 | - | - | - | - | - | - | - | - | - | |
| MIC/2 | - | - | - | - | - | - | - | - | - | 0 | |
| MIC/4 | - | - | - | - | - | - | - | - | - | 0 | |
| CHL | 0 | 8 | 32 | 64 | 256 | 128 | 64 | 64 | 64 | 64 | |
| MIC/2 | 8 (1) | 16 (2) | 32 (2) | 256 (1) | 128 (1) | 32 (2) | 32 (2) | 32 (2) | 32 (2) | 66.67 | |
| MIC/4 | 8 (1) | 16 (2) | 64 (1) | 256 (1) | 256 (0.5) | 64 (1) | 64 (1) | 32 (2) | 32 (2) | 33.33 | |
| CIP | 0 | ≤0.5 | ≤0.5 | 128 | 64 | 128 | 1 | 128 | 1 | 32 | |
| MIC/2 | ≤0.5 (na) | ≤0.5 (na) | 64(2) | 32 (2) | 128 (1) | 1 (1) | 64 (2) | 1 (1) | 32 (1) | 33.33 | |
| MIC/4 | ≤0.5 (na) | ≤0.5 (na) | 128(1) | 64 (1) | 128 (1) | 1 (1) | 64 (2) | 1 (1) | 32 (1) | 11.11 | |
| KAN | 0 | 64 | 4 | 8 | 2 | 16 | 32 | 4 | 16 | 128 | |
| MIC/2 | 4 (16) | 1 (4) | 2 (4) | 1 (2) | 4 (4) | 32 (1) | 2 (2) | 8 (2) | 64 (2) | 88.89 | |
| MIC/4 | 16 (4) | 4 (1) | 2 (4) | 2 (1) | 8 (2) | 32 (1) | 2 (2) | 8 (2) | 64 (2) | 66.67 | |
| ERY | 0 | 32 | 64 | - | - | 64 | 16 | 128 | 16 | 128 | |
| MIC/2 | 32 (1) | 64 (1) | - | - | 64 (1) | 16 (1) | 128 (1) | 8 (2) | 64 (2) | 22.22 | |
| MIC/4 | 32 (1) | 64 (1) | - | - | 64 (1) | 16 (1) | 128 (1) | 8 (2) | 128 (1) | 11.11 | |
| TET | 0 | 2 | 8 | 32 | 16 | 32 | 4 | 16 | 4 | 16 | |
| MIC/2 | ≤0.5 (≥4) | 4 (2) | 4 (8) | 4 (4) | 4 (8) | 2 (2) | 8 (2) | 2 (2) | 16 (1) | 88.89 | |
| MIC/4 | ≤0.5 (≥4) | 4 (2) | 8 (4) | 16 (1) | 8 (4) | 2 (2) | 8 (2) | 2 (2) | 16 (1) | 77.78 | |
a: TET tetracycline, KAN kanamycin, ERY erythromycin, CHL chloramphenicol, CIP ciprofloxacin, AMP ampicillin;; −: MIC not detected at up to 256 μg/mL; (): Modulating factor; na: not applicable,
b: MIC Minimal Inhibitory Concentration. c: Percentage of antibiotic’s modulating effect by the plant extracts. Values in bold represent modulating factor ≥ 2 and modulating effect observed on more than 70% of the tested MDR bacteria