Table 3. Susceptibilities of C. jejuni 11168 and its efflux mutants to pure phenolic compounds and phenolic extracts of plant origin.
| Antimicrobial | 11168 | 11168B* | 11168F | 11168R | |||||
| MIC (µg/mL) | MIC (µg/mL) | Fold diff. | MIC (µg/mL) | Fold diff. | MIC (µg/mL) | Fold diff. | |||
| Phenolic compounds | |||||||||
| EGCG | 78 | 78 | 1 | 78 | 1 | 313 | 0.25 | ||
| Rosmarinic | 156 | 1.2 | 128 | 313 | 0.5 | 313 | 0.5 | ||
| Carnosic | 19.5 | 19.5 | 1 | 39 | 0.5 | 78 | 0.25 | ||
| Chlorogenic | 313 | 4.9 | 64 | 313 | 1 | 313 | 1 | ||
| Gallic | 313 | 4.9 | 64 | 78 | 4 | 78 | 4 | ||
| Sinapinic | 313 | 78 | 4 | 156 | 2 | 156 | 2 | ||
| Vanillic | 313 | 39 | 8 | 313 | 1 | 156 | 2 | ||
| Syringic | 313 | 78 | 4 | 156 | 2 | 156 | 2 | ||
| Ferulic | 313 | 78 | 4 | 156 | 2 | 156 | 2 | ||
| Rosemary extracts | |||||||||
| I18 | 313 | 19.5 | 16 | 625 | 0.50 | 156 | 2 | ||
| V40 | 78 | 9.8 | 8 | 156 | 0.50 | 156 | 0.50 | ||
| V70 | 78 | 4.9 | 16 | 78 | 1 | 78 | 1 | ||
| A40 | 156 | 2.4 | 64 | 156 | 1 | 313 | 0.5 | ||
| Herb extracts | |||||||||
| Sage | 313 | 4.9 | 64 | 156 | 2 | 156 | 2 | ||
| Peppermint | 156 | 9.8 | 16 | 156 | 1 | 156 | 1 | ||
| Lemon balm | 625 | 9.8 | 64 | 156 | 4 | 313 | 2 | ||
| Oregano | 1250 | 19.5 | 64 | 156 | 8 | 313 | 4 | ||
| Green tea | 156 | 9.8 | 16 | 78 | 2 | 78 | 2 | ||
| Thyme | 625 | 9.8 | 64 | 156 | 4 | 156 | 4 | ||
| Bearberry | 313 | 2.4 | 128 | 1,000 | 0.25 | 1,000 | 0.25 | ||
| Black seeds | 500 | 62.5 | 8 | 1,000 | 0.5 | 2,000 | 0.25 | ||
| Grape leaf extracts | |||||||||
| Lasin | 1,000 | 62.5 | 16 | 1,000 | 1 | 2,000 | 0.5 | ||
| Merlot | 1,000 | 62.5 | 16 | 1,000 | 1 | 2,000 | 0.5 | ||
| Vranac | 500 | 62.5 | 8 | 1,000 | 0.5 | 1,000 | 0.5 | ||
| Babić | 8,000 | 4,000 | 2 | 8,000 | 1 | 8,000 | 1 | ||
| Debit | 500 | 62.5 | 8 | 500 | 1 | 1,000 | 0.5 | ||
| Zlatarica | 1,000 | 31.3 | 32 | 500 | 2 | 500 | 2 | ||
| Kujundžuša | 4,000 | 62.5 | 64 | 2,000 | 2 | 2,000 | 2 | ||
| Rkaciteli | 4,000 | 62.5 | 64 | 2,000 | 2 | 2,000 | 2 | ||
| Trnjak | 2,000 | 500 | 4 | 500 | 4 | 1,000 | 2 | ||
| Rudežuša | 2,000 | 62.5 | 32 | 1,000 | 2 | 1,000 | 2 | ||
“Fold diff” depicts fold difference, which is calculated using the formula: MIC of 11168/MIC of a mutant strain. ≥4-fold changes are indicated in bold.
*
The MICs of 11168B are significantly lower than those of 11168 with phenolic compounds (P<0.05), rosemary extracts (P<0.01), herb extracts (P<0.01), and grape leaf extracts (P<0.01).