Table 1.
Essential oils (EOs) and volatile compounds modulating the antibiotic activity against Acinetobacter baumannii.
| Essential Oil/Volatile Compound | Vegetal Source | Major Constituent | Acinetobacter baumannii Strain | Antibiotic | Method | Effect | Ref. |
|---|---|---|---|---|---|---|---|
| Tea tree EO | Melaleucae folium (Melaleuca alternifolia (Maiden. and Beach.) Cheel., Myrtaceae, Tea tree) | Terpinen-4-ol (30.3%) | ATCC 19606 | Gentamicin | CB (FICI = 0.5) | S | [34] |
| Myrtle EO | Myrti folium (Myrtus communis L., Myrtaceae, Myrtle) | Linalool (22.276%) Myrtenyl acetate (16.561%) 1,8-Cineole (13.250%) |
ATCC 19606 ATCC BAA747 and 22 clinical isolates of which MDR strains: Aba-6637, Aba-4914, Aba-5055 | Ciprofloxacin | CB (FICI < 0.5) TK |
S | [24] |
| Linalool (18.320%) Myrtenyl acetate (18.009%) 1,8-Cineole (16.878%) | |||||||
| Polymyxin B | S | ||||||
| Linalool (26.591%) Myrtenyl acetate (18.489%) 1,8-Cineole (15.762%) | |||||||
| Longbeak eucalyptus EO | Eucalypti folium (Eucalyptus camaldulensis Dehnh., Myrtaceae, Longbeak eucalyptus) | Spathulenol (18.90%) | Aba-4914 Aba-5055 |
Ciprofloxacin | CB (FICI < 0.5) | S | [25] |
| Aba-6673 | CB (FICI = 0.53) | Ad | |||||
| Aba-4914 Aba-6673 |
Gentamicin | CB (FICI < 0.5) | S | ||||
| Spathulenol (21.39%) | |||||||
| CB (FICI = 0.5) | Ad | ||||||
| ATCC 19606 Aba-4914 Aba-5055 |
Polymyxin B | CB (FICI < 0.5) TK |
S | ||||
| Rosewood EO | Anibae lignum (Aniba rosaeodora Ducke, Lauraceae, Rosewood) | Linalool (60.1%) | ATCC 19606 | Gentamicin | CB (FICI = 0.11) | S | [34] |
| Cinnamon EO | Cinnamomi cortex (Cinnamomum zeylanicum Nees, Lauraceae, Cinnamon) | - | Clinical isolate A-06 | Amikacin | CB (FICI = 0.045) | S | [40] |
| Gentamicin | CB (FICI = 0.5) | Ad | |||||
| Imipenem | CB (FICI = 2) | I | |||||
| Meropenem | CB (FICI = 1.5) | I | |||||
| Coriander EO | Coriandri fructus (Coriandrum sativum L., Apiaceae, Coriander) | - | LMG 1025 | Cefoperazone | CB (FICI = 0.750) | Ad | [30] |
| Chloramphenicol | CB (FICI = 0.312) | S | |||||
| Ciprofloxacin | CB (FICI = 0.281) | S | |||||
| Gentamicin | CB (FICI = 0.250) | S | |||||
| Piperacillin | CB (FICI = 1) | Ad | |||||
| Tetracycline | CB (FICI = 0.312) | S | |||||
| LMG 1041 | Cefoperazone | CB (FICI = 1) | Ad | ||||
| Chloramphenicol | CB (FICI = 0.047) | S | |||||
| Ciprofloxacin | CB (FICI = 0.375) | S | |||||
| Gentamicin | CB (FICI = 0.375) | S | |||||
| Piperacillin | CB (FICI = 0.625) | Ad | |||||
| Tetracycline | CB (FICI = 0.185) | S | |||||
| Immortelle EO | Helichrysi flos (Helichrysum italicum (Roth) G. Don, Asteraceae, Immortelle) | - | ATCC 19606 Clinical isolate AB1 |
Chloramphenicol | FR (8-fold reduction in MIC) | S | [37] |
| Oregano EO | Origani herba (Origanum vulgare Linn., Lamiaceae, Oregano) | Cymenol (58.6%) | ATCC 19606 | Gentamicin | CB (FICI = 0.65) | Ad | [34] |
| Geranium EO | Pelargonii herba (Pelargonium graveolens L., Geraniaceae, Geranium) | Citronellol (47.3%) | ATCC 19606 | Gentamicin | CB (FICI = 0.11) | S | |
| Lemon EO | Citri pericarpium (Citrus limon L. Burm. F., Rutaceae, Lemon) | - | Clinical isolate A-06 | Amikacin | CB (FICI = 0.037) | S | [40] |
| Gentamicin | CB (FICI = 0.5) | Ad | |||||
| Imipenem | CB (FICI = 2) | I | |||||
| Meropenem | CB (FICI = 2) | I |
Ad: addition; S: synergy; I: indifference; CB: checkerboard assay; TK: time kill assay; FICI: fractional inhibitory concentration index; FR: fold reduction in MIC; MIC: minimum inhibitory concentration; MDR: multidrug-resistant.