Antipseudomonal activity of Artemisia quettensis Podlech essential oil and its synergy with imipenem

Context: The problems associated with hospital infections caused by Pseudomonas aeruginosa, and the emergence of new and the re-emergence of old infectious diseases have become increasingly evident. Therefore, medicinal plants take precedence over the development of new antibacterial agents. The combination effects of antibiotics and plant compounds might be an appropriate solution for microbial resistance and useful method for assessment of synergistic interactions for inhibition of bacterial growth. This study is an experimental design for the discovery and finding of natural and harmless compounds for the treatment of infectious diseases. Aim: To determine the antibacterial potency of Artemisia quettensis essential oil, and in combination with imipenem, to inhibit the growth of Pseudomonas aeruginosa. Methods: The essential oil was obtained through hydrodistillation from aerial parts of the plant and analysis using GC and GC-MS. To demonstrate the in vitro antibacterial activity of the essential oil against Pseudomonas aeruginosa (ATCC 27853) disc diffusion assay was used, either alone or in combination with a standard antibiotic. Results: The most dominant components were homoadamantane (9.38%), Camphor (7.91%) and Eugenol (10.46%). The oil and antibiotic showed high antibacterial activity against Pseudomonas aeruginosa with minimal inhibitory concentration (MIC) 0.5 µL/mL and 16 µg/mL and minimal bactericidal concentration (MBC) 4 µL/mL and 32 µL/mL, respectively. The synergistic effect of the oil and antibiotic showed MIC 0.2 µL/mL and 4 µg/mL and MBC 2 µL/mL and 8 µL/mL, respectively. This study showed that Artemisia quettensis oil has significant antibacterial activity against Pseudomonas aeruginosa infections. Conclusions: The essential oil exhibited synergism with imipenem displaying the ability to enhance the activity of this compound and it may be useful in the fight against emerging microbial drug resistance.