Antimicrobial Activity of Combined Cinnamon Nanoemulsions-Antibiotics against Acinetobacter baumannii

Threats of Acinetobacter baumannii, a Gram-negative and multi-drug resistant bacterium,to the public health have recently received great attention worldwide. This is because the high incidence rate of the bacterial infections and the ability of the A. baumannii to resist a wide range of antibiotics. This study is designed to investigate the antimicrobial activity of the cinnamon oil in water as Nano emulsions (NEs) alone and in combination with different antibiotics against clinical isolate of A. baumannii.  At the beginning, the minimum inhibitory concentration (MIC) of different antibiotics and also cinnamon Nano emulsions (CNEs) are determined. Later, the synergistic effect of the CNEs with each of the studied antibiotics is also examined. Results showed that the bacterium has the highest resistant towards ampicillin (MIC = 700 µg/ml), followed by kanamycin, and gentamycin with MIC of each of the antibiotics was 200µg/ml and 150 µg/ml, respectively. Cinnamon Nano emulsions (CNEs) were also showed a profound inhibitory effect on A. baummanii. Interestingly, combinations of cinnamon Nano emulsions (CNEs) with either kanamycin or gentamycin, but not ampicillin, show a significant increase in the antimicrobial activity of each of the antibiotics compared to when they were used alone. The results of this study strongly suggest the potential application of CNEs in combination with antibiotics to overcome A. baummanii infections.