School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA, Australia.
Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Adelaide, SA, Australia.
J Appl Microbiol. 2019 Jul;127(1):99-108. doi: 10.1111/jam.14298. Epub 2019 May 21.
The antimicrobial activity of cinnamon essential oil and cinnamaldehyde against bacterial and fungal pathogens associated with canine otitis externa, as well as the effect of their combination with EDTA were investigated.
Antimicrobial susceptibility testing was performed using the broth microdilution method while spot-plating technique was used to determine their bactericidal activity. Time-kill kinetics and checkerboard assays were performed to confirm the bactericidal activity and combination effects of the compounds. Cinnamon oil and cinnamaldehyde exhibited antimicrobial activity against Gram-positive and Gram-negative pathogens, as well as Malassezia pachydermatis. Synergistic interaction was shown when EDTA (672 μg ml ) was combined with cinnamon oil (41 μg ml ) and cinnamaldehyde (22 μg ml ) against Pseudomonas aeruginosa. Cinnamaldehyde exhibited significantly stronger antimicrobial activity than cinnamon bark oil.
Cinnamon essential oil and cinnamaldehyde, either used alone or in combination with EDTA, were effective against the causative micro-organisms of canine otitis externa. The data suggest that cinnamaldehyde could be a promising antimicrobial agent against canine otitis externa.
This study shows that cinnamon essential oil and cinnamaldehyde, especially the latter, could be used in combination with EDTA as novel treatment for sensitive and resistant bacterial and fungal pathogens involved in canine otitis externa.
研究肉桂精油和肉桂醛对与犬外耳炎相关的细菌和真菌病原体的抗菌活性，以及它们与 EDTA 联合使用的效果。
使用肉汤微量稀释法进行抗菌药敏试验，同时使用点平板技术测定其杀菌活性。进行时间杀伤动力学和棋盘试验以确认化合物的杀菌活性和组合效果。肉桂油和肉桂醛对革兰氏阳性和革兰氏阴性病原体以及厚皮马拉色菌均具有抗菌活性。当 EDTA（672μg/ml）与肉桂油（41μg/ml）和肉桂醛（22μg/ml）联合使用时，对铜绿假单胞菌显示出协同相互作用。肉桂醛的抗菌活性明显强于肉桂树皮油。
肉桂精油和肉桂醛单独使用或与 EDTA 联合使用，对犬外耳炎的致病微生物均有效。数据表明，肉桂醛可能是一种有前途的犬外耳炎抗菌药物。
本研究表明，肉桂精油和肉桂醛，特别是后者，可与 EDTA 联合用作治疗犬外耳炎中涉及的敏感和耐药细菌和真菌病原体的新型治疗方法。
