Canine otitis externa is frequently encountered in veterinary practice, caused by primary factors with bacteria and yeast overgrowth acting as secondary and perpetuating factors. The pharmacological support includes anti-inflammatory, antimicrobials, and antimycotic drugs, but therapeutic failure and antimicrobial resistance are leading to alternative strategies based on phytotherapic products. This study aimed to evaluate an essential oil blend (Otogen^®) to treat otitis externa in dogs. The experimental design was divided in: (a) an in vitro approach, based on the European Normative UNI EN 1275:2006, to assess the efficacy of the product against the most frequently isolated microorganisms during otitis externa. (b) an in vivo part, 12 owned dogs presenting with acute otitis externa were enrolled. A significant growth reduction (>99.9%) of Malassezia pachydermatis and Candida albicans after 15 min of contact and Pseudomonas aeruginosa after 1 h of incubation was recorded. For Staphylococcus pseudintermedius, 50% of growth reduction were appreciated after 15 min. Results obtained in vivo after 7 days of blend administration, noted a significant improvement of all the considered parameters (most important were head shaking, erythema, and scraping). The results obtained may support the usefulness of the tested phytotherapic blend to manage acute otitis externa in dogs.

中文翻译：

---

一种新的植物疗法混合物治疗犬急性外耳炎的体外和体内评价

在兽医实践中经常遇到犬外耳炎，这是由主要因素引起的，细菌和酵母菌过度生长是次要因素和延续性因素。药理学支持包括抗炎药、抗微生物剂和抗真菌药，但治疗失败和抗微生物药物耐药性导致基于植物治疗产品的替代策略。本研究旨在评估一种精油混合物 (Otogen ^® ) 以治疗狗的外耳炎。实验设计分为：(a) 一种基于欧洲规范 UNI EN 1275:2006的体外方法，以评估产品对外耳炎期间最常分离的微生物的功效。(b)体内部分，12只患有急性外耳炎的自有犬入组。记录到在接触 15 分钟后马拉色菌和白色念珠菌的生长显着减少 (>99.9%)，在孵育 1 小时后记录到铜绿假单胞菌的显着生长减少 (>99.9%)。对于假中型葡萄球菌，15 分钟后可减少 50% 的生长。混合给药 7 天后体内获得的结果表明，所有考虑的参数都有显着改善（最重要的是摇头、红斑和刮擦）。获得的结果可能支持所测试的植物疗法混合物在治疗犬急性外耳炎方面的有用性。