Department of Pathology and Legal Medicine, Postgraduate Program in Medical Microbiology, Group of Applied Medical Microbiology, Federal University of Ceará, Rua Cel. Nunes de Melo, 1315, Rodolfo Teófilo, CEP: 60430-275, Fortaleza, Ceará, Brazil.
Department of Pathology and Legal Medicine, Postgraduate Program in Medical Microbiology, Specialized Medical Mycology Center, Federal University of Ceará, Rua Cel. Nunes de Melo, 1315, Rodolfo Teófilo, CEP: 60430-275, Fortaleza, Ceará, Brazil.
Microb Pathog. 2024 Nov;196:106993. doi: 10.1016/j.micpath.2024.106993. Epub 2024 Oct 5.
Otitis externa is an inflammatory disease of the external ear canal of complex and multifactorial etiology associated with recurrent bacterial infection. This study aimed to assess the antimicrobial and antibiofilm activity of promethazine against bacterial isolates from dogs with otitis externa, as well as the effect of this compound on the dynamics of biofilm formation over 120 h. Planktonic bacterial susceptibility to promethazine was evaluated to determine the minimum inhibitory concentrations (MIC). The minimum biofilm eradication concentration (MBEC) was also determined by broth microdilution. To evaluate the effect on biofilm growth, promethazine was tested at three concentrations MIC, MIC/2 and MIC/8, with daily readings at 48, 72, 96 and 120 h. The MICs of promethazine ranged from 48.83 to 781.25 μg mL. Promethazine significantly (P < 0.05) reduced mature biofilm biomass, with MBECs ranging from 48.8 to 6250 μg mL and reduced (P < 0.01) biofilm formation for up to the 120-h, at concentrations corresponding to the MIC obtained against each isolate. Promethazine was effective against microorganisms associated with canine otitis externa. The data suggest that promethazine presents antimicrobial and antibiofilm activity and is a potential alternative to treat and prevent recurrent bacterial otitis in dogs. These results emphasize the importance of drug repurposing in veterinary otology as an alternative to reduce antimicrobial resistance.
外耳炎是一种复杂的多因素病因引起的外耳炎炎症性疾病，与复发性细菌感染有关。本研究旨在评估异丙嗪对患有外耳炎的犬分离细菌的抗菌和抗生物膜活性，以及该化合物对 120 小时内生物膜形成动力学的影响。通过肉汤微量稀释法评估了游离态细菌对异丙嗪的敏感性，以确定最小抑菌浓度（MIC）。最小生物膜消除浓度（MBEC）也通过肉汤微量稀释法确定。为了评估对生物膜生长的影响，在 MIC、MIC/2 和 MIC/8 三个浓度下测试了异丙嗪，并在 48、72、96 和 120 小时进行每日读数。异丙嗪的 MIC 值范围为 48.83 至 781.25 μg mL。异丙嗪显著（P<0.05）降低成熟生物膜生物量，MBEC 值范围为 48.8 至 6250 μg mL，并在 120 小时内减少生物膜形成（P<0.01），浓度对应于针对每种分离物获得的 MIC。异丙嗪对与犬外耳炎相关的微生物有效。这些数据表明，异丙嗪具有抗菌和抗生物膜活性，是治疗和预防犬复发性细菌性耳炎的潜在替代药物。这些结果强调了在兽医耳科学中重新利用药物作为减少抗菌药物耐药性的替代方法的重要性。
