Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Eye (Lond). 2022 Oct;36(10):1911-1917. doi: 10.1038/s41433-021-01768-8. Epub 2021 Sep 21.
Acanthamoeba keratitis (AK) is an important cause of ocular morbidity in both contact lens wearers and non wearers. Medical management comprises prolonged empiric treatment with multiple drugs, leading to adverse effects and suboptimal cure. The present study evaluated the efficiency and safety of common antimicrobial agents used in treatment of AK.
Six Acanthamoeba isolates (four AK, two water samples) were axenized and subjected to in vitro susceptibility testing against chlorhexidine, pentamidine isethionate, polymyxin B, miltefosine, and fluconazole to check for trophocidal and cysticidal activity. The safety profile was analysed by observing the cytotoxicity of the highest cidal concentration toward human corneal epithelial cell (HCEC) line.
Chlorhexidine had the lowest cidal concentration against both cysts and trophozoites (range 4.16-25 μg/ml) followed by pentamidine isethionate (range 25-166.7 μg/ml). Both agents were nontoxic to HCEC. Polymyxin B (range 25-200 μg/ml) and fluconazole (range 64-512 μg/ml) had relatively higher minimum inhibitory concentrations (MIC); fluconazole was nontoxic even at 1024 μg/ml, but cytotoxicity was observed at 400 μg/ml with polymyxin B. Miltefosine was not effective against cysts at tested concentrations. A. castellanii were more susceptible to all agents (except pentamidine isethionate) than A. lenticulata. Clinical isolates were less susceptible to polymyxin B and fluconazole than environmental isolates, reverse was true for miltefosine.
Chlorhexidine and pentamidine isethionate were the most effective and safe agents against both trophozoites and cysts forms of our Acanthamoeba isolates. Fluconazole had higher MIC but was nontoxic. Polymyxin B was effective at high MIC but therapeutic dose was found toxic. Miltefosine, at tested concentrations, could not inhibit cysts of Acanthamoeba. Clinical isolates had higher MICs for polymyxin B and fluconazole.
棘阿米巴角膜炎（AK）是戴隐形眼镜者和非戴隐形眼镜者眼部发病率的重要原因。医学治疗包括长期使用多种药物进行经验性治疗，导致不良反应和治疗效果不理想。本研究评估了用于治疗 AK 的常用抗菌药物的疗效和安全性。
将 6 株棘阿米巴分离株（4 株 AK，2 株水样）去滋养体并进行体外药敏试验，以评估氯己定、戊烷脒、多黏菌素 B、米替福新和氟康唑对滋养体和包囊的杀活力。通过观察最高杀菌浓度对人角膜上皮细胞（HCEC）系的细胞毒性来分析安全性概况。
氯己定对包囊和滋养体的最低杀菌浓度最低（范围为 4.16-25μg/ml），其次是戊烷脒（范围为 25-166.7μg/ml）。两种药物对 HCEC 均无毒性。多黏菌素 B（范围为 25-200μg/ml）和氟康唑（范围为 64-512μg/ml）的最小抑菌浓度（MIC）相对较高；氟康唑在 1024μg/ml 时甚至没有毒性，但在 400μg/ml 时观察到多黏菌素 B 的细胞毒性。米替福新在测试浓度下对包囊无效。与 A. lenticulata 相比，A. castellanii 对所有药物（除戊烷脒外）更敏感。临床分离株对多黏菌素 B 和氟康唑的敏感性低于环境分离株，而米替福新则相反。
氯己定和戊烷脒是针对我们的棘阿米巴分离株的滋养体和包囊形式最有效和安全的药物。氟康唑的 MIC 较高，但无毒性。多黏菌素 B 在高 MIC 时有效，但治疗剂量被发现有毒。米替福新在测试浓度下不能抑制棘阿米巴包囊。临床分离株对多黏菌素 B 和氟康唑的 MIC 较高。
