Department of Medical Technology, Osaka University Hospital, Osaka, Japan; Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Osaka, Japan.
Department of Medical Technology, Osaka University Hospital, Osaka, Japan.
Ophthalmology. 2014 Oct;121(10):2059-65. doi: 10.1016/j.ophtha.2014.04.013. Epub 2014 May 29.
To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK).
Laboratory research.
Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied.
The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0% povidone-iodine, 0.05% benzalkonium chloride (BZC), 0.02% chlorhexidine gluconate (CHG), 0.1% propamidine isethionate, 0.02% polyhexamethylene biguanide (PHMB), 5.0% natamycin, and 1.0% voriconazole (VRCZ). These concentrations are those recommended for patients. In addition, 10-fold dilutions of each of the agents were tested. After exposing the cysts to each agent at 35°C for 1 hour or 24 hours, the agents were removed by centrifugal washing. The exposed cysts were observed by optical microscopy for 7 days. In addition, the fine structures of the exposed isolates were examined by transmission electron microscopy (TEM). The genotype of the isolates was determined by 18S rDNA fragment sequencing.
The in vitro susceptibility was determined by complete growth inhibition, and the morphologic appearance was determined by TEM. The genotypes of the 56 isolates were determined by 18S rDNA fragment sequencing.
The Acanthamoeba cysts were most susceptible to natamycin, followed by povidone-iodine, BZC, PHMB, propamidine, and CHG. None of the strains was susceptible to VRCZ. The susceptibilities to PHMB and CHG may be time dependent and to propamidine may be concentration dependent. Transmission electron microscopy showed changes in the inner structure of the cysts exposed to natamycin and povidone-iodine. The Acanthamoeba genotype was T4 in 52 isolates, and cysts with the same genotype had different agent susceptibilities.
Natamycin and povidone-iodine had excellent cysti-static (or cystcidal) effects, and PHMB and propamidine did not. There was no correlation between agent effectiveness and Acanthamoeba genotype. Therefore, susceptibility tests of isolates are needed to choose the most appropriate agent, and our results can be a guideline for choosing the most appropriate agent for immediate empirical treatment of AK.
评估局部药物治疗棘阿米巴角膜炎（AK）的效果。
实验室研究。
从 56 名临床确诊 AK 患者的 56 个分离株中进行研究。
在体外测定了 7 种药物对棘阿米巴包囊的效果。这些药物为 1.0%聚维酮碘、0.05%苯扎氯铵（BZC）、0.02%葡萄糖酸氯己定（CHG）、0.1%普罗米丁碘化物、0.02%聚六亚甲基双胍（PHMB）、5.0%那他霉素和 1.0%伏立康唑（VRCZ）。这些浓度是推荐给患者的浓度。此外，还测试了每种药物的 10 倍稀释液。将包囊在 35°C 下暴露于每种药物 1 小时或 24 小时后，通过离心洗涤去除药物。用光学显微镜观察暴露的包囊 7 天。此外，通过透射电子显微镜（TEM）观察暴露分离物的精细结构。通过 18S rDNA 片段测序确定分离物的基因型。
通过完全生长抑制确定体外敏感性，并通过 TEM 确定形态外观。通过 18S rDNA 片段测序确定 56 个分离物的基因型。
棘阿米巴包囊对那他霉素最敏感，其次是聚维酮碘、BZC、PHMB、普罗米丁和 CHG。没有一种菌株对 VRCZ 敏感。对 PHMB 和 CHG 的敏感性可能是时间依赖性的，对普罗米丁的敏感性可能是浓度依赖性的。透射电子显微镜显示暴露于那他霉素和聚维酮碘的包囊内部结构发生变化。52 个分离物的棘阿米巴基因型为 T4，具有相同基因型的包囊对不同药物的敏感性不同。
那他霉素和聚维酮碘具有优异的杀包囊（或杀包囊）作用，而 PHMB 和普罗米丁则没有。药物效果与棘阿米巴基因型之间没有相关性。因此，需要对分离物进行药敏试验，以选择最合适的药物，我们的结果可以作为选择最适合 AK 即刻经验性治疗的药物的指南。
