School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
Westmead Institute for Medical Research, University of Sydney, Sydney, Australia.
PLoS One. 2020 Mar 11;15(3):e0229681. doi: 10.1371/journal.pone.0229681. eCollection 2020.
To determine whether Acanthamoeba keratitis (AK) patients have higher rates of Acanthamoeba and free-living amoeba (FLA) colonising domestic sinks than control contact lens (CL) wearers, and whether these isolates are genetically similar to the corneal isolates from their CL associated AK.
129 AK patients from Moorefield Eye Hospital, London and 64 control CL wearers from the Institute of Optometry were included in this study. The participants self-collected home kitchen and bathroom samples from tap-spouts, overflows and drains using an instructional kit. The samples were cultured by inoculating onto a non-nutrient agar plate seeded with Escherichia coli, incubated at 32°C and examined for amoebae by microscopy for up to 2 weeks. Partial sequences of mitochondrial cytochrome oxidase genes (coxA) of Acanthamoeba isolates from four AK patients were compared to Acanthamoeba isolated from the patient's home. The association between sampling sites was analysed with the chi-square test.
A total of 513 samples from AK patients and 189 from CL controls were collected. The yield of FLA was significantly greater in patients' bathrooms (72.1%) than CL controls' bathrooms (53.4%) (p<0.05). Spouts (kitchen 6.7%, bathroom 11%) had the lowest rate of Acanthamoeba isolation compared to drains (kitchen 18.2%, bathroom 27.9%) and overflow (kitchen 39.1%, bathroom 25.9%) either in kitchens or bathrooms (p<0.05). There was no statistically significant difference between the average prevalence of Acanthamoeba in all three sample sites in kitchens (16.9%) compared to all three sample sites in bathrooms (21.5%) and no association for Acanthamoeba prevalence between AK patients and CL controls. All four corneal isolates had the same coxA sequence as at least one domestic water isolate from the patients' sink of the kitchen and the bathroom.
The prevalence of Acanthamoeba and FLA was high in UK homes. FLA colonisation was higher in AK patients compared to controls but the prevalence of Acanthamoeba between AK patients and CL controls domestic sinks was similar. This study confirms that domestic water isolates are probably the source of AK infection. Advice about avoiding water contact when using CL's should be mandatory.
确定棘阿米巴角膜炎（AK）患者家中水槽中的棘阿米巴和自由生活阿米巴（FLA）定植率是否高于对照组接触镜（CL）佩戴者，以及这些分离株与角膜分离株是否具有遗传相似性来自他们的 CL 相关 AK。
本研究纳入了来自伦敦摩尔菲尔德眼科医院的 129 名 AK 患者和来自验光学院的 64 名对照组 CL 佩戴者。参与者使用指导工具包从水龙头、溢出物和排水管中自行采集家庭厨房和浴室样本。将样本接种到非营养琼脂平板上，接种大肠埃希菌，在 32°C 下孵育，并通过显微镜检查最多 2 周以检查阿米巴。对来自四名 AK 患者的棘阿米巴分离株的线粒体细胞色素氧化酶基因（coxA）的部分序列进行比较，从患者家中分离出的棘阿米巴。用卡方检验分析采样部位之间的关系。
共采集 AK 患者 513 例和 CL 对照组 189 例。患者浴室（72.1%）中 FLA 的产量明显高于 CL 对照组的浴室（53.4%）（p<0.05）。与厨房排水口（厨房 18.2%，浴室 27.9%）和溢出物（厨房 39.1%，浴室 25.9%）相比，龙头（厨房 6.7%，浴室 11%）的棘阿米巴分离率最低无论是在厨房还是浴室（p<0.05）。厨房所有三个采样点的棘阿米巴平均流行率（16.9%）与浴室所有三个采样点的平均流行率（21.5%）相比没有统计学差异，AK 患者和 CL 对照组之间的棘阿米巴流行率也没有关联。来自患者厨房和浴室水槽的 domestic water 分离株的至少一个 domestic water 分离株与来自患者角膜的所有四个分离株都具有相同的 coxA 序列。
英国家庭中棘阿米巴和 FLA 的流行率很高。与对照组相比，AK 患者中 FLA 的定植率更高，但 AK 患者和 CL 对照组家庭水槽中棘阿米巴的流行率相似。本研究证实，家庭用水分离株可能是 AK 感染的来源。在使用 CL 时应强制避免接触水的建议。
