Arida Joseph, Shipley Alicia, Almeria Sonia
Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), Food and Drug Administration, 8301 Muirkirk Road, Laurel, MD 20708, USA.
Joint Institute for Food Safety and Applied Nutrition (JIFSAN), University of Maryland, College Park, MD 20742, USA.
Microorganisms. 2023 Jun 6;11(6):1506. doi: 10.3390/microorganisms11061506.
is a foodborne protozoan parasite that causes outbreaks of diarrheal illness (cyclosporiasis) with clear seasonality worldwide. In the environment, oocysts are very robust, and contact with contaminated soil may serve as an important vehicle in the transmission of this organism, and it is considered a risk factor for this infection. The present study evaluated a flotation concentration method, previously shown to provide the best detection results when compared with DNA isolation directly from soil samples, in two main types of farm soil, silt loam soil and sandy clay loam, as well as in commercial potting mix samples inoculated with different numbers of oocysts. The flotation method was able to detect as few as 10 oocysts in 10 g of either type of farm soil without modifications, but needed an extra wash and samples of reduced size for the processing of the commercial potting mix to be able to detect 20 oocysts/5 g. A recently modified real-time PCR method for the detection of based on a mitochondrial gene target was also evaluated using selected samples of each type of soil. This comparative study confirmed that the concentration of oocysts in soil samples by flotation in high-density sucrose solutions is a sensitive method that can detect low numbers of oocysts in different types of soil.
是一种食源性原生动物寄生虫，可导致腹泻疾病（环孢子虫病）在全球范围内爆发，并具有明显的季节性。在环境中，卵囊非常坚韧，接触受污染的土壤可能是这种生物体传播的重要媒介，并且被认为是这种感染的一个风险因素。本研究评估了一种浮选浓缩方法，该方法先前已被证明与直接从土壤样本中分离DNA相比能提供最佳检测结果，该方法应用于两种主要类型的农田土壤（粉质壤土和砂质粘壤土）以及接种了不同数量卵囊的商业盆栽混合样本中。在不做修改的情况下，浮选法能够在10克任何一种类型的农田土壤中检测到低至10个卵囊，但对于商业盆栽混合样本的处理，需要额外冲洗并减小样本量才能检测到20个卵囊/5克。还使用每种类型土壤的选定样本评估了一种最近改进的基于线粒体基因靶点检测的实时PCR方法。这项比较研究证实，通过在高密度蔗糖溶液中浮选来浓缩土壤样本中的卵囊是一种灵敏的方法，能够检测不同类型土壤中的少量卵囊。
