PDF(Pubmed)
Abstract：
Quantitative microbial risk assessment (QMRA) can be used to evaluate health risks associated with recreational beach use. This study developed a site-specific risk assessment using a novel approach that combined quantitative PCR-based measurement of microbial source tracking (MST) genetic markers (human, dog, and gull fecal bacteria) with a QMRA analysis of potential pathogen risk. Water samples (n = 24) from two recreational beaches were collected and analyzed for MST markers as part of a broader Beach Exposure And Child Health Study that examined child behavior interactions with the beach environment. We report here the measurements of fecal bacteria MST markers in the environmental DNA extracts of those samples and a QMRA analysis of potential health risks utilizing the results from the MST measurements in the water samples. Human-specific Bacteroides was enumerated by the HF183 Taqman qPCR assay, gull-specific Catellicoccus was enumerated by the Gull2 qPCR assay, and dog-specific Bacteroides was enumerated by the DogBact qPCR assay. Derived reference pathogen doses, calculated from the MST marker concentrations detected in recreational waters, were used to estimate the risk of gastrointestinal illness for both children and adults. Dose-response equations were used to estimate the probability of the risk of infection (Pinf) per a swimming exposure event. Based on the QMRA simulations presented in this study, the GI risk from swimming or playing in water containing a mixture of human and non-human fecal sources appear to be primarily driven by the human fecal source. However, the estimated median GI health risk for both beaches never exceeded the U.S. EPA risk threshold of 32 illnesses per 1,000 recreation events. Our research suggests that utilizing QMRA together with MST can further extend our understanding of potential recreational bather risk by identifying the source contributing the greatest risk in a particular location, therefore informing beach management responses and decision-making.
摘要：
定量微生物风险评估（QMRA）可用于评估与休闲海滩使用相关的健康风险。这项研究使用一种新颖的方法开发了特定于站点的风险评估，该方法结合了基于定量PCR的微生物来源追踪（MST）遗传标记的测量（人类，狗,和鸥粪便细菌），并对潜在的病原体风险进行QMRA分析。收集了两个休闲海滩的水样（n=24），并分析了MST标记，作为更广泛的海滩暴露和儿童健康研究的一部分，该研究检查了儿童行为与海滩环境的相互作用。我们在这里报告了这些样品的环境DNA提取物中粪便细菌MST标记的测量结果，以及利用水样中MST测量结果对潜在健康风险的QMRA分析。人类特异性拟杆菌通过HF183TaqmanqPCR测定法进行计数，通过Gull2qPCR检测对海鸥特异性Catellicocus进行了计数，和狗特异性拟杆菌通过DogBactqPCR分析进行计数。来源的参考病原体剂量，根据在娱乐水域检测到的MST标记浓度计算，用于估计儿童和成人胃肠道疾病的风险。使用剂量反应方程来估计每次游泳暴露事件的感染风险（Pinf）的概率。基于本研究中提出的QMRA模拟，在含有人类和非人类粪便来源混合物的水中游泳或玩耍的胃肠道风险似乎主要由人类粪便来源驱动。然而,两个海滩的GI健康风险估计中位数从未超过美国EPA风险阈值,即每1,000个娱乐活动中有32种疾病.我们的研究表明，利用QMRA与MST一起可以进一步扩大我们对潜在的休闲沐浴风险的理解，通过识别在特定位置造成最大风险的来源，因此，通知海滩管理响应和决策。
