摘要

       最近，crAssphage 已被提议作为跟踪粪便污染的人类特异性标记物。然而，它的性能一直在有限数量的宿主样本中得到验证，这可能会掩盖我们对其效用的理解。此外，很少有研究量化使用 crAssphage 时粪便污染的可信度。在这里，我们通过分析大量宏基因组数据集并结合贝叶斯分析来评估 crAssphage 的性能和置信度。结果表明 crAssphage 表现出优异的性能，具有高宿主敏感性和特异性，表明其适用于跟踪人类粪便来源。使用标记，可以获得高置信度 (>90%)，尤其是具有阳性结果的多个样本提供了近乎确定的置信度。 crAssphage 在中国三个城市河流的沉积物中的应用显示了> 97% 的人类粪便污染的高置信度，表明这些环境中污水污染的严峻挑战。此外，在crAssphage和抗生素抗性基因（ARGs）之间观察到显着相关性，扩大了crAssphage在ARGs污染管理中的利用。这项研究强调了在即将到来的大数据时代，随着可用宏基因组数据资源的增加，使用基于宏基因组的分析来评估微生物源跟踪标记的性能和置信度的好处。

       Recently, crAssphage has been proposed as a human-specific marker for tracking fecal contamination. However, its performance has always been validated in a limited number of host samples, which may obscure our understanding of its utility. Furthermore, few studies have quantified confidence of fecal contamination when using crAssphage. Here, we evaluate the performance and confidence of crAssphage by analyzing a large panel of metagenomic data sets combined with Bayesian analyses. Results demonstrate that crAssphage exhibits superior performance with high host sensitivity and specificity, indicating its suitability for tracking human fecal sources. With the marker, a high confidence (>90%) can be obtained and particularly, multiple samples with positive results provide a near certainty of confidence. The application of crAssphage in the sediments of three Chinese urban rivers shows a high confidence of >97% of human fecal contamination, suggesting the serious challenge of sewage pollution in these environments. Additionally, significant correlation is observed between crAssphage and antibiotic resistance genes (ARGs), expanding the utilization of crAssphage for pollution management of ARGs. This study highlights the benefit of using metagenomic-based analysis for evaluating the performance and confidence of microbial source tracking markers in the coming era of big data with increasing resources in available metagenomic data.

https://pubs.acs.org/doi/abs/10.1021/acs.est.1c00071