CrAssphage has been recognized as the most abundant and human-specific bacteriophage in the human gut. Consequently, crAssphage has been used as a microbial source tracking (MST) marker to monitor human fecal contamination. Many crAss-like phages (CLPs) have been recently discovered, expanding the classification into the new order Crassvirales. This study aims to assess CLP prevalence in South Korea and develop a detection system for MST applications. Thirteen CLPs were identified in six human fecal samples and categorized into seven genera via metagenomic analysis. The major head protein (MHP) displayed increased sequence similarity within each genus. Eight PCR primer candidates, designed from MHP sequences, were evaluated in animal and human feces. CLPs were absent in animal feces except for those from raccoons, which hosted genera VI, VIIa, and VIIb. CLPs were detected in 91.52% (54/59) of humans, with genus VI (38 out of 59) showing the highest prevalence, nearly double that of p-crAssphage in genus I (22 out of 59). This study highlights genus VI as a potent MST marker, broadening the detection range for CLPs. Human-specific and selectively targeted MST markers can significantly impact hygiene regulations, lowering public health costs through their application in screening liver, sewage, wastewater, and various environmental samples.

中文翻译：

---

开发一种新型广谱 crAss 噬菌体检测方法，用于微生物来源追踪


CrAssphage 已被公认为人类肠道中含量最丰富的人类特异性噬菌体。因此，crAssphage 已被用作微生物来源追踪 （MST） 标记物来监测人类粪便污染。最近发现了许多 crAs 样噬菌体 （CLP），将分类扩展到新目 Crassvirales。本研究旨在评估韩国的 CLP 患病率，并为 MST 应用开发检测系统。在 6 个人类粪便样本中鉴定出 13 个 CLPs，并通过宏基因组分析分为 7 个属。主要头部蛋白 （MHP） 在每个属内表现出增加的序列相似性。在动物和人类粪便中评估了由 MHP 序列设计的 8 种 PCR 引物候选物。动物粪便中不存在 CLP，除了来自浣熊的粪便，浣熊是 VI、VIIa 和 VIIb 属的宿主。在 91.52% （54/59） 的人类中检测到 CLP，其中 VI 属（59 个中的 38 个）的患病率最高，几乎是 I 属 p-crAssphage 的两倍（59 个中的 22 个）。本研究强调 VI 属是一种有效的 MST 标志物，拓宽了 CLP 的检测范围。人类特异性和选择性靶向的 MST 标志物可以显着影响卫生法规，通过应用于筛查肝脏、污水、废水和各种环境样本来降低公共卫生成本。