SARS-CoV-2 Isolates from Urine, Placenta, and Nasopharyngeal Samples Reveal No Evidence of Tissue-Specific Mutation Signatures

We conducted a comparative mutation analysis of <b>SARS-CoV-2 sequences isolated from urine, placenta, and nasopharyngeal samples</b>, using Nextclade outputs to identify potential tissue-specific evolutionary patterns. Our findings indicate:<b>No Spike mutations were unique to non-respiratory tissues </b>(urine/placenta), suggesting that these isolates do not reflect adaptation to ACE2-expressing organs.<b>Private mutations were observed across all tissue types </b>, but none were shared across tissues or clustered in specific proteins, indicating general intra-host evolution rather than compartmentalized replication.<b>Mutation profiles were largely uniform </b>across biological matrices, consistent with systemic viremia rather than localized adaptation.These results support the hypothesis that <b>SARS-CoV-2 presence in non-respiratory tissues reflects generalized infection rather than tissue-specific evolution or tropism </b>. This baseline data may inform future studies exploring viral persistence or extrapulmonary shedding.

本研究针对从尿液、胎盘及鼻咽样本中分离得到的**严重急性呼吸综合征冠状病毒2（SARS-CoV-2）序列**开展比较突变分析，借助Nextclade的输出结果识别潜在的组织特异性进化模式。研究结果显示：**非呼吸组织（尿液/胎盘来源）未出现特异性刺突蛋白（Spike）突变**，提示上述分离株并未体现出对表达血管紧张素转换酶2（ACE2）器官的适应性。**各组织类型样本中均检测到私有突变，但未出现跨组织共享的突变，也未在特定蛋白中发生聚集**，表明病毒整体上呈现宿主内泛化进化特征，而非分区复制。**各类生物样本中的突变谱整体趋于一致**，与系统性病毒血症的表现相符，而非局部组织适应性变化。上述结果支持以下假说：**严重急性呼吸综合征冠状病毒2（SARS-CoV-2）在非呼吸组织中的存在，反映的是全身性感染，而非组织特异性进化或组织嗜性**。本研究获得的基础数据可为后续探索病毒持久性或肺外排毒的相关研究提供参考。