Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China.
School of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, Henan, 471000, China.
Int J Legal Med. 2024 Nov;138(6):2259-2269. doi: 10.1007/s00414-024-03277-1. Epub 2024 Jul 10.
As two kinds of increasingly popular pets, the saliva of cat or canine is most likely to be left at the crime scene compared with the common types of body fluids in forensics. Accurately identifying the species of saliva samples found at the crime scene involving pets will help the investigators find available testing materials, reduce the consumption of reagents and save the investigative time of the case. Therefore, it is necessary to explore the characteristics and differences of saliva microbiomes of cat, canine and human. In this study, 16S rRNA gene amplicon sequencing technology was used to reveal microbial communities of saliva samples of healthy human, cat, and canine. Alpha diversity analyses indicated that canine saliva demonstrated the highest microbial diversity, followed by cat saliva, whereas human saliva microbial diversity was the lowest. The saliva samples of the three species all had their own unique microbial community compositions, and the dominant phyla of canine and cat salivas were Proteobacteria and Bacteroidete, while the dominant phyla of human saliva were Firmicutes and Proteobacteria. There was no significant statistical difference in the salivary microbiota obtained by the two collection methods (cotton swab and liquid saliva). The gender of cats and canines might have no effect on the salivary microbiota, but the different breeds had an impact on their saliva microbiomes. Principal coordinates analysis, non-metric multidimensional scaling analysis and random forest analysis all indicated significant differences in microbial community structures among the three species, allowing inference on the species sources of saliva samples by microbiome method. Differential microbial biomarkers for the salivas of three species were screened out using a variety of bioinformatics analyses, and the results demonstrated that Prevotella melaninogenica, Veillonella parvula, and Haemophilus parainfluenzae could be used as species-specific microbial biomarkers of human saliva. The detections of human species-specific microbes provide a potential method for determining human saliva.
作为两种越来越受欢迎的宠物，猫或犬的唾液与法医中常见的体液相比，最有可能留在犯罪现场。准确识别涉及宠物的犯罪现场发现的唾液样本的物种将有助于调查人员找到可用的检测材料，减少试剂的消耗并节省案件的调查时间。因此，有必要探索猫、犬和人唾液微生物组的特征和差异。在这项研究中，使用 16S rRNA 基因扩增子测序技术揭示了健康人类、猫和犬唾液样本的微生物群落。Alpha 多样性分析表明，犬唾液显示出最高的微生物多样性，其次是猫唾液，而人唾液微生物多样性最低。这三种唾液样本都有其独特的微生物群落组成，犬和猫唾液的优势菌群为变形菌门和拟杆菌门，而人唾液的优势菌群为厚壁菌门和变形菌门。两种采集方法（棉签和唾液）获得的唾液微生物群没有显著的统计学差异。猫和犬的性别可能对唾液微生物群没有影响，但不同品种对其唾液微生物组有影响。主坐标分析、非度量多维尺度分析和随机森林分析均表明三种物种之间的微生物群落结构存在显著差异，通过微生物组方法可以推断唾液样本的物种来源。使用多种生物信息学分析筛选出三种唾液的差异微生物生物标志物，结果表明普雷沃氏菌黑色素原、小韦荣球菌和副流感嗜血杆菌可作为人唾液的种特异性微生物生物标志物。人种特异性微生物的检测为人唾液的检测提供了一种潜在的方法。
