Remesh Arun Thachappully, Viswanathan Rajlakshmi
Bacteriology Group, ICMR - National Institute of Virology, Pune, Maharashtra, India.
Food Environ Virol. 2024 Jun;16(2):121-135. doi: 10.1007/s12560-024-09584-5. Epub 2024 Feb 27.
CrAss-like phages are a diverse group of bacteriophages genetically similar to the prototypical crAssphage (p-crAssphage), which was discovered in the human gut microbiome through a metagenomics approach. It was identified as a ubiquitous and highly abundant bacteriophage group in the gut microbiome. Initial co-occurrence analysis postulated Bacteroides spp. as the prospective bacterial host. Subsequent studies have confirmed multiple host species under Phylum Bacteroidetes and some Firmicutes. Detection of crAss-like phages in sewage-contaminated environmental water and robust correlation with enteric viruses and bacteria has culminated in their adoption as a microbial source tracking (MST) marker. Polymerase chain reaction (PCR) and real-time PCR assays have been developed utilizing the conserved genes in the p-crAssphage genome to detect human fecal contamination of different water sources, with high specificity. Numerous investigations have examined the implications of crAss-like phages in diverse disease conditions, including ulcerative colitis, obesity and metabolic syndrome, autism spectrum disorders, rheumatoid arthritis, atopic eczema, and other autoimmune disorders. These studies have unveiled associations between certain diseases and diminished abundance and diversity of crAss-like phages. This review offers insights into the diverse aspects of research on crAss-like phages, including their discovery, genomic characteristics, structure, taxonomy, isolation, molecular detection, application as an MST marker, and role as a gut microbiome modulator with consequential health implications.
类crAss噬菌体是一类多样的噬菌体，在基因上与原型crAss噬菌体（p-crAssphage）相似，后者是通过宏基因组学方法在人类肠道微生物群中发现的。它被确定为肠道微生物群中普遍存在且高度丰富的噬菌体群体。最初的共现分析推测拟杆菌属为潜在的细菌宿主。随后的研究证实了拟杆菌门和一些厚壁菌门中的多种宿主物种。在受污水污染的环境水中检测到类crAss噬菌体，并且其与肠道病毒和细菌有很强的相关性，这最终使其被用作微生物源追踪（MST）标记。利用p-crAssphage基因组中的保守基因开发了聚合酶链反应（PCR）和实时PCR检测方法，以检测不同水源中的人类粪便污染，具有很高的特异性。许多研究探讨了类crAss噬菌体在多种疾病状况中的影响，包括溃疡性结肠炎、肥胖症和代谢综合征、自闭症谱系障碍、类风湿性关节炎、特应性皮炎和其他自身免疫性疾病。这些研究揭示了某些疾病与类crAss噬菌体丰度和多样性降低之间的关联。本综述深入探讨了类crAss噬菌体研究的各个方面，包括它们的发现、基因组特征、结构、分类学、分离、分子检测、作为MST标记的应用以及作为肠道微生物群调节剂的作用及其对健康的影响。
