## 4 Conclusions  
Recent advancements have deepened our understanding of the gut microbiome's complexity and its pivotal role in host health. Investigations into prokaryotic diversity have identified distinct enterotypes across various species, underscoring both inter- and intraindividual variations in microbial composition. Growing evidence also points to the important role of the human gut phageome in shaping microbial communities and host interactions.  
Notably, the gut virome, particularly the prevalence of crAsslike phages (classified under the order _Crassvirales_), has garnered significant attention. Initially discovered in human faecal metagenomes, these bacteriophages predominantly infect bacteria within the phylum _Bacteroidota_. Emerging evidence suggests that crAsslike phages are not exclusive to humans; they have also been detected in the gut microbiota of other animals, including termites, as well as in ocean water samples, indicating a broader ecological distribution.  
Faecal microbiota transplantation has emerged as an effective therapeutic strategy for restoring gut microbial balance, particularly in cases of recurrent _Clostridioides difficile_ infections. Beyond bacterial components, the potential benefits of transferring viral communities, or the virome, are being explored. This approach aims to reestablish a comprehensive microbial ecosystem, offering promising avenues for treating a variety of conditions. Possible future solutions, including genetically engineering microbes to affect their metabolism and interactions with other organisms, could provide additional avenues for efficient, targeted therapy. However, much remains to be done to better understand the interactions among bacteria, viruses, and the host--at this moment, not much is known about bacteriophages that could infect probiotic bacteria and disrupt the healthy microbiome of the gut, therefore acting as indirect human and animal pathogens. The data on long-term results of the procedures--especially FVT--also seem to be lacking, so there is definitely significant potential for studies that could prove the permanence of beneficial changes in the intestinal microbiota.  
In summary, integrating knowledge of gut microbial diversity, enterotype classification, and the therapeutic potential of microbiota and virome transplants offers new perspectives in medical science. Continued research in these domains is essential for developing personalized therapies and promoting optimal gut health across different species.  
Conceptualization, W.J., M.M., and P.N.; writing--original draft preparation, W.J.; writing--review and editing, W.J., M.M., and P.N.; visualization, W.J.; supervision, M.M. and P.N.; funding acquisition, P.N. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
**Acknowledgments:** The authors would like to thank the following content creators for distributing the works that were used for the preparation of diagrams under Creative Commons licenses: [PERSON] (NIH BIOART)--human intestines, bacteria, Gram-negative bacterium, cow, rat (cropped, modified colours)--CCO 1.0; [PERSON] (bioicons.com)--Eppendorf tubes--CC-BY 4.0; [PERSON] (scidraw.io)--Falcon tube (cropped, modified colours)--CC-BY 4.0; [PERSON] (scidraw.io)--oblong bacterium with flagella--CCO 1.0; [PERSON] (scidraw.io)--_E. coli_--CCO 1.0; [PERSON] (scidraw.io)--plasmid--CC-BY 1.0; Contributors from Servier Medical Art--bacteriophages, capsule (modified colours)--CC-BY 4.0; Contributors from NIAID (NIH BIOART)--chicken (modified colours)--CCO 1.0; [PERSON] (Wikimedia Commons)--sheep (modified colours)--CC 1.0. Figures in this manuscript were prepared in Canva (Canva Pty. Ltd.).  
**Conflicts of Interest:** The authors declare no conflicts of interest.