Possible role of intestinal human viruses and bacteriophages following hematopoietic stem cell transplantation: a mini-review

Abstract

Gut microbiota (a complex community of bacteria, fungi and viruses) is a dynamic biological system adapted for co-existence and symbiosis with host organism. Composition and ratio of bacterial populations is severely impaired in severe colitis and graft-versus-host disease (GVHD) occurring after hematopoietic stem cell transplantation (HSCT), especially, upon development of antibiotic-resistant bacterial strains. In contrast to the well-known bacterial microbiota studied by classic bacteriology and 16S rRNA gene sequencing, the viral populations of intestinal microbiota (e.g., bacteriophages) in are poorly studied in these clinical conditions, due to absence of a common viral gene suitable for comparative molecular genetic analysis. Assessing the ratios for viral and bacterial intestinal microbiota is feasible by means of metagenomic methods assaying multiple DNA species in the samples of biomaterial. As an object of clinical research, the patients with infectious complications caused by massive antibacterial and cytostatic treatment. Special attention should be drawn to severe colitis with C.difficile infection and antibiotic-resistant K.pneumonia and other pathogens with/without fecal microbiota transplantation (FMT). Conventional assessment of intestinal microbiota will be accomplished by next-generation sequencing (NGS) based on 16S rDNA gene diversity for bacterial genes, and metagenomic NGS analysis, in order to assess the ratio of various viruses of eukaryotic cells and, in particular, bacteriophages in cases of gut dysbiosis. Typical disturbances of the gut virome should be established, as well as role of bacteriophages in emergence of antibiotic-resistant intestinal bacteria after intensive antibiotic and chemotherapy.

Origin and consequences of intestinal dysfunction following cytostatic chemotherapy and hematopoietic stem cell transplantation

“…There are several recent reviews concerning relative roles of eukaryotic cell viruses and bacteriophages in different disorders affecting gastrointestinal system [52,53]. E.g., sufficient attention is drawn to the inflammatory bowel disorders [54] which may be promoted by common viral infections, e.g., by noro-and rotavirus.…”