Bacteriophages of the Human Virome

Bacteriophages are found throughout the human body.

They may even outnumber eukaryotic viruses, forming an important and dynamic component of the human virome.

In the gut, bacteriophages may integrate their genome, carrying beneficial genes for antibiotic resistance or specialized metabolism into the bacterial genome through lysogenic conversion.

These genetic transfers may alter the stability and resilience of the gut microbiota, particularly under selective pressures such as antibiotic exposures.

On mucosal surfaces, bacteriophages bind via capsid proteins to mucin glycoproteins, concentrating at the epithelial barrier and forming a defense against invading bacteria.

These phages can kill the invading bacteria before they reach epithelial cells, protecting the host.

Some bacteriophages enhance bacterial pathogenicity.

For example, the CTXϕ bacteriophage injects genes encoding cholera toxin into Vibrio cholerae. Strains lysogenized by CTXϕ become pathogenic, produce cholera toxin, and infect the host gut epithelium.