Commentary: With a little help from my enteric microbial friends.

Abstract

In a recent mini-review published in Frontiers in Medicine, Ben Berkhout pointed out that the interactions between co-localizing viruses and commensal bacteria in the gastric tract are important for the survival and transmission of a number of virus families (Berkhout, 2015). These viruses are part of the virome or viral metagenome that constitutes the total collection of viruses found in and on a multicellular organism (Wylie et al., 2012). Moreover, he highlighted that these close interactions between bacteria and viruses that constitute the microbiome are important also because they may provide opportunities for treatment or even prevention of disease through the modulation of these interactions. The mini-review furnishes a number of examples of interactions between viruses and bacteria in the gut, including the retrovirus mouse mammary tumor virus (MMTV), the archetypal milk borne virus. As mentioned in the review article, MMTV is a member of the Retroviridae that notably also includes the human disease associated members human immunodeficiency virus (HIV) and human T-cell leukemia virus (HTLV), both of which can also be transmitted to infants by breast feeding. Transmission can occur either by infection with free virions or by delivery of infected cells/cell associated virus where the virus is then transferred through virological synapses that are formed between an infected source cell and a susceptible target cell (Komarova and Wodarz, 2013). Berkhout's mini-review is interesting and to our knowledge is the first time that the cross virus family relevance of interaction between viruses that infect multicellular eukaryotes and commensal bacteria has been highlighted as a possible general phenomenon. However, we feel that some additional information and some novel points can be brought to the table, specifically with respect to retroviruses. Moreover, the situation with respect to bacterial interaction may be more complicated than was presented, at least for retroviruses and possibly also for other members of the virome.