Transfer of Viral Communities between Human Individuals during Fecal Microbiota Transplantation

Transfer of whole communities of viruses between humans has rarely been studied but is of likely medical importance. Here we studied fecal microbiota transplantation (FMT), a highly successful treatment for relapsingClostridium difficileinfection and, potentially, other gastrointestinal (GI) diseases. We investigated the transfer of viral communities during FMT and documented transfer of multiple viral lineages between humans. None of these were viruses that replicated on animal cells or that are known to be pathogenic. We found that temperate bacteriophage, which form stable associations with their hosts, were significantly more likely to be transferred during FMT. This supports a model in which the viral temperate replication style may have evolved in part to support efficient viral transmission between environments.