Together Forever: Bacterial–Viral Interactions in Infection and Immunity

Most viruses first encounter host cells at mucosal surfaces, which are typically colonized by a complex ecosystem of microbes collectively referred to as the microbiota. Recent studies demonstrate the microbiota plays an important role in mediating host–viral interactions and determining the outcomes of these encounters. This review outlines recently described examples of how bacteria and viruses impact each other particularly during infectious processes. Mechanistically, these effects can be broadly categorized as reflecting direct bacterial–viral interactions and/or involving microbial impacts upon innate and/or adaptive immunity.