What is Superinfection?
A superinfection is generally defined as a second infection superimposed on an earlier one, especially by a different microbial agent of exogenous or endogenous origin, that is resistant to the treatment used against the first infection. An example of this in bacteriology is the overgrowth of endogenous Clostridium difficile which occurs following treatment with a broad-spectrum antibiotic.
In virology, the definition is slightly different. Superinfection is the process by which a cell that has previously been infected by one virus gets co-infected with a different strain of the virus, or another virus, at a later point in time. Viral superinfections may be resistant to the antiviral drug or drugs that were being used to treat the original infection. Viral superinfections may also be less susceptible to the host's immune response.