Mouse Anti-Bacteriophage Matrix protein 13 Monoclonal antibody for IHC, ELISA, FC, IP, WB. A bacteriophage is any one of a number of viruses that infect bacteria. Bacteriophages are among the most common biological entities on Earth. The term is commonly used in its shortened form, phage.Typically, bacteriophages consist of an outer protein capsid enclosing genetic material. The genetic material can be ssRNA, dsRNA, ssDNA, or dsDNA (ss- or ds- prefix denotes single-strand or double-strand) along with either circular or linear arrangement.