04 Nov


Bacteriophages are viruses that infect bacterial cells.  In 1915 Twort and d”Herelle noticed that their bacterial cultures were disappearing and the culture would be cleared from the medium.  They also noticed that the liquid left behind would clear new cultures of bacteria.  They concluded that the bacterial cultures were being eaten by some unknown force and coined the phrase bacteriophage which means “bacteria eater.”  Bacteriophages or phages for short are similar to other viruses in that they are obligate intracellular parasites and must invade a host cell in order to replicate and reproduce.  This is because viruses are composed of a one nucleic acid molecule and a protein coat or capsid.  They lack the proteins necessary to reproduce and must use the host cells components to replicate.  Viruses are very specific and may only infect a specific strain of bacteria.  This is beneficial if one is attempting to eliminate a known species of bacteria.