Only Gram-positive cells can be easily seen at this stage. Gram-negative cells are counterstained with the red dye carbol fuchsin, so that they, too, may be easily seen. Return to text . Bacteriophage are viruses that infect bacteria. Typically a bacteriophage infection results in bursting of the infected bacterium - a lytic infection.
Some bacteriophage can cause a stable infection, and the bacteriophage persists as a 'prophage'.
These are lysogenic infections. Return to text . The term prokaryote is derived from two Greek words pro- and karyon meaning 'before the nucleus'. Return to text . A pathogen is a micro-organism that can cause disease.