Bacteriophages or phages

Viruses which use bacteria as host cells

Bacteriophages consist of nucleic acid encased in a protein shell. Like other viruses, they have no metabolism of their own and specialise in certain species of bacteria. This specificity is exploited in medicine to diagnose bacterial infections (lysotypy). In (microbial) genetic engineering, bacteriophages are used as vectors to transport foreign genes to bacteria.