Strain

A strain is a subset of a bacterial species differing from other bacteria of the same species by some minor but identifiable difference.

A strain can also be defined as a population of organisms that descends from a single organism or pure culture isolate. Strains within a species may differ slightly from one another in many ways.

Strains are often created in the laboratory by mutagenizing existing strains or wild-type examples of bacterial species.

The term strain is also applicable to eukaryotic microorganisms, as well as to viruses.

Many diseases, including HIV/AIDS and hepatitis, have multiple strains.

Strain in mechanics can also refer to the volumetric deformation of a solid material subjected to external forces.