Analogous example:- different strains of chocolate icecream can be based on it's varying texture, taste, color like:- choco-almond, chocolate chip , chocolate mint, milk chocolate, (plain, dark, vanilla) etc
In the same manner, It's a particular type of bacteria among its genetic brethren with differences based upon serological or morphological or genetic characters.
Like in bacterial terms some bacteria of same class and genus and specie show varying response to antimicrobial compounds.
Some are resistant some are susceptible this difference is a classical example of bacterial strains.
MRSA (Multi resistant Staphylococcus Aureus) is a particular strain in the species Staphylococcus aureus.
A strain is somewhat analogous to a race in humans. People in a race have certain characteristics that differentiate them from another race, yet we all belong to the same species (although some forget that). Organisms of a strain have certain characteristics that differentiate them. Usually, the characteristics are founded in the genetics of the organism.
