Escherichia coli O121 is a serotype

Serotype

Serotype or serovar refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens...

 of Escherichia coli

Escherichia coli

Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

, a species of bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 that lives in the lower intestines of mammals. The presence of many serotypes of E. coli in animals is beneficial or does not cause disease. However, E. coli O121 has been recognized as a potential disease causing serotype of bacteria. Unlike Escherichia coli O157:H7

Escherichia coli O157:H7

Escherichia coli O157:H7 is an enterohemorrhagic strain of the bacterium Escherichia coli and a cause of foodborne illness. Infection often leads to hemorrhagic diarrhea, and occasionally to kidney failure, especially in young children and elderly persons...

, another pathogenic serotype of E. coli, little is known about the public health

Public health

Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...

 significance of O121.

Escherichia coli O121 is also known as a type of "non-O157 Shiga toxin

Shiga toxin

Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, whose genes are considered to be part of the genome of lambdoid prophages. The toxins are named for Kiyoshi Shiga, who first described the bacterial origin of dysentery caused by Shigella dysenteriae. The most common...

-producing E. coli" or "non-O157 STEC".