Escherichia coli (E. coli) Gram-negative Brevibacterium, 0.5 *1-3 micron in size. Peripheral flagellum, motile, sporeless. It can ferment a variety of carbohydrates to produce acid and gas. It is the normal inhabitant bacteria in human and animal intestines. After birth, infants enter the intestinal tract with lactation and accompany people for life, accounting for almost one third of the dry weight of feces.
The antigenic components of E. coli are complex and can be divided into bacterial antigen (O), flagellum antigen (H) and surface antigen (K), which have the ability of anti-body phagocytosis and anti-complement. According to the different antigens, E. coli can be divided into more than 150 types, of which 16 serotypes are pathogenic E. coli, which often causes epidemic infantile diarrhea and adult pleurisy.
Escherichia coli is the most important and abundant bacteria in the intestine of human beings and many animals. It has flagella all over its body and can move without spores. They mainly live in the large intestine.
Escherichia coli is a kind of bacteria closely related to our daily life. Its scientific name is "Escherichia coli", and it belongs to one of the large categories of intestinal bacteria. Within hours of a baby's birth, E. coli settles in the intestine through swallowing. Normally, most Escherichia coli are very safe. They will not only bring any harm to our health, but also resist the attack of pathogenic bacteria competitively. They can also help to synthesize vitamin K2, which is a mutually beneficial symbiotic relationship with the human body. Only under special circumstances such as low immunity and long-term lack of stimulation of intestinal tract can these good people make waves and migrate to places outside intestinal tract, such as gallbladder, urethra, bladder and appendix, causing infection in corresponding parts or disseminated infection in the whole body. Therefore, most Escherichia coli are usually considered opportunistic pathogens.
E. coli O157:H7 is one of the