Escherichia coli (E. coli) is defined as a facultative anaerobic, gram-negative, rod-shaped bacterium, consisting of hundreds of different serotypes and extremely versatile. These serotypes range from harmless strains that play a vital role in maintaining intestinal function, to strains that contain pathogenic properties that infect the human body and cause distinct signs and symptoms. Pathogenic strains of Escherichia coli are capable of causing three common clinical diseases including sepsis/meningitis, urinary tract infection, and enteric diarrhea. The pathogenic E. coli is known to be extremely diverse, adaptable, and contains various virulence factors that influence a wide range of cellular processes. Therefore, pathogenic Escherichia coli is extensively studied in foods, mammals, and the environment. E. coli-associated disease outbreaks are common in developed and developing countries and represent an important problem in public health and epidemiological studies. Commensal isolate (E. coli HS) that commonly inhabits the normal microflora of the human and animal gastrointestinal tract. E. coli HS is a bacterium that can be easily grown in the laboratory and has easily manipulated genetics. This E. coli HS serotype is O9 and contains many syntenic sequences with other E. coli genomes. E. Coli HS has 94 genes unique to its serotype, while 64 of these genes show no functional annotation. The only genes with functional annotations are associated with the production of serogroup O9 lipopolsaccharide. This type of E. coli can be identified by…..stains of the O1f7:H7 serotype of Escherichia coli, a strain that is the cause of foodborne diseases and epidemics in humans……middle of paper……ng based on the system Kauffman classification, pulsed-field gel electrophoresis (PFGE), miltilocutus variable number tandem repeat analysis (MVLA), multilocus sequence typing (MLST). THE. coli pathogen can also be classified phylogenetically into 5 main groups, defined as A, B1, B2, D and E, with Shigella toxin forming in different groups. THE. coli commensal that populates the normal flora of the lower intestine is grouped in phylogroup A. Based on the variety of colonization and virulence factors linked to each pathotype, there is no single method that can be used to diagnose and detect all pathogenic Escherichia coli filaments. Therefore, numerous biochemical tests, molecular approaches and typing methods have been developed to isolate and identify E. coli from other bacteria that populate the organism and to distinguish the different pathotypes of E. coli.