E. coli is the most known and studied bacteria belonging to the genus Escherichia. It is a Gram negative, used in microbiology as an experimental model microorganism since it is easy to isolate, cultivate, of rapid replication and very resistant to manipulation. In humans, it is the most diffuse and predominant bacterial species in the intestine, especially at the level of the colon. However, it is able to migrate to other districts of the body to establish infection, especially in the urinary tract in particular the strain carrying the K antigen, where it can persist for long periods of time, chronicizing the infection with the formation of biofilm, causing resistance to the main antibiotics. The E. coli uropathogenic strains (UPEC) are responsible for about 90% of uncomplicated cystitis. In the first stage of the infectious process, the adhesins located in the upper part of the fimbrias represent the adhesive factor that allows E. coli to adhere firmly to the urothelium. The true infection is released from emolysin A, which, as a small sharp scissors, can damage the urinary epithelium, damaging it and promoting chemotaxis, an acute and chronic inflammation with the invasion of bordering tissues and high global health risk for the organism.