Hi, thank you for a simple introduction to E. coli, the organism that I am also working on. I would like to add a bit more about the pathogenic side of E. coli. According to the recently released report from WHO's Global Antimicrobial Resistance Surveillance System (GLASS), E. coli is the species most reported from 44 countries participating in the system, indicating the high burden of E. coli in causing infections in human. You can view GLASS data by country here.

E. coli is the most frequent cause of community and hospital-acquired urinary tract infections, the most frequent cause of bloodstream infection at all ages, and also one of the leading causes of food-borne infections worldwide. The burden of E. coli infections is further complicated by the increasing rate of antimicrobial resistant E. coli worldwide, limiting the treatment option for E. coli infected patients.

For many scientists using E. coli as a tools to study biology/microbiology, it is a close friend that help them further scientific advances, but let's not forget that out there in the wild it is the leading causes of human infections worldwide.