We all have lots of E. Coli, essential E. coli in our bodies, and most E. Coli bugs are harmless and just live there and we live with them very well. But there are some E. Coli which are called pathogenic.
In other words, they can cause disease and the disease is usually diarrhoea, a form of diarrhoea. But it also can get into your bloodstream and cause Septicemia so that you can get quite serious infections with E. Coli. There’s no way from the symptoms really that you would know that you had E. Coli infection.
It’s usually from culturing the poo or culturing your blood that you discover that you’ve got E. Coli infection. So it’s nothing particular about E. Coli.