How are pathogenic E coli different from other E coli?

Since it is E. coli, I assume they should be pathogenic.

Escherichia, the genus name of E. Coli. It is named after Theodor Escherich, who had discovered the bacterium.

Escherichia coli (commonly abbreviated E. coli; pronounced /ˌɛʃɨˈrɪkiə ˈkoʊlaɪ/, named after Theodor Escherich) is a Gram negative rod-shaped bacterium that is commonly found in the lower...

Escherichia (the genus name).

Because E. Coli is short for it's scientific name, Escherichia Coli. And you wouldn't want to have to say that constantly in science class, would you? :)