What does a really heavy growth escherichia coli mean?

See below: I assume you are referring to the culture of some type of secretion or wound. This means that there are many gram negative bacilli of the species e.Coli growing on the culture plate that was innoculated with the specimen. The e. Coli might be causing an infection or could be colonizing depending on the type of specimen, amount of wbc's on the gram stain and the clinical signs.