How to quantify bacterial cultures From CFU and OD to counting chamber Eppendorf US E coli cultures hi res stock photography and images Alamy Genetically engineered E. coli could improve drug development Texas A&M University Engineering Escherichia coli: essential and potentially dangerous. Not all E. coli is a problem. Many strains are part of the intestinal microbiota, contributing to vitamin synthesis and maintaining digestive balance. However,