A species of bacteria (from the family Enterobacteraceae) that normally lives in the guts of people and animals. Most E. coli strains are harmless and play an essential role in keeping the digestive system healthy, helping to digest food and producing Vitamin K. However, some E. coli bacteria are pathogenic and can cause disease. The harmful serotypes can be transmitted through contaminated water or food or through contact with animals or other infected people.
