Enteric Bacteria

What Are the Enteric Bacteria of Concern?

The intestines of all animals, including commonly used laboratory animals, are colonized by a large number of microbes most of which are harmless. Others are harmless in normal individuals but can produce disease in the very young, those with weakened immune systems, or in a new host that has no prior experience with the microbe. Some bacteria are much more pathogenic and can produce disease in normal individuals on a regular basis. The following are a few of the enteric bacteria most often associated with disease in humans:

  • Campylobacter jejuni
  • Escherichia coli (pathogenic strains)
  • Salmonella species
  • Shigella species

Routes of Infection

The transmission of all these organisms to man is by the fecal-oral route. Material contaminated by the feces of animals must be put directly into the person’s mouth. Animals may also transmit these diseases to people. In order to become infected, the human must place material from the animal’s feces directly in his or her mouth. People do this when they fail to wash their hands after handling animals.


The highest risk is associated with young animals with diarrhea. Good ways to infect yourself would be to eat or drink in the animal facility or to fail to wash your hands before eating, drinking, or smoking after working with animals.


The single most effective preventive measure that you could take to protect yourself would be thorough, regular hand washing with soap and warm water after handling animals, especially young animals with diarrhea. If you work with young animals with diarrhea, and you develop intestinal signs, you should report the illness to your supervisor and consult with a physician at Employee Health Services (860-679-2893).