What is a common route of transmission for Escherichia coli O157:H7?

• A. Ingestion of undercooked ground beef
• B. Inhalation of aerosols
• C. Skin contact with contaminated surfaces
• D. Person-to-person droplet transmission

Answer: (A)

Escherichia coli O157:H7 is transmitted primarily through the fecal-oral route, most commonly by consuming contaminated food. Ground beef is a classic source because grinding distributes any surface contamination throughout the meat, and if it isn’t cooked to a safe internal temperature, viable bacteria can be ingested. Once inside the body, the organism can cause severe gastrointestinal illness due to Shiga toxin. Emphasizing safe cooking to an appropriate internal temperature helps prevent infection. Other routes like inhalation, skin contact with surfaces, or droplet transmission are not typical pathways for this enteric pathogen, since it’s spread mainly by ingestion of contaminated material rather than respiratory or casual contact.