An epidemic of resistant Salmonella in a nursery. Animal-to-human spread.

A Salmonella heidelberg epidemic in a hospital nursery was traced to infected calves on a dairy farm where the mother of the index patient lived. The Salmonella isolates from all cases were resistant to chloramphenicol, sulfamethoxazole, and tetracycline. Verification of the spread of infection from the farm animals to a hospital population is unusual and raises questions about the hazards of antibiotic animal-feed preparations that may induce infection with resistant organisms in humans.