The case of a pregnant woman, infected with Salmonella heidelberg, who worked on a farm until 4 days before delivery. Her baby subsequently developed mild diarrhea, as did 2 others sharing the hospital nursery. Salmonella heidelberg was isolated from each, and in all cases was resistant to chloramphenicol, sulfamethoxazole, and tetracycline. The strain originated from a herd of infected farm animals.