This scanning electron micrograph (SEM) depicts a number of highly magnified rod-shaped, motile, Gram-negative Salmonella infantis bacteria, some of which are attached, Magnification 18875x. Salmonellosis is an infection due to members of a genus of bacteria called Salmonella, of which S. infantis is a member. Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment. However, in some persons the diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites and can cause death unless the person is treated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are more likely to have severe illness. See image n0830305 on the site.