Salmonella enterica is the name of a group of rod-shaped bacteria that can cause gastroenteritis in humans and other animals. Salmonella infections can have serious consequences for certain high-risk groups, such as babies, young children, the elderly and individuals whose immune systems are functionally compromised. Most people with a normal complement of gut microflora (microbiota) generally have little difficulty coping with such infections. Only in 10-20% of cases in which the pathogens are ingested—usually via contaminated food products—does an infection actually result. But the members of the gut microbiota that are responsible for resistance to Salmonella are largely unknown.