Salmonellae cause a broad range of infections, including gastroenteritis, enteric fever, bacteremia, endovascular infections, and focal infections such as osteomyelitis and abscesses. Salmonellae are facultative anaerobic gram-negative bacilli and usually enter the body via the gastrointestinal (GI) tract, where they can persist for long periods of time. Salmonellae can act as both commensals and pathogens and are found in the GI tracts of domestic and wild animals, including insects, reptiles, birds, and mammals.
Although there are many types of Salmonella, they can be divided into two broad categories: those that cause typhoid and enteric fever and those that primarily induce gastroenteritis:
The bacterial and host factors that contribute to Salmonella gastroenteritis will be reviewed here (figure 1). The approach to patients with Salmonella in a stool culture is discussed separately. (See "Approach to the patient with nontyphoidal Salmonella in a stool culture".)
A number of different serovars of Salmonella cause human infection. The source of infection typically is from food.