Salmonella species are capable of survival in a wide range of niches, both in the environment and in an infected host. Genetic requirements for survival of Salmonella in different niches have traditionally been identified using gene expression and forward genetics.
Enteric fevers are caused by the human-specific pathogens Salmonella enterica serovars Typhi and Paratyphi. The name "enteric fever" reflects the route of acquisition, as infection of the gastrointestinal (GI) tract through exposure to contaminated food and water eventually causes systematic dissemination of bacteria leading to disease.
Salmonella lives in the intestinal tract of humans and other animals, including birds. Salmonella is usually transmitted to humans by eating foods contaminated with animal feces. Salmonella present on raw meat and poultry could survive if the product is not cooked to a safe minimum internal temperature, as measured with a food thermometer.
Salmonella bacteria are the most frequently reported cause of foodborne illness. The Salmonella family includes over 2,300 serotypes of bacteria which are one-celled organisms too small to be seen without a microscope. Two types, Salmonella Enteritidis and Salmonella Typhimurium are the most common in the United States and account for half of all human infections.
Any person can get salmonellosis, but it is diagnosed more often in infants and children. Young children, the elderly, and the immunocompromised are the most likely to have severe infections.
Salmonella infections usually resolve in five to seven days and often do not require treatment unless the patient becomes severely dehydrated or the infection spreads from the intestines. Those with severe diarrhea may require rehydration, often with intravenous fluids. Antibiotics are usually not necessary unless the infection spreads from the intestines.
Since salmonellae are acquired through ingestion of contaminated foodstuffs, sanitary means of control are most important. Treatment of animal feeds reduces the overall level of organisms in the animal population, improved slaughtering practices prevent cross-contamination of animal products and proper hygienics by food-handlers prevents contamination at the consumer level.
The source of organisms for Salmonella gastroenteritis include contaminated food or water. Most commonly, persons acquire Salmonella from contaminated poultry (turkeys and chickens). S. enteritidis or S. choleraesuis are the most commonly isolated species.
Every year, approximately 42,000 cases of salmonellosis are reported in the United States. Because many milder cases are not diagnosed or reported, the actual number of infections may be twenty-nine or more times greater.
Salmonellosis is an infection with bacteria called Salmonella. Salmonella germs have been known to cause illness for over 100 years. They were discovered by an American scientist named Salmon, for whom they are named.