Salmonella infection
Salmonella infection splits into nontyphoidal disease, a usually self-limited foodborne gastroenteritis that can bacteremically seed bone and joints in sickle cell disease, and typhoidal disease (S. Typhi/Paratyphi), a prolonged travel-associated bacteremic enteric fever with stepwise fever, relative bradycardia, and rose spots. Nontyphoidal disease is diagnosed by stool culture and managed supportively, while enteric fever is diagnosed by blood culture and always treated with antibiotics.
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What this article covers
- Overview
Two clinically distinct diseases from one genus: nontyphoidal Salmonella serotypes cause an acute, usually self-limited foodborne gastroenteritis, while Salmonella enterica serotype Typhi and…
- Epidemiology
Nontyphoidal Salmonella is the leading foodborne bacterial pathogen in the United States, transmitted through fecally contaminated food or water, most often poultry, beef, eggs, and milk.
- Risk factors
Undercooked or contaminated animal-source food: poultry, eggs, beef, and unpasteurized milk are the leading nontyphoidal exposures.
- Pathophysiology
Ingestion and mucosal invasion: both forms begin with ingestion of the organism, which invades the intestinal epithelium; nontyphoidal serotypes provoke a local inflammatory enteritis, while…
- Clinical features
Nontyphoidal gastroenteritis: crampy abdominal pain, fever, diarrhea that is not usually visibly bloody, headache, nausea, and vomiting, beginning within 3 days of exposure.
- Differential diagnosis
Shigella infection: dysentery with tenesmus, small-volume bloody/mucoid stools, and high fever, more prominently bloody and a lower infecting dose (shigella infection).
- Diagnosis
Confirm nontyphoidal infection with stool culture or NAAT: a positive stool study establishes the diagnosis; blood cultures are added when invasive or severe disease is suspected.
- Management
Nontyphoidal gastroenteritis, start with supportive care: oral rehydration or IV fluids for volume losses; antibiotics are not routine because they do not shorten uncomplicated illness and can prolong fecal shedding.
- Complications
Intestinal hemorrhage or perforation: occurs 2 to 3 weeks into untreated enteric fever from ileal Peyer patch necrosis, a surgical emergency.
- Prognosis
Nontyphoidal gastroenteritis is self-limited in healthy hosts: most uncomplicated infections in adults younger than 50 years resolve within about a week without antibiotics.
- Prevention
Food safety practices for nontyphoidal disease: cook poultry, beef, and eggs to safe internal temperatures, avoid unpasteurized milk, and wash hands after handling reptiles or amphibians.
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