- Infection caused by any serotype of the bacterial genus Salmonella, a gram-negative facultatively anaerobic bacillus
- Nontyphoidal Salmonella typically causes gastroenteritis via foodborne infection and sporadic outbreaks; less commonly causes infection outside the gastrointestinal (GI) tract
- Clinical syndromes
- Enteric fever (see “Typhoid Fever”)
- Nontyphoidal gastroenteritis
- Chronic carrier state (>1 year)
- Nontyphoidal invasive disease
- Endovascular complications
- Localized infection outside GI tract (i.e., osteomyelitis, abscess)
Patients >65 years old have increased risk of invasive disease with bacteremia and endovascular complications due to comorbidities (atherosclerotic endovascular lesions, prostheses, etc.) that increase risk of bacterial seeding.
Neonates (<3 months) are more susceptible to invasive disease and complications.
- Global incidence of nontyphoidal Salmonella enteritidis estimated to be ~94 million per year (mostly foodborne)
- Wide variation by region from 40 to 3,980 estimated cases per 100,000
- Global incidence of invasive nontyphoidal Salmonella infection estimated to be 535,000 cases in 2017
- Most commonly identified foodborne bacterial illness in the United States and a common cause of traveler’s diarrhea.
- Estimated 1.4 million cases per year in the United States, with annual incidence of 15 illnesses per 100,000
- Second most common bacteria isolated from stool cultures in diarrheal illness (following Campylobacter) in the United States
- Highest incidence of bacteremia in children <5 years old
- Hospitalization rates higher in patients >50 years old
- Peak frequency: July to November
Etiology and Pathophysiology
- Salmonella enterica
- Most pathogenic species in humans
- 2,500 different serotypes
- ~95% of cases are foodborne.
- Other cases (5%) are due to direct or indirect fecal–oral contact with animals or human carriers.
- Iatrogenic contamination (e.g., blood transfusion, endoscopy) is rare.
- Typical infectious dose in immunocompetent patients is ingestion of 1 million bacteria but can be lower in patients taking antibiotics or in the setting of gastric acid reduction.
- Bacteria ingested invade the distal ileal and proximal colonic mucosa to produce an inflammatory and cytotoxic response.
- Bacteria can enter the mesenteric lymphatic system and then the systemic circulation to cause disseminated/invasive disease.
- Recent travel to underdeveloped nations
- Consumption of undercooked meat, egg, or unpasteurized dairy products. Nonanimal products have also been implicated in outbreaks.
- Contact with live reptiles or poultry
- Contact with human carrier (Salmonella fecal shedding)
- Impaired gastric acidity: H2 receptor blockers, antacids, proton pump inhibitors (PPIs), gastrectomy, achlorhydria, pernicious anemia, infants
- Recent antibiotic use
- Reticuloendothelial blockade: sickle cell disease, malaria, bartonellosis
- Immunosuppression: HIV, diabetes, corticosteroid or other immunosuppressant use, chemotherapy
- Impaired phagocytic function: chronic granulomatous disease, hemoglobinopathies, malaria
- Age <5 years or >50 years
- Proper hygiene in production, transport, and storage of food (e.g., refrigeration during food storage and thoroughly cooking food prior to consumption)
- Control of animal reservoirs: Avoid contact with high-risk animals, feces, and polluted waters.
- Hand hygiene
- CDC tracks outbreaks (http://www.cdc.gov/salmonella/).
Commonly Associated Conditions
- Bacteremia: immunocompromised or patients with underlying disease (e.g., cholelithiasis, prostheses)
- Osteomyelitis: higher incidence in sickle cell disease
- Abscesses: higher incidence with malignant tumors
- Reactive arthritis
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Domino, Frank J., et al., editors. "Salmonella Infection." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688782/all/Salmonella_Infection.
Salmonella Infection. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688782/all/Salmonella_Infection. Accessed May 30, 2023.
Salmonella Infection. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688782/all/Salmonella_Infection
Salmonella Infection [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 May 30]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688782/all/Salmonella_Infection.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Salmonella Infection ID - 1688782 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688782/all/Salmonella_Infection PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -