Pediatric Salmonella Infection Workup

Updated: Dec 08, 2021
  • Author: Archana Chatterjee, MD, PhD; Chief Editor: Russell W Steele, MD  more...
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Laboratory Studies

The following tests are indicated in Salmonella infection:

  • CBC count with differential

    • CBC count is often 10,000-15,000/μ L in simple gastroenteritis.

    • Patients with enteric fever commonly have anemia, thrombocytopenia, or neutropenia, although a shift to more immature forms can be seen on the differential count.

  • Cultures

    • Isolation of Salmonella from cultures of stool, blood, urine, or bone marrow is diagnostic (see the image below).

      Under a moderately-high magnification of 8000X, th Under a moderately-high magnification of 8000X, this colorized scanning electron micrograph (SEM) revealed the presence of a small grouping of gram-negative Salmonella typhimurium bacteria that had been isolated from a pure culture. Image courtesy of the Centers for Disease Control and Prevention, Bette Jensen, and Janice Haney Carr.
    • Cultures of rose spots and/or bone marrow aspirate may be positive in enteric fever even when stool culture findings are negative for Salmonella.

  • Stool examination: Stool may be Hemoccult positive and may have positive findings for fecal polymorphonuclear cells.

  • Chemistry

    • Electrolyte tests may reveal metabolic acidosis or other abnormalities consistent with dehydration.

    • Patients with enteric fever may have mild hepatitis.

  • Serologic tests: Tests for Salmonella agglutinins (febrile agglutinins, Widal test) may suggest infection with S. typhi; however, they are not recommended because of the number of false-positive and false-negative results.


Imaging Studies

Imaging studies are not necessary for most patients with simple gastroenteritis and enteric fever without any severe complications.

Consider chest radiography if pneumonia is suggested as the result of bacteremia. Perform abdominal radiography if the patient presents with peritoneal signs on physical examination. Consider intestinal perforation as a complication of enteric fever.

Perform a bone scan if osteomyelitis is considered as a complication of bacteremia. MRI, which is more sensitive, is preferred to evaluate osteomyelitis.