CBRNE - Glanders and Melioidosis Workup

Updated: Aug 16, 2015
  • Author: Paul P Rega, MD, FACEP; Chief Editor: Duane C Caneva, MD, MSc  more...
  • Print
Workup

Laboratory Studies

Basic laboratory tests include the following:

  • Complete blood cell count (CBC)
  • Liver function studies
  • Gram stain and culture of blood, sputum, urine, and skin lesions

The CBC may reveal a mild leukocytosis with a left shift or leukopenia. With glanders, the white blood cell count (WBC) is often normal or minimally elevated. Elevated liver enzyme levels in glanders may signify hepatic abscess formation. In melioidosis specifically, laboratory studies may demonstrate anemia, leukocytosis, hepatic impairment, renal insufficiency, and coagulopathy.

Gram stain may reveal small, gram-negative bacilli, which stain irregularly with methylene blue or Wright stain, and they may demonstrate a safety pin bipolar appearance. Blood culture results may be negative. The median time for growth is 48 hours. In septicemic melioidosis, blood culture results may be negative until just before death. Meat nutrient agar or the addition of 1-5% glucose may accelerate growth of bacteria. Another useful culture medium for B pseudomallei is Ashdown's selective medium.

Other tests include the following

  • Agglutination tests: Agglutination test results may be positive after 7-10 days, but a high background titer found in normal sera makes interpretation difficult.
  • Indirect hemagglutination tests
  • Polymerase chain reaction assays
  • Immunofluorescence assays
  • Enzyme immunoassays
  • Complement fixation tests

Complement fixation tests are more specific and are considered positive for glanders if the titer is 1:20 or greater. A 4-fold increase in the titer for melioidosis is considered positive.

Next:

Imaging Studies

Chest radiography may demonstrate bilateral bronchopneumonia, miliary nodules, segmental or lobar infiltrates, and cavitating lesions. With melioidosis, an abnormal chest radiography finding is present in up to 80% of patients (usually diffuse nodular shadowing).

Ultrasonography and computed tomography may reveal multiple, small discrete abscesses in both the liver and the spleen. These findings are highly suggestive of visceral melioidosis. [14]

Bone and soft tissue musculoskeletal involvement may be seen with plain radiographs and magnetic resonance imaging. These findings are consistent with disseminated melioidosis. [14]

Previous