Anthrax - Finding It and Analyzing It

To find and analyze anthrax, there are basically two types of testing. One is done in a routine clinical laboratory for microbiology. The other test involves genetic analysis by DNA fingerprinting.

Clinical Laboratory Testing

To obtain samples of anthrax and test them in a routine clinical microbiology laboratory, the following steps are needed to confirm the presence of anthrax:

  1. Gather samples -- Swabs are taken of the nasal passages and any skin lesions of persons possibly exposed to anthrax. Samples of sputum, blood and spinal fluid may also be taken from persons who have symptoms. Swabs may be taken of surfaces where the patients may have been exposed.


  2. Initial culture -- The samples are transported to the laboratory and plated out, placed on a medium that will support the growth of anthrax, and incubated at the appropriate temperature. This step takes 6-24 hours, depending on the purity of the sample and the concentration of bacteria in it.


  3. Gram stain test -- Bacteria from the culture are placed on a glass microscope slide, stained by the Gram procedure, and then examined under the microscope for their shape and color. If the bacteria are anthrax, they should be rod-shaped and "Gram-positive" (blue). This test takes 10-15 minutes.


  4. Repeat culture -- The bacteria from the initial culture are replated on a medium that will support the growth of anthrax, and incubated at the appropriate temperature. This step takes 24-48 hours.. The aim is to grow up larger quantities of the bacteria for biochemical testing.


  5. Biochemical testing -- In the laboratory, specific chemicals are added to the bacteria to identify them definitivel as anthrax. This step takes 2-3 hours.