Is It Anthrax?
The ability to rapidly detect human cases of anthrax and weed out other causes of disease is paramount not only in getting potentially life-saving antibiotic treatment to those who need it, but also in distributing the expensive therapy only to affected patients. In early November, scientists at the Mayo Clinic announced that they had developed a PCR-based test that can detect the presence of B. anthracis in 35 minutes. The researchers, funded by Roche Diagnostics (Indianapolis, Ind.), were working on the test before September 11, but the project wasn’t a priority at that time. After the attacks, Mayo and Roche accelerated their efforts, and at a November 15 meeting of the U.S. House of Representatives Medical Technology Caucus, Roche officials announced that they had made the test reagents available to 24 laboratories around the country—initially free of charge—and that they intend to seek expedited FDA approval for the test. A nod from the FDA would mean that labs could start using the assays on clinical samples, but until that time the tests will be limited to a “research use only” basis. Currently, the technology has not been validated for the detection of B. anthracis in environmental specimens.

“Level A laboratories—non–public-health laboratories, including clinical laboratories—will not have access to those reagents or assays,” said James Snyder, PhD, Professor of Pathology and Laboratory Medicine and Associate Professor of Microbiology and Immunology, University of Louisville School of Medicine and Director of Microbiology, University of Louisville Hospital, who noted that the technology and supportive equipment for these tests would be cost-prohibitive for most laboratories. The “level A” designation refers to classification within the CDC’s national Laboratory Response Network. Labs are designated level A, B, C, or D, representing increasingly sophisticated bioprotection systems and analytical capabilities.

In the case of either an overt or suspected anthrax attack, level A laboratories would be responsible for presumptive testing of clinical samples to rule out B. anthracis, but Snyder emphasized that the clinical laboratory should not accept or examine environmental or animal specimens. According to CDC recommendations, presumptive identification of anthrax in the hospital laboratory is based on direct Gram’s stain smear of blood, tissue, or cerebrospinal fluid showing gram-positive, rod-shaped bacilli. Suspicious colonies should immediately be sent to the nearest LRN level B laboratory, usually a state health department lab, for confirmatory testing.

In any biowarfare incident, “the challenge is determining that there is in fact a biologic agent responsible for causing a patient’s symptoms, and then identifying that agent,” said Snyder. “Nevertheless, the role of the microbiology lab in this scenario will be no different than it’s everyday mission: to detect, recover, characterize, and identify the etiological agent based on characteristics of culture and microscopic findings.” Snyder suggested that hospital laboratories could best prepare themselves for an attack not by looking to the newest diagnostic technology, but by making sure that their everyday operations are supported by an emergency plan developed in concert with a facility-wide plan, and by taking the lead in educating their own staffs and clinical colleagues.